| 1. |
- Bennet, Louise, et al.
(author)
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Clinical appearance of erythema migrans caused by Borrelia afzelii and Borrelia garinii : effect of the patient´s sex
- 2006
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In: Wiener Klinische Wochenschrift. - : SPRINGER WIEN. - 0043-5325 .- 1613-7671. ; 118:17-18, s. 531-537
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Journal article (peer-reviewed)abstract
- Aim: The aim in this survey was to study the clinical characteristics of infections caused by Borrelia genospecies in patients with erythema migrans where Borrelial origin was confirmed by polymerase chain reaction. The aim was also to study factors influencing the clinical appearance of erythema migrans. Methods: The study was conducted in southern Sweden from May 2001 to December 2003 on patients 18 years and older attending with erythema migrans at outpatient clinics. All erythema migrans were verified by polymerase chain reaction, photographed and categorized into “annular” or “non-annular” lesions. A logistic regression model was used to analyze relations between the appearance of the erythema migrans (i.e., annular or non-annular) and factors that influenced its clinical appearances. Results: A total of 118 patients, 54 women (45.8%) and 64 men (54.2%), fulfilled the inclusion criteria. Of these patients, 74% were infected by B. afzelii, 26% by B. garinii ( p < 0.001). A total of 45% (38/85) of the erythema migrans were annular, 46% (39/85) were non-annular and 9.4% (8/85) were atypical. For men infected by B. afzelii the odds ratio of developing non-annular erythema migrans was 0.09 (95% CI: 0.03 - 0.33) in comparison with women with the same infection. Conclusions: In this prospective study of a large series of erythema migrans, where infecting genospecies were confirmed by polymerase chain reaction, the sex of patients infected with B. afzelii had a strong influence on the appearance of the rash. Patients infected by B. garinii more often had non-annular erythema migrans and a more virulent infection with more individuals presenting with fever, raised levels of C-reactive protein and seroreactivity in the convalescence sera.
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| 2. |
- Bennet, Louise, et al.
(author)
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Clinical Aspects of Erythema Migrans in Southern Sweden
- 2005
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Conference paper (peer-reviewed)abstract
- Background: The aim of this study was to describe and categorize the different predominant patterns of PCR confirmed erythema migrans (EM) and to study possible correlations according to the clinical pictures and Borrelia substrains. Methods: Patients over 18 years old, seeking care with tick exposure and an EM were consecutively included during a study period of three years. We evaluated clinical and laboratory findings with regard to Borrelia burgdorferi s.l. spirochetes detected with nested Osp A PCR in skin biopsy specimens. Laboratory and serology testing were done acute, after 6 weeks and after 6 months. The patients were clinically evaluated at the initial visit and repeatedly after 14 days unitl recovery. Results: 118 patients (women=54, men=64) with a positive B. Burgdorferi s.l. PCR analysis were included. In this area totally 73.7% of the EM were caused by B. afzelii and 26.3% by B. garinii (p=0.0001). Leisons caused by B. garinii had a shorter duration from tick bite to the initial visit (p= 0.001) but there were no differences between the sizes of the EM, indicating a faster development of lesions caused by B. garinii. Patients with lesions caused by B. garinii to a greater extent had presented with fever at the initial visit (p=0.02). Also patients with B. garinii lesions to a greater extent had elevated levels of CRP at the initial visit (p=0.006). 45% of the EM were categorized as “annular”, 27% as “homogeneous”, 19% as “central erythemas” and 9% as “atypical”. The lesions caused by B. afzelii were predominately “annular” and the lesions caused by B. gaarinii were predominately “homogeneous”. Conclusions: In this study most EM were caused by B. afzelii. Leisons caused by B. garinii developed faster and the patients to a greater extent presented with fever and elevated levels of CRP at the initial visit. Leisons caused by B. garinii were mostly homogenous and by B. afzelii were mostly annular.
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| 3. |
- Fraenkel, Carl-Johan, et al.
(author)
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Determination of Novel Borrelia Genospecies in Swedish Ixodes ricinus Ticks.
- 2002
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In: Journal of Clinical Microbiology. - 1098-660X. ; 40:9, s. 3308-3312
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Journal article (peer-reviewed)abstract
- A total of 301 adult questing Ixodes ricinus ticks were collected at 15 different locations along the south and east coasts of Sweden to determine the Borrelia genospecies diversity. Thirty-two ticks (11%) were found to be positive by nested PCR with Borrelia burgdorferi sensu lato-specific primers. Species determination was based on partial sequencing of the 16S rRNA gene and the flagellin gene. Five different Borrelia species were found. The nucleotide sequence of the Borrelia DNA found in two ticks differed extensively from the nucleotide sequences of the Borrelia DNA found in the other ticks, and analysis revealed that they were closely related to the relapsing fever borrelia species Borrelia miyamotoi. This is the first report of a B. miyamotoi-like borrelia in I. ricinus and in Europe. Moreover, the Borrelia DNA of two ticks (6%) clustered within the B. valaisiana complex. B. valaisiana has not previously been reported in Sweden. B. afzelii DNA was found in 14 ticks (44%), and B. garinii DNA was found in 10 ticks (31%). B. burgdorferi sensu stricto DNA was found in four ticks (13%). We conclude that all of the known human-pathogenic species (B. garinii, B. afzelii, and B. burgdorferi sensu stricto) and B. valaisiana found elsewhere in Europe are also present in the Swedish host-seeking tick population and that a B. miyamotoi-like Borrelia species seems to be present in I. ricinus ticks in Europe.
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| 4. |
- Fraenkel, Carl-Johan, et al.
