| 1. |
- Erra, Elina O, et al.
(författare)
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A single dose of vero cell-derived Japanese encephalitis (JE) vaccine (Ixiaro) effectively boosts immunity in travelers primed with mouse brain-derived JE vaccines
- 2012
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 55:6, s. 825-834
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:A significant part of the world population lives in areas with endemic Japanese encephalitis (JE). For travelers from nonendemic countries, Vero cell-derived vaccine (JE-VC; Ixiaro) has replaced traditional mouse brain-derived vaccines (JE-MB) associated with safety concerns. The 2 vaccines are derived from different viral strains: JE-VC from the SA14-14-2 strain and JE-MB from the Nakayama strain. No data exist regarding whether JE-VC can be used to boost immunity after a primary series of JE-MB; therefore, a primary series of JE-VC has been recommended to all travelers regardless of previous vaccination history.METHODS:One hundred twenty travelers were divided into 4 groups: Volunteers with no prior JE vaccination received primary immunization with (group 1) JE-MB or (group 2) JE-VC, and those primed with JE-MB received a single booster dose of (group 3) JE-MB or (group 4) JE-VC. Immune responses were tested before and 4-8 weeks after vaccination using plaque reduction neutralization test (PRNT) against both vaccine strains.RESULTS:In vaccine-naive travelers, the vaccination response rate for test strains Nakayama and SA14-14-2 was 100% and 87% after primary vaccination with JE-MB and 87% and 94% after JE-VC, respectively. Antibody levels depended on the target virus, with higher titers against homologous than heterologous PRNT(50) target strain (P < .001). In travelers primed with JE-MB, vaccination response rates were 91% and 91%, and 98% and 95% after a booster dose of JE-MB or JE-VC, respectively. Subgroup analysis revealed that a higher proportion of primed (98%/95%) than nonprimed (39%/42%) volunteers responded to a single dose of JE-VC (P < .001).CONCLUSIONS:A single dose of JE-VC effectively boosted immunity in JE-MB-primed travelers. Current recommendations should be reevaluated.CLINICAL TRIALS REGISTRATION:NCT01386827.
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| 2. |
- Erra, Elina O., et al.
(författare)
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Cross-protection elicited by primary and booster vaccinations against Japanese encephalitis : A two-year follow-up study
- 2013
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Ingår i: Vaccine. - : Elsevier BV. - 0264-410X .- 1873-2518. ; 32:1, s. 119-123
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Tidskriftsartikel (refereegranskat)abstract
- Background: The inactivated Vero cell-derived vaccine (JE-VC, IXIARO) has replaced the traditional mouse brain-derived preparations (JE-MB) in travelers' vaccinations against Japanese encephalitis. We showed recently that a single JE-VC dose efficiently boosts immunity in JE-MB-primed vaccinees, and that JE-VC elicits cross-protective immunity against non-vaccine genotypes, including the emerging genotype I. While these studies only provided short-term data, the present investigation evaluates the longevity of seroprotection in the same volunteers.Methods:The study comprised 48 travelers who had received (1) JE-VC primary series, (2) JE-MB primary series followed by a single JE-VC booster dose, or (3) JE-MB primary series and a single JE-MB booster dose. Serum samples were collected two years after the last vaccine dose, and evaluated with the plaque-reduction neutralization test against seven Japanese encephalitis virus strains representing genotypes I-IV. PRNT50 titers >= 10 were considered protective.Results:Two years after the primary series with JE-VC, 87-93% of the vaccinees proved to be cross-protected against test strains representing genotypes II-IV and 73% against those of genotype I. After a single homologous or heterologous booster dose to JE-MB-primed subjects, the two-year seroprotection rates against genotype I-IV strains were 89-100%.Conclusions:After JE-VC primary series, seroprotection appeared to wane first against genotype I. The first booster should not be delayed beyond two years. In JE-MB-primed subjects, a single JE-VC booster provided cross-protective immunity against genotype I-IV strains in almost all vaccinees, suggesting an interval of two years or even longer for the second booster. These data further support the use of a single JE-VC dose for boosting JE-MB immunity.
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| 3. |
- Erra, Elina O, et al.
(författare)
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Cross-protective capacity of Japanese encephalitis (JE) vaccines against circulating heterologous JE virus genotypes
- 2013
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 56:2, s. 267-270
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Tidskriftsartikel (refereegranskat)abstract
- Current Japanese encephalitis vaccines are derived from strains of genotype III, yet heterologous genotypes are emerging in endemic areas. Inactivated vaccines given to European travelers were found to elicit protective levels of neutralizing antibodies against heterologous strains of genotypes I-IV.