(author)
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In vitro activities of three carbapenems against recent bacterial isolates from severely ill patients at Swedish hospitals
- 2006
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In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 38:10, s. 853-859
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Journal article (peer-reviewed)abstract
- To study the in vitro activity of imipenem, meropenem and ertapenem against common pathogens isolated from patients in intensive care, haematology and dialysis/nephrology units at 7 Swedish university hospitals, a total of 788 isolates were collected during 2002-2003. The distribution of the isolates was as follows: Escherichia coli (n = 140), Klebsiella spp. (n = 132), Proteus spp. (n = 97), Enterobacter spp. (n = 113), Pseudomonas aeruginosa (n = 126), Acinetobacter spp. (n = 53) and Enterococcus faecalis (n = 127). The susceptibility to the 3 carbapenems was determined by E-test, and the MICs were interpreted according to SRGA criteria. All 3 carbapenems were highly active against Enterobacteriaceae. The overall susceptibility to imipenem, meropenem and ertapenem was 90%, 98% and 93%, respectively. Against Enterobacteriaceae, Enterobacter spp. excluded, ertapenem had an equal or lower MIC(90) than meropenem. Apart from being the most active carbapenem against Enterobacteriaceae, meropenem was also the most active carbapenem against P. aeruginosa, whereas imipenem was the most active drug against Acinetobacter spp. The carbapenems are still potent antibiotics. With the introduction of ertapenem, and an expected increase in the carbapenem consumption due to an increased prevalence of strains with extended-spectrum beta-lactamases, continuous surveillance of carbapenem resistance appears to be warranted, with special attention to P. aeruginosa, Enterobacter and Proteus spp.
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| 5. |
- Spreco, Armin, et al.
(author)
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Nowcasting (Short-Term Forecasting) of COVID-19 Hospitalizations Using Syndromic Healthcare Data, Sweden, 2020
- 2022
-
In: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 28:3, s. 564-571
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Journal article (peer-reviewed)abstract
- We report on local nowcasting (short-term forecasting) of coronavirus disease (COVID-19) hospitalizations based on syndromic (symptom) data recorded in regular healthcare routines in Östergötland County (population ≈465,000), Sweden, early in the pandemic, when broad laboratory testing was unavailable. Daily nowcasts were supplied to the local healthcare management based on analyses of the time lag between telenursing calls with the chief complaints (cough by adult or fever by adult) and COVID-19 hospitalization. The complaint cough by adult showed satisfactory performance (Pearson correlation coefficient r>0.80; mean absolute percentage error <20%) in nowcasting the incidence of daily COVID-19 hospitalizations 14 days in advance until the incidence decreased to <1.5/100,000 population, whereas the corresponding performance for fever by adult was unsatisfactory. Our results support local nowcasting of hospitalizations on the basis of symptom data recorded in routine healthcare during the initial stage of a pandemic. © 2022 Centers for Disease Control and Prevention (CDC). All rights reserved.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Alsved, Malin, et al.
(author)
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Droplet, aerosol and SARS-CoV-2 emissions during singing and talking
- 2021
-
Conference paper (peer-reviewed)abstract
- IntroductionAs the pandemic continues to spread, more knowledge is needed about the viral transmission routes. Several super spreading events during the Covid-19 pandemic have been linked to singing in choirs and talking loud. However, in the beginning of the pandemic there was only one study about emitted aerosols and droplets from singing, published in 1968, and only a handful on emissions from talking. Therefore, we conducted a study to measure the aerosol and droplet emissions from talking and singing. We also evaluated the emissions from singing when wearing a face mask.We have further developed our setup so that we collect the aerosol particles from Covid-19 infected patients that are talking and singing, and analyze our samples for SARS-CoV-2, the virus causing Covid-19.MethodTwelve healthy singers (7 professionals, 5 amateurs) were included in the first study part on quantifying the amount of emitted aerosols and droplets. The singers were singing or talking a short consonant rich text repeatedly at a constant pitch with their face in the opening of a funnel. The aerosol particle size and concentration was measured from the other end of the funnel using an aerodynamic particle sizer (APS, 3321, TSI Inc). In addition, the amount of un-evaporated droplets were captured with a high-speed camera and quantified using image analysis.During February and March 2021 we will collect aerosol particles from patients with confirmed Covid-19 that are singing and talking into a funnel. We will use a growth tube condensation collector, a BioSpot (Aerosol Devices), operating at 8 L min-1, and a NIOSH BC-251 cyclone sampler operating at 3.5 L min-1 (TISCH Environmental). The BioSpot collects the whole range of exhaled aerosol particles with high (95%) efficiency into liquid, and the NIOSH cyclone sampler collects particles into three size fractions: <1 µm (filter), 1-4 µm (liquid), >4 µm (liquid). The APS is again used to measure size and concentration of the emitted aerosol particles, so that emissions from infected test subjects can be compared with those of the healthy test subjects. Air samples will be analyzed for detection of SARS-CoV-2 genes, and if possible, SARS-CoV-2 infectivity in cell cultures.ResultsAerosol particle emissions from healthy test subjects were significantly higher during normal singing (median 690, range [320–2870] particles/s) than during normal talking (270 [120–1380] particles/s) (Wilcoxon’s signed rank test, p=0.002). Loud singing produced even more aerosol particles (980 [390–2870] particles/s) than normal singing (p=0.002). The amount of non-evaporated droplets detected by the high-speed camera setup showed similar results: more droplets during loud singing or talking. For both aerosol particle concentrations and droplet numbers, the levels were reduced by on average 70-80% when wearing a surgical face mask.ConclusionsSinging and talking give rise to high aerosol and droplet emissions from the respiratory tract. This is likely an important transmission route for Covid-19. In our upcoming part of the study we hope to determine how much SARS-CoV-2 that is emitted during these social activities.
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| 10. |
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| 11. |
- Alsved, Malin, et al.
(author)
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Exhaled respiratory particles during singing and talking
- 2020
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In: Aerosol Science and Technology. - : Informa UK Limited. - 1521-7388 .- 0278-6826. ; 54:11, s. 245-1248
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Journal article (peer-reviewed)abstract
- Choir singing has been suspended in many countriesduring the Covid-19 pandemic due to incidental reportsof disease transmission. The mode of transmission has been attributed to exhaled droplets, but with the exception of a study on tuberculosis from1968, there is presently almost no scientific evidence ofincreased particle emissions from singing. A substantial number of studies have,however, investigated aerosols emitted from breathing,talking, coughing and sneezing. It has also been shown that justnormal breathing over time can generate more viablevirus aerosol than coughing, since the latter is a less fre-quent activity.Compared to talking, singing often involves continu-ous voicing, higher sound pressure, higher frequencies,deeper breaths, higher peak airflows and more articu-lated consonants. All these factors are likely to increaseexhaled emissions.The aim of this study was to investigate aerosol anddroplet emissions during singing, as compared to talking and breathing. We also examined the presence of SARS-CoV-2 in the air from breathing, talking and singing,and the efficacy of face masks to reduce emissions. In this study we defined aerosol particles as having a drysize in the range 0.5–10mm. Although debatable from anaerosol physics point of view, a cutoff diameter between5 and 10mm is normally used in medicine for classifica-tion of aerosol versus droplet route of transmission. Droplets are here defined as exhaled particles, frommicron size with no upper size limit, and measured dir-ectly at the mouth before complete evaporation, thuspartly in liquid phase.
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| 12. |
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| 13. |
- Alsved, Malin, et al.
(author)
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Infectivity of exhaled SARS-CoV-2 aerosols is sufficient to transmit covid-19 within minutes
- 2023
-
In: Scientific Reports. - 2045-2322. ; 13
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Journal article (peer-reviewed)abstract
- Exhaled SARS-CoV-2-containing aerosols contributed significantly to the rapid and vast spread of covid-19. However, quantitative experimental data on the infectivity of such aerosols is missing. Here, we quantified emission rates of infectious viruses in exhaled aerosol from individuals within their first days after symptom onset from covid-19. Six aerosol samples from three individuals were culturable, of which five were successfully quantified using TCID50. The source strength of the three individuals was highest during singing, when they exhaled 4, 36, or 127 TCID50/s, respectively. Calculations with an indoor air transmission model showed that if an infected individual with this emission rate entered a room, a susceptible person would inhale an infectious dose within 6 to 37 min in a room with normal ventilation. Thus, our data show that exhaled aerosols from a single person can transmit covid-19 to others within minutes at normal indoor conditions.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Alsved, Malin, et al.
(author)
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SARS-CoV-2 in aerosol particles exhaled from COVID-19 infected patients during breathing, talking and singing
- 2021
-
Conference paper (peer-reviewed)abstract
- In the beginning of the COVID-19 pandemic, several super spreader events occurred during singing in choirs, which lead to an increased attention to airborne transmission of SARS-CoV-2, the virus causing COVID-19. Since then, aerosol generation from singing has been studied in more detail, however, only from healthy subjects. In this study, we collected aerosol particles in the exhaled breath of 40 COVID-19 infected patients during breathing, talking and singing, respectively, and analysed the samples for detection of SARS-CoV-2.MethodPatients that were contacted by the COVID-19 testing service due to a positive test result were asked to volunteer for the study. A team of researchers drove a small truck hosting a mobile laboratory to the home address of the patient to perform exhaled breath aerosol collection using a condensational particle collector (BioSpot, Aerosol Devices) and a two-stage cyclone sampler (NIOSH bc-251, Tisch Environmental). Samples were collected for 10 min each when the patient was breathing, talking and singing, respectively.All samples were stored at -80°C until RNA extraction and analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) targeting the N-gene.ResultsA first screening of air samples collected with the BioSpot showed that SARS-CoV-2 could be detected in the exhaled aerosols from three of nine patients during singing or talking. Two of these samples contained 103 and 104 viral RNA copies, corresponding to a viral emission rate of approximately 4 and 25 viruses per second, respectively. Samples from the remaining 31 patients are to be analysed during the spring. We hope to contribute to quantifying and understanding the Covid-19 transmission via the airborne route.This study was approved by the Swedish Ethics Review Authority (2020-07103). This work was supported by AFA Insurances and the Swedish Research Council FORMAS.
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| 18. |
- Alsved, Malin, et al.
(author)
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SARS-CoV-2 in aerosol particles exhaled from COVID-19 infected patients during breathing, talking and singing
- 2021
-
Conference paper (peer-reviewed)abstract
- In the beginning of the COVID-19 pandemic, several super spreader events occurred during choir singing, which lead to an increased attention to airborne transmission of SARS-CoV-2. Since then, aerosol generation from singing has been studied in detail, however, mainly from healthy subjects. In this study, we collected aerosol particles in the exhaled breath of 38 COVID-19 infected patients during breathing, talking and singing, respectively, and analyzed the samples for detection of SARS-CoV-2.MethodPatients that were contacted by the COVID-19 testing service due to a positive test result early in the phase of their infection (median 2, range: 0-6 days from symptom onset) were asked to volunteer for the study. A team of researchers drove a small truck hosting a mobile laboratory to the home address of the patient to perform exhaled breath aerosol collection using a condensational particle collector (BioSpot, Aerosol Devices) and a two-stage cyclone sampler (NIOSH bc-251, Tisch Environmental). Samples were collected for 10 min each when the patients were breathing, talking and singing, respectively. In addition, patient samples from nasopharynx and saliva were collected, and patients filled out a questionnaire about symptoms. All samples were stored at -80 °C until RNA extraction and analysis by reverse transcription quantitative polymerase chain reaction (RT-qPCR) targeting the N-gene.ResultsA first preliminary screening of air samples collected with the BioSpot showed that SARS-CoV-2 could be detected in the exhaled aerosols from 14 of 38 (37%) patients during respiratory activities. 50% of patients in the early phase of the infection, day 0-1 from symptom onset, emitted detectable levels of airborne SARS-CoV-2 RNA, 35% of patients on day 2-3, and 0% of patients on day 4-6. The highest viral RNA concentrations in aerosol samples were found in those collected during singing. Further analysis is ongoing and we hope that our results will contribute to quantifying and understanding the Covid-19 transmission via the airborne route.This study was approved by the Swedish Ethics Review Authority (2020-07103). This work was supported by AFA Insurances and the Swedish Research Council FORMAS.
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| 19. |
- Alsved, Malin, et al.