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| 4. |
- Kantele, Anu, et al.
(författare)
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Three-dose versus four-dose primary schedules for tick-borne encephalitis (TBE) vaccine FSME-immun for those aged 50 years or older : A single-centre, open-label, randomized controlled trial
- 2022
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Ingår i: Vaccine. - : Elsevier. - 0264-410X .- 1873-2518. ; 40:9, s. 1299-1305
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Tidskriftsartikel (refereegranskat)abstract
- Background: TBE vaccination failures among those past middle age have raised concern about immune response declining with age. We investigated immunogenicity of the TBE-vaccine FSME-Immun among those aged 50+ years using the standard three-dose primary series and alternative four-dose schedules. Methods: In this single-centre, open-label, randomized controlled trial, 200 TBE-naive Swedish adults were given primary TBE vaccination with FSME-Immun. Those aged 50+ years (n = 150) were randomized to receive the standard three-dose (days 0-30-360) or one of two four-dose series (0-7-21-360; 0-30- 90-360). For participants < 50 years (n = 50) the standard three-dose schedule was used. Titres of neu-tralizing antibodies were determined on days 0, 60, 120, 360, and 400. The main outcome was the log titre of TBE virus-specific neutralizing antibodies on day 400. Results: The three-dose schedule yielded lower antibody titres among those aged 50+ years than the younger participants on day 400 (geometric mean titre 41 versus 74, p < 0.05). The older group showed higher titres for the four-dose 0-7-21-360 than the standard three-dose schedule both on day 400 (103 versus 41, p < 0.01; primary end point) and at the other testing points (days 60,120, 360). Using the other four-dose schedule (0-30-90-360), no such difference was observed on day 400 (63 versus 41, NS). Conclusion: Immune response to the TBE vaccine declined with age. A four-dose schedule (0-7-21-360) may benefit those aged 50 years or older. This study is registered at ClinicalTrials.gov, NCT01361776. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
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| 5. |
- Stefansson, Måns, et al.
(författare)
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Safety and tolerability of frozen, capsulized autologous faecal microbiota transplantation. A randomized double blinded phase I clinical trial
- 2023
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- Background: Faecal microbiota transplantation (FMT) is recommended treatment for recurrent Clostridioides difficile infection and is studied as a potential modifier of other gastrointestinal and systemic disorders. Autologous FMT limits the potential risks of donor transplant material and enables prophylactic treatment. Capsulized FMT is convenient and accessible, but safety data are lacking.Aims: To describe safety and tolerability of capsules containing autologous FMT, compared to placebo, in healthy volunteers treated with antibiotics.Method: Healthy volunteers without antibiotic exposure during the past three months, that had a negative Clostridioides difficile stool sample, were recruited. Study persons donated faeces for production of capsules containing autologous microbiota. They were then given Clindamycin for seven days to disrupt the intestinal microbiota, which was followed by a two-day washout. Study persons were then randomized (1:1) to unsupervised treatment with autologous faecal matter or placebo, with two capsules twice daily for five days. A standardized questionnaire about side effects and tolerability, daily until day 28, and on days 60 and 180, was completed.Results: Twenty-four study persons were included, all completed the treatment. One person from the placebo and FMT groups each, were lost to follow up from days 21 and 60, respectively. No study person experienced serious side effects, but severe fatigue was reported during the antibiotic period (n = 2). Reported side effects were mild to moderate and there were no significant differences between the groups. Reported general and intestinal health improved significantly and similarly in both groups after the antibiotic treatment. Time to normalized intestinal habits were 17 and 19 days from study start in the placebo group and the FMT group, respectively (p = 0.8).Conclusion: Capsulized frozen autologous faecal microbiota transplantation was safe and well tolerated but did not affect time to normalized intestinal habits compared to placebo.
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| 6. |
- Varnaite, Renata, et al.