(author)
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SARS-CoV-2 in exhaled aerosol particles from covid-19 cases and its association to household transmission
- 2022
-
In: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 75:1, s. 50-56
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Journal article (peer-reviewed)abstract
- BACKGROUND: Covid-19 transmission via exhaled aerosol particles has been considered an important route for the spread of infection, especially during super-spreading events involving loud talking or singing. However, no study has previously linked measurements of viral aerosol emissions to transmission rates.METHODS: During Feb-Mar 2021, covid-19 cases that were close to symptom onset were visited with a mobile laboratory for collection of exhaled aerosol particles during breathing, talking and singing, respectively, and of nasopharyngeal and saliva samples. Aerosol samples were collected using a BioSpot-VIVAS and a NIOSH bc-251 two-stage cyclone, and all samples were analyzed by RT-qPCR for SARS-CoV-2 RNA detection. We compared transmission rates between households with aerosol-positive and aerosol-negative index cases.RESULTS: SARS-CoV-2 RNA was detected in at least one aerosol sample from 19 of 38 (50%) included cases. The odds ratio of finding positive aerosol samples decreased with each day from symptom onset (OR 0.55, 95CI 0.30-1.0, p=0.049). The highest number of positive aerosol samples were from singing, 16 (42%), followed by talking, 11 (30%), and the least from breathing, 3 (8%). Index cases were identified for 13 households with 31 exposed contacts. Higher transmission rates were observed in households with aerosol-positive index cases, 10/16 infected (63%), compared to households with aerosol-negative index cases, 4/15 infected (27%) (Chi-square test, p=0.045).CONCLUSIONS: Covid-19 cases were more likely to exhale SARS-CoV-2-containing aerosol particles close to symptom onset and during singing or talking as compared to breathing. This study supports that individuals with SARS-CoV-2 in exhaled aerosols are more likely to transmit covid-19.
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| 20. |
- Alsved, Malin, et al.
(author)
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Size distribution of exhaled aerosol particles containing SARS-CoV-2 RNA
- 2023
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In: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 55:2, s. 158-163
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Journal article (peer-reviewed)abstract
- Background: SARS-CoV-2 in exhaled aerosols is considered an important contributor to the spread of COVID-19. However, characterizing the size distribution of virus-containing aerosol particles has been challenging as high concentrations of SARS-CoV-2 in exhaled air is mainly present close to symptom onset. We present a case study of a person with COVID-19 who was able to participate in extensive measurements of exhaled aerosols already on the day of symptom onset and then for the following three days. Methods: Aerosol collection was performed using an eight-stage impactor while the subject was breathing, talking and singing, for 30 min each, once every day. In addition, nasopharyngeal samples, saliva samples, room air samples and information on symptom manifestations were collected every day. Samples were analyzed by RT-qPCR for detection of SARS-CoV-2 RNA. Results: SARS-CoV-2 RNA was detected in seven of the eight particle size fractions, from 0.34 to >8.1 µm, with the highest concentrations found in 0.94–2.8 µm particles. The concentration of SARS-CoV-2 RNA was highest on the day of symptom onset, and declined for each day thereafter. Conclusion: Our data showed that 90% of the exhaled SARS-CoV-2 RNA was found in aerosol particles <4.5 µm, indicating the importance of small particles for the transmission of COVID-19 close to symptom onset. These results are important for our understanding of airborne transmission, for developing accurate models and for selecting appropriate mitigation strategies.
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| 21. |
- Alsved, Malin, et al.
(author)
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Sources of Airborne Norovirus in Hospital Outbreaks
- 2020
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In: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1537-6591 .- 1058-4838. ; 70:10, s. 2023-2028
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Journal article (peer-reviewed)abstract
- BACKGROUND: Noroviruses are the major cause of viral gastroenteritis. Disease transmission is difficult to prevent and outbreaks in healthcare facilities commonly occur. Contact with infected persons and contaminated environments are believed to be the main routes of transmission. However, noroviruses have recently been found in aerosols and airborne transmission has been suggested. The aim of our study was to investigate associations between symptoms of gastroenteritis and presence of airborne norovirus, and to investigate the size of norovirus carrying particles.METHODS: Air sampling was repeatedly performed close to 26 patients with norovirus infections. Samples were analysed for norovirus RNA by RT-qPCR. The times since the patients' last episodes of vomiting and diarrhoea were recorded. Size separating aerosol particle collection was also performed in ward corridors.RESULTS: Norovirus RNA was found in 21 (24%) of 86 air samples from 10 different patients. Only air samples during outbreaks, or before a succeeding outbreak, tested positive for norovirus RNA. Airborne norovirus RNA was also strongly associated with a shorter time period since the last vomiting episode (odds ratio 8.1, p=0.04 within 3 hours since the last vomiting episode). The concentration of airborne norovirus ranged from 5-215 copies/m3, and detectable amounts of norovirus RNA were found in particles <0.95 µm and >4.51 µm.CONCLUSIONS: The results suggest that recent vomiting is the major source of airborne norovirus and imply a connection between airborne norovirus and outbreaks. The presence of norovirus RNA in submicrometre particles indicates that airborne transmission can be an important transmission route.
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| 22. |
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| 23. |
- Fraenkel, Carl Johan, et al.
(author)
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Incidence of Hospital Norovirus Outbreaks and Infections Using 2 Surveillance Methods in Sweden
- 2017
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In: Infection Control & Hospital Epidemiology. - : Cambridge University Press (CUP). - 0899-823X .- 1559-6834. ; 38:1, s. 96-102
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Journal article (peer-reviewed)abstract
- OBJECTIVE To evaluate 2 different methods of surveillance and to estimate the incidence of norovirus (NoV) outbreaks in hospitals. DESIGN Prospective observational study. SETTING All 194 hospital wards in southern Sweden during 2 winter seasons (2010-2012). METHODS Clinical surveillance based on outbreak reports of 2 or more clinical cases, with symptom onset within 5 days, was compared with laboratory surveillance based on positive NoV results among inpatients. At least 2 NoV positive patients sampled within 5 days at a ward defined a cluster. Outbreak reports including at least 1 NoV positive case and clusters including at least 1 NoV positive patient with 5 or more days from ward admission to sampling were defined as NoV outbreaks. RESULTS During the study periods 135 NoV outbreaks were identified; 74 were identified by both clinical and laboratory surveillance, 18 were identified only by outbreak reports, and 43 were identified only by laboratory surveillance. The outbreak incidence was 1.0 (95% CI, 0.8-1.2) and 0.5 (95% CI, 0.3-0.6) per 1,000 admissions for the 2 different seasons, respectively. To correctly identify NoV outbreaks, the sensitivity and positive predictive value of the clinical surveillance were 68% and 88% and of the laboratory surveillance were 86% and 81%, respectively. CONCLUSION The addition of laboratory surveillance significantly improves outbreak surveillance and provides a more complete estimate of NoV outbreaks in hospitals. Laboratory surveillance can be recommended for evaluation of clinical surveillance.
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| 24. |
- Fraenkel, Carl-Johan
(author)
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On norovirus outbreaks and transmission in hospitals
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Abstract Noroviruses are now the leading cause of gastroenteritis worldwide. Noroviruses are effectively transmitted due to a low infectious dose, viral shedding in high concentrations, environmental stability, and they induce only a limited immunity after infection. Especially, the norovirus variants of genotype II.4 (GII.4) have seemed greatly adapted for pandemic spread. The high infectivity of noroviruses result in frequent outbreaks, particularly at healthcare facilities. Hospital norovirus outbreaks cause excess morbidity among vulnerable inpatients, ill staff, shortage of beds and economic loss. In the first study, using two outbreak surveillance methods, based on either clinical reporting or clustering of positive laboratory results, incidence of norovirus outbreaks at all hospital wards in Skåne was estimated to 0.5 to 0.2 per ward and winter season, 2010-2012. In total, 135 outbreaks were detected, 74 with both methods, 18 only by clinical reporting and 43 only with laboratory surveillance. Laboratory surveillance performed better at identifying outbreaks and seem a stable option for continuous surveillance, but the combination of both surveillance methods would be preferred. In the second study, the first patient in each outbreak (n 65), was compared with patients not involved in any outbreak (n 186), to analyse factors associated with outbreak development. Sharing room with other patients, old age, comorbidities, onset of disease at the ward and vomiting were independently associated with an outbreak outcome. Infection with norovirus GII.4 was associated with outbreak development and vomiting, suggesting a possible explanation for the efficient transmission of GII.4 in hospitals.In a third study, aspects of possible airborne transmission was investigated, by analysis of air samples collected in the proximity of 26 norovirus patients. Norovirus genome in the air was a common finding during outbreaks, supporting the hypothesis that airborne transmission might be of importance. The size of the norovirus carrying particles and the concentration of norovirus genomes in air allow for the possibility of airborne transmission. A short time period since the last vomiting event in the room was associated with norovirus positive air samples, indicating vomiting as the major source of airborne norovirus.In the final study, aspects of environmental transmission was explored. Different exposures related to room admission and association to norovirus acquisition at the ward were analysed. A room stay at a room with a prior occupant with norovirus infection was a small but independent risk factor for acquisition of norovirus infection. Norovirus acquisition was not observed in association to sharing room with patients with recently resolved symptoms of norovirus infection.In conclusion, prevention of hospital outbreaks may be improved by better recognition of factor associated with outbreak development and improved surveillance. Airborne transmission and dissemination of norovirus, originating from vomiting events, may be an important mode of transmission, but further studies are needed. Environmental transmission from prior room occupants stress cleaning and disinfection as important preventive measures.
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| 25. |
- Fraenkel, Carl-Johan, et al.
(author)
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The First Swedish Outbreak with VIM-2-Producing Pseudomonas aeruginosa, Occurring between 2006 and 2007, Was Probably Due to Contaminated Hospital Sinks
- 2023
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In: Microorganisms. - : MDPI. - 2076-2607. ; 11:4
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Journal article (peer-reviewed)abstract
- Multidrug-resistant Pseudomonas aeruginosa is an increasing clinical problem worldwide. The aim of this study was to describe the first outbreak of a Verona integron-borne metallo-ss-lactamase (VIM)-2-producing P. aeruginosa strain in Sweden and its expansion in the region. A cluster of multidrug-resistant P. aeruginosa appeared at two neighbouring hospitals in 2006. The isolates were characterized by PCR, pulsed-field gel electrophoresis (PFGE), and whole-genome sequencing. Patient charts, laboratory records, and hygiene routines were reviewed, and patients, staff, and the environment were screened. The investigation revealed a clonal outbreak of a VIM-2-producing P. aeruginosa strain belonging to the high-risk clonal complex 111, susceptible only to gentamicin and colistin. No direct contact between patients could be established, but most of them had stayed in certain rooms/wards weeks to months apart. Cultures from two sinks yielded growth of the same strain. The outbreak ended when control measures against the sinks were taken, but new cases occurred in a tertiary care hospital in the region. In conclusion, when facing prolonged outbreaks with this bacterium, sinks and other water sources in the hospital environment should be considered. By implementing proactive control measures to limit the bacterial load in sinks, the waterborne transmission of P. aeruginosa may be reduced.
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| 26. |
- Hirdman, Gabriel, et al.
(author)
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Proteomic characteristics and diagnostic potential of exhaled breath particles in patients with COVID-19
- 2023
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In: Clinical Proteomics. - : Springer Science and Business Media LLC. - 1542-6416 .- 1559-0275. ; 20:1
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Journal article (peer-reviewed)abstract
- BACKGROUND: SARS-CoV-2 has been shown to predominantly infect the airways and the respiratory tract and too often have an unpredictable and different pathologic pattern compared to other respiratory diseases. Current clinical diagnostical tools in pulmonary medicine expose patients to harmful radiation, are too unspecific or even invasive. Proteomic analysis of exhaled breath particles (EBPs) in contrast, are non-invasive, sample directly from the pathological source and presents as a novel explorative and diagnostical tool.METHODS: Patients with PCR-verified COVID-19 infection (COV-POS, n = 20), and patients with respiratory symptoms but with > 2 negative polymerase chain reaction (PCR) tests (COV-NEG, n = 16) and healthy controls (HCO, n = 12) were prospectively recruited. EBPs were collected using a "particles in exhaled air" (PExA 2.0) device. Particle per exhaled volume (PEV) and size distribution profiles were compared. Proteins were analyzed using liquid chromatography-mass spectrometry. A random forest machine learning classification model was then trained and validated on EBP data achieving an accuracy of 0.92.RESULTS: Significant increases in PEV and changes in size distribution profiles of EBPs was seen in COV-POS and COV-NEG compared to healthy controls. We achieved a deep proteome profiling of EBP across the three groups with proteins involved in immune activation, acute phase response, cell adhesion, blood coagulation, and known components of the respiratory tract lining fluid, among others. We demonstrated promising results for the use of an integrated EBP biomarker panel together with particle concentration for diagnosis of COVID-19 as well as a robust method for protein identification in EBPs.CONCLUSION: Our results demonstrate the promising potential for the use of EBP fingerprints in biomarker discovery and for diagnosing pulmonary diseases, rapidly and non-invasively with minimal patient discomfort.
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| 27. |
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| 28. |
- Löndahl, Jakob, et al.
(author)
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Luftvägsvirus vid arbetsplatser - Smittvägar, riskfaktorer och skyddsåtgärder
- 2021
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In: Arbete och hälsa. - 0346-7821. ; 55:2, s. 1-53
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Journal article (peer-reviewed)abstract
- Att spridning av sjukdomsframkallande luftvägsvirus kostar samhället enorma resurser har blivit uppenbart för alla under covid-19, men ovälkomna virus har varit människans följeslagare genom hela historien och ständigt uppkommer nya varianter med särskilt hög smittsamhet eller dödlighet. Riskerna har ökat med befolkningstillväxt och globalisering. Samtidigt har våra förutsättningar att skydda oss också har blivit bättre genom ökad kunskap och framsteg inom medicin och teknik.Syftet med denna kunskapssammanställning är att beskriva smittvägar, riskfaktorer och skyddsåtgärder för infektiös luftvägssjukdom och därmed bidra till en minskad smittrisk vid arbetsplatser. Mycket av innehållet bygger på forskning om influensa och covid-19, men även en rad andra luftvägsinfektioner är inkluderade.Spridning av virus har här delats upp i tre smittvägar: inandning, direkt deponering och kontakt. Risken för smitta via inandning av virus är särskilt stor när avstånden mellan människor är korta och uppehållstiden lång i lokaler med dålig ventilation. Risken ökar om det också pågår aktiviteter som innebär spridning av virusinnehållande aerosolpartiklar till luften, såsom högt tal eller sång eller vissa medicinska procedurer, eller om den inandade luftmängden är förhöjd, som vid tungt arbete. Virusöverföring via direkt deponering sker när stora smittbärande droppar stänker direkt på en mottagare vid exempelvis hosta. Virusspridning via både inandning och direkt deponering sker på olika sätt genom luften, men benämns här inte ”luftsmitta” eftersom detta begrepp åtminstone enligt klassisk medicinsk indelning syftat på (effektiv) smitta via inandning över avstånd mer än enstaka meter och eftersom det främst använts för sjukdomar som är mycket allvarliga och därför kräver extrema skyddsåtgärder. Smitta via kontakt kan ske antingen via direkt beröring eller genom mellanled, som handtag eller andra ytor.Samtliga tre smittvägar är välbelagda för luftvägsvirus i den vetenskapliga litteraturen, men deras relativa betydelse varierar beroende situation, virustyp och interventioner för att minska smitta. För covid-19 pekar mycket forskning mot att inandning är en dominerande smittväg i många miljöer. Vissa yrkesgrupper, särskilt inom vårdsektorn, löper en förhöjd risk att smittas av luftvägsvirus.En lång rad skyddsåtgärder finns tillgängliga för att på olika sätt minska smittrisker: distans, hygien, fysiska barriärer, ventilation, administrativa åtgärder (exempelvis information, regleringar, kontroller, checklistor) och personlig skyddsutrustning. De flesta av dessa åtgärder har starkt stöd av vetenskapliga studier.
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| 29. |
- Nygren, David, et al.
(author)
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Association between SARS-CoV-2 and exposure risks in health care workers and university employees – a cross-sectional study
- 2021
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In: Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 2374-4235 .- 2374-4243. ; 53:6, s. 460-468
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Journal article (peer-reviewed)abstract
- BackgroundIn health care workers SARS-CoV-2 has been shown to be an occupational health risk, often associated with transmission between health care workers. Yet, insufficient information on transmission dynamics has been presented to elucidate the precise risk factors for contracting SARS-CoV-2 in this group.MethodsIn this cross-sectional study, we investigated association between questionnaire answers on potential exposure situations and SARS-CoV-2-positivity. Health care workers with and without COVID-19-patient contact at nine units at Skåne University Hospitals in Malmö and Lund, Sweden and university employees from Lund University, Sweden were enrolled. To limit impact of health care worker to health care worker transmission, units with known outbreaks were excluded. A SARS-CoV-2-positive case was defined by a previous positive PCR or anti-SARS-CoV-2 IgG in the ZetaGene COVID-19 Antibody Test.ResultsSARS-CoV-2-positivity was detected in 11/51 (22%) health care workers in COVID-19-units, 10/220 (5%) in non-COVID-19-units and 11/192 (6%) University employees (p = .001, Fischer’s exact). In health care workers, SARS-CoV-2-positivity was associated with work in a designated COVID-19-unit (OR 5.7 (95CI 2.1–16)) and caring for COVID-19-patients during the majority of shifts (OR 5.4 (95CI 2.0–15)). In all participants, SARS-CoV-2-positivity was associated with a confirmed COVID-19 case (OR 10 (95CI 2.0–45)) in the household.ConclusionOur study confirmed previous findings of elevated risk of acquiring SARS-CoV-2 in health care workers in COVID-19-units, despite exclusion of units with known outbreaks. Interestingly, health care workers in non-COVID-19-units had similar risk as University employees. Further measures to improve the safety of health care workers might be needed.
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| 30. |
- Starlander, Gustaf, et al.
(author)
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The first Swedish outbreak with VIM-2-producing Pseudomonas aeruginosa was prolonged and probably due to contaminated hospital sinks
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Other publication (other academic/artistic)abstract
- Background: Metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa is an increasing clinical problem worldwide. VIM-2 is the predominant enzyme, and it has been linked to several outbreaks. During the spring of 2006, a cluster of patients were colonized or infected with multiresistant Pseudomonas aeruginosa at two neighbouring hospitals in southeast Sweden.Aim: To describe the first documented outbreak of a VIM-2-producing P. aeruginosa strain in Sweden.Methods: The isolates were characterized with PCR, pulse-field gel electrophoresis (PFGE), and whole genome sequencing. Patient charts, laboratory records and hygiene routines were reviewed, and patients, staff and the environment were screened.Findings: The investigation revealed that it was a clonal outbreak of a VIM-2-producing P. aeruginosa strain susceptible only to gentamicin and colistin. It belonged to the high-risk clonal complex 111. No direct contact between patients could be established, but most of them had stayed in the same room/wards with weeks to months apart. Environmental cultures from two sinks yielded growth of P. aeruginosa with the same PFGE-pattern as the patient isolates. The outbreak ended when control measures against the sinks were taken.Conclusions: Contaminated hospital sinks were the probable reservoir in the first nosocomial outbreak of MBL-producing P. aeruginosa in Sweden. When facing prolonged outbreaks with this bacterium, sinks and other water sources in the hospital environment should be considered. By implementing proactive control measures to limit the bacterial load in sinks and plumbing systems, the waterborne transmission of P. aeruginosa could probably be reduced.
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| 31. |
- Strand, Rasmus, et al.
(author)
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Post-outbreak serological screening for SARS-CoV-2 infection in healthcare workers at a Swedish University Hospital
- 2021
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In: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 53:9, s. 707-712
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Journal article (peer-reviewed)abstract
- BACKGROUND: Nosocomial outbreaks of coronavirus disease 2019 (COVID-19) can have devastating consequences from both a resource cost and patient healthcare perspective. Relying on reverse transcription-polymerase chain reaction (RT-PCR) for identifying infected individuals may result in missed cases. Screening for antibodies after an outbreak can help to find missed cases and better illuminate routes of transmission.METHODS: In this study, we present the results of a serological screening of the healthcare workers (HCWs) on a ward for infectious diseases in Sweden with a point-of-care antibody test 8 weeks after an outbreak of COVID-19. In all, 107/123 (87%) of HCWs who were tested with RT-PCR in the outbreak investigation participated in this study on seroprevalence. Participants were also asked to fill out a questionnaire entailing epidemiological data. The cohort was stratified by RT-PCR result and the resulting groups were compared to each other.RESULTS: Six (8%) HCWs who were tested RT-PCR negative during the outbreak investigation had developed specific IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These HCWs had all worked shifts with colleagues who later were tested RT-PCR positive during the outbreak.CONCLUSIONS: Our results indicate that a serological follow-up screening after an outbreak may be used as a complement to virus detection in an outbreak situation. However, immunoglobulin (Ig) G-detection should also be performed at the start of an outbreak, to facilitate interpretation of the results.
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| 32. |
- Thorarinsdottir, Hulda, et al.
(author)
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Catheter-related infections : A Scandinavian observational study on the impact of a simple hygiene insertion bundle
- 2020
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In: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 64:2, s. 224-231
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Journal article (peer-reviewed)abstract
- BACKGROUND: Catheter-related infections (CRIs) and catheter-related bloodstream infections (CRBSIs) are among the most frequent hospital acquired infections. CRI/CRBSI studies in Scandinavian cohorts are scarce. The primary aim of this study was to investigate the CRI/CRBSI incidence and the association between potential risk factors, including the introduction of a simple hygiene insertion bundle and CRIs at a large university hospital in Sweden.METHODS: We retrospectively included all patients aged 12 and above who received a central venous catheter (CVC) or a central dialysis catheter during a two-year period, one year before and one year after the implementation of a simple hygiene insertion bundle. Microbiological data, including catheter tip cultures and blood cultures, were merged with CVC insertion data.RESULTS: A total of 1,722 catheter insertions in 1,428 patients were included. CRI and CRBSI incidence were 1.86/1,000 and 0.62/1,000 catheter days, respectively. In a multivariable regression model, the implementation of a simple hygiene insertion bundle was the independent factor most strongly associated with significantly lower CRI-incidence (95% Confidence Interval (CI) of Odds Ratio (OR) 0.23 - 0.92, p = 0.029). Choosing multiple lumen catheters was associated with increasing CRI-incidence (95% CI of OR 1.11-2.39, p = 0.013).CONCLUSION: The incidence of catheter-related infections and catheter-related bloodstream infections in this Scandinavian cohort was low. The implementation of a simple hygiene insertion bundle seems to be an effective intervention for reducing catheter-related infections. The use of multiple-lumen catheters is associated with increased risk of catheter-related infections.
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| 33. |
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| 34. |
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| 35. |
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| 36. |
- Thuresson, Sara, et al.
(author)
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Airborne SARS-CoV-2 during childbirth
- 2023
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Conference paper (peer-reviewed)abstract
- Airborne SARS CoV 2 is considered to play a major role in covid 19 transmission, and has been found in several hospital environments. There is a need to investigate the presence of airborne SARS CoV 2 in other hospital areas than traditional infectious disease wards. The results from the present study can contribute to a better understanding of the risk of covid 19 transmission by aerosols at delivery wards.
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| 37. |
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| 38. |
- Thuresson, Sara, et al.
(author)
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Airborne SARS-CoV-2 RNA collected during childbirth and autopsy
- 2023
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Conference paper (peer-reviewed)abstract
- Airborne SARS-CoV-2 is considered to play a major role in covid-19 transmission, and several studies have reported its presence in hospital environments, including corridors, patient rooms, cohort rooms and ICUs (Dinoi et al., 2022). The risk of airborne virus have been associated with a number of factors, such as low ventilation, high patient viral load and in some cases, certain medical procedures.However, specific medical situations still deserve further investigation. One such situation of interest is childbirth, as respiratory emissions, which could contain virus, are increased due to heavy breathing during labor. Another situation with potential risk for airborne SARS-CoV-2 is autopsy.The aim of the current study was to further explore the presence of airborne SARS-CoV-2 RNA during childbirth and autopsy.The results in this study can increase our understanding about the risk of covid-19 transmission by aerosols at delivery wards and during autopsy, even though the sample material is small. Reports of airborne SARS-CoV-2 in hospital environments contribute to improving guidelines for protective equipment for healthcare personnel working with such patients.
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| 39. |
- Thuresson, Sara, et al.
(author)
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Airborne Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Hospitals : Effects of Aerosol-Generating Procedures, HEPA-Filtration Units, Patient Viral Load, and Physical Distance
- 2022
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In: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 75:1, s. 89-96
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Journal article (peer-reviewed)abstract
- BACKGROUND: Transmission of coronavirus disease 2019 (COVID-19) can occur through inhalation of fine droplets or aerosols containing infectious virus. The objective of this study was to identify situations, patient characteristics, environmental parameters, and aerosol-generating procedures (AGPs) associated with airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus.METHODS: Air samples were collected near hospitalized COVID-19 patients and analyzed by RT-qPCR. Results were related to distance to the patient, most recent patient diagnostic PCR cycle threshold (Ct) value, room ventilation, and ongoing potential AGPs.RESULTS: In total, 310 air samples were collected; of these, 26 (8%) were positive for SARS-CoV-2. Of the 231 samples from patient rooms, 22 (10%) were positive for SARS-CoV-2. Positive air samples were associated with a low patient Ct value (OR, 5.0 for Ct <25 vs >25; P = .01; 95% CI: 1.18-29.5) and a shorter physical distance to the patient (OR, 2.0 for every meter closer to the patient; P = .05; 95% CI: 1.0-3.8). A mobile HEPA-filtration unit in the room decreased the proportion of positive samples (OR, .3; P = .02; 95% CI: .12-.98). No association was observed between SARS-CoV-2-positive air samples and mechanical ventilation, high-flow nasal cannula, nebulizer treatment, or noninvasive ventilation. An association was found with positive expiratory pressure training (P < .01) and a trend towards an association for airway manipulation, including bronchoscopies and in- and extubations.CONCLUSIONS: Our results show that major risk factors for airborne SARS-CoV-2 include short physical distance, high patient viral load, and poor room ventilation. AGPs, as traditionally defined, seem to be of secondary importance.
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| 40. |
- Thuresson, Sara, et al.
(author)
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Characteristics of SARS-CoV-2-containing aerosols in hospital corridors
- 2022
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In: ; , s. 1-1
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Conference paper (peer-reviewed)abstract
- The aim of this work is to investigate the presence of airborne SARS-CoV-2 in corridors of infection wards, and gain more detailed size information of SARS-CoV-2-containing aerosols. Associations between SARS-CoV-2 presence and relative humidity and/or temperature in the facilities is also explored.
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| 41. |
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Thuresson, Sara, et al.
(author)
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One year weekly size-resolved air sampling of SARS-CoV-2 in hospital corridors and relations to the indoor environment
- 2024
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In: Indoor Air. - 0905-6947. ; 2024
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Journal article (peer-reviewed)abstract
- Background. Airborne SARS-CoV-2 plays a prominent role in COVID-19 transmission. Numerous studies have sampled air from patient rooms, but airborne spread to other hospital areas such as corridors is less investigated. Methods. Size-fractionated aerosol particles were collected weekly, with 12 hours of sampling time daily, in corridors at two infectious disease wards in southern Sweden between March 2020 and May 2021. Samples were analysed with real-time reverse transcription polymerase chain reaction (RT-qPCR) for detection of SARS-CoV-2 RNA. Indoor temperature, relative humidity, and CO2 concentration were monitored during the sampling period. Results. 20 of the 784 collected samples contained SARS-CoV-2 RNA, although in low concentrations. Positive air samples were found in sizes between 0.14 and 8.1 μm, but none >8.1 μm. 45% were found in submicron particles. No clear seasonal pattern was observed among the positive samples. There was no significant difference in the positivity rate of the samples between the two wards. Conclusions. SARS-CoV-2 was only detected in 2.6% of the aerosol samples, which indicates that the spread of airborne virus from patient rooms to the corridor was limited.
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| 46. |
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| 47. |
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| 48. |
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| 49. |
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| 50. |
- Zhang, Madeline X., et al.
(author)
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Generation of aerosols by noninvasive respiratory support modalities : a systematic review and meta-analysis
- 2023
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In: JAMA Network Open. - 2574-3805. ; 6:10
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Journal article (peer-reviewed)abstract
- Importance: Infection control guidelines have historically classified high-flow nasal oxygen and noninvasive ventilation as aerosol-generating procedures that require specialized infection prevention and control measures. Objective: To evaluate the current evidence that high-flow nasal oxygen and noninvasive ventilation are associated with pathogen-laden aerosols and aerosol generation. Data Sources: A systematic search of EMBASE and PubMed/MEDLINE up to March 15, 2023, and CINAHL and ClinicalTrials.gov up to August 1, 2023, was performed. Study Selection: Observational and (quasi-)experimental studies of patients or healthy volunteers supported with high-flow nasal oxygen or noninvasive ventilation were selected. Data Extraction and Synthesis: Three reviewers were involved in independent study screening, assessment of risk of bias, and data extraction. Data from observational studies were pooled using a random-effects model at both sample and patient levels. Sensitivity analyses were performed to assess the influence of model choice. Main Outcomes and Measures: The main outcomes were the detection of pathogens in air samples and the quantity of aerosol particles. Results: Twenty-four studies were included, of which 12 involved measurements in patients and 15 in healthy volunteers. Five observational studies on SARS-CoV-2 detection in a total of 212 air samples during high-flow nasal oxygen in 152 patients with COVID-19 were pooled for meta-analysis. There was no association between high-flow nasal oxygen and pathogen-laden aerosols (odds ratios for positive samples, 0.73 [95% CI, 0.15-3.55] at the sample level and 0.80 [95% CI, 0.14-4.59] at the patient level). Two studies assessed SARS-CoV-2 detection during noninvasive ventilation (84 air samples from 72 patients). There was no association between noninvasive ventilation and pathogen-laden aerosols (odds ratios for positive samples, 0.38 [95% CI, 0.03-4.63] at the sample level and 0.43 [95% CI, 0.01-27.12] at the patient level). None of the studies in healthy volunteers reported clinically relevant increases in aerosol particle production by high-flow nasal oxygen or noninvasive ventilation. Conclusions and Relevance: This systematic review and meta-analysis found no association between high-flow nasal oxygen or noninvasive ventilation and increased airborne pathogen detection or aerosol generation. These findings argue against classifying high-flow nasal oxygen or noninvasive ventilation as aerosol-generating procedures or differentiating infection prevention and control practices for patients receiving these modalities..
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