(författare)
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Magnitude and Functional Profile of the Human CD4(+) T Cell Response throughout Primary Immunization with Tick-Borne Encephalitis Virus Vaccine
- 2020
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Ingår i: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 204:4, s. 914-922
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Tidskriftsartikel (refereegranskat)abstract
- Tick-borne encephalitis (TBE) is a viral infection of the CNS caused by TBE virus. With no specific treatment available, the only protection is a formalin-inactivated whole virus vaccine. Primary immunization with European TBE vaccines, as recommended by the manufacturers, consists of three vaccine doses administered within a 1-y period. Protection from vaccination is believed to be mediated by Abs, yet T cells may also have a protective role. We set out to characterize the human CD4(+) T cell response throughout primary TBE immunization. The responses were evaluated before vaccination and 1 mo after each vaccine dose. A heterogeneous magnitude of CD4(+) T cell-mediated memory responses was observed in regard to lymphoblast expansion and cytokine production (IFN-gamma, IL-2, and TNF), with the highest median magnitude detected after the second dose of vaccine. Stimulation with an overlapping peptide library based on structural TBE virus proteins E and C revealed that CD4(+) T cells concomitantly producing IL-2 and TNF dominated the responses from vaccinees after each vaccine dose, whereas a control cohort of TBE patients responded mainly with all three cytokines. CD107a expression was not upregulated upon peptide stimulation in the vaccinees. However, CD154 (CD40L) expression on cytokine-positive memory CD4(+) T cells significantly increased after the second vaccine dose. Taken together, TBE vaccination induced CD4(+) T cell responses dominated by IL-2 and TNF production together with CD154 upregulation and a lower IFN-gamma response compared with TBE patients. This response pattern was consistent after all three doses of TBE vaccine.
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| 7. |
- Albinsson, Bo, et al.
(författare)
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Distinction between serological responses following tick-borne encephalitis virus (TBEV) infection vs vaccination, Sweden 2017
- 2018
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Ingår i: Eurosurveillance. - 1025-496X .- 1560-7917. ; 23:3, s. 2-7
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Tidskriftsartikel (refereegranskat)abstract
- Tick-borne encephalitis virus (TBEV) is an important European vaccine-preventable pathogen. Discrimination of vaccine-induced antibodies from those elicited by infection is important. We studied anti-TBEV IgM/IgG responses, including avidity and neutralisation, by multiplex serology in 50 TBEV patients and 50 TBEV vaccinees. Infection induced antibodies reactive to both whole virus (WV) and non-structural protein 1 (NS1) in 48 clinical cases, whereas 47 TBEV vaccinees had WV, but not NS1 antibodies, enabling efficient discrimination of infection/vaccination.
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| 8. |
- Andersson, Håkan, et al.
(författare)
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Well-Tolerated Chemoprophylaxis Uniformly Prevented Swedish Soldiers from Plasmodium falciparum Malaria in Liberia, 2004-2006
- 2008
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Ingår i: Military medicine. - 0026-4075 .- 1930-613X. ; 173:12, s. 1194-1198
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Tidskriftsartikel (refereegranskat)abstract
- Background: Between 2004 and 2006, 1,170 Swedish soldiers were deployed to Liberia. They were prescribed mefloquine or atovaquone/proguanil as malaria chemoprophylaxis. Our study aims were to estimate the chemoprophylaxis effectiveness and adverse events. Methods: Cases of malaria were routinely reported during and after the mission. After return to Sweden, the soldiers filled in a questionnaire concerning type of accommodation, use of prophylaxis, and adverse events. Results: No cases of Plasmodium falciparum malaria were recorded during a total of 7,000 person-months. Adverse events (AE) were reported by 57% in the mefloquine group and 34% in the atovaquone/proguanil group. In the mefloquine group, the soldiers reported more neuropsychological AE. Conclusions: Both drugs were safe and 100% effective as lone-term prophylaxis for prevention of P. falciparum malaria. Atovaquone/proguanil was better tolerated with respect to self-reported AE.
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| 9. |
- Askling, Helena H., et al.
(författare)
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Hepatitis A Risk in Travelers
- 2009
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Ingår i: Journal of Travel Medicine. - : Oxford University Press (OUP). - 1195-1982 .- 1708-8305. ; 16:4, s. 233-238
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Tidskriftsartikel (refereegranskat)abstract
- Background Traveling to highly endemic areas for hepatitis A is increasing while the immunization level in travelers has been shown to be low in the countries studied. Methods In this population-based study, we have estimated the incidence rate of travel-related hepatitis A during 1997 to 2005 by use of the Swedish notification system of communicable diseases and an ongoing national database on travel patterns. We have also acquired airport-based immunization data from 2007. Results During the study period, 636 cases of travel-related hepatitis A were notified. Traveling to East Africa was associated with the highest incidence rate (14.1 cases/100,000 person months), followed by the Middle East (5.8/100,000 person months), and India with neighboring countries (5.6/100,000 person months). Visiting Friends and Relatives (VFR) travelers represented 83, 91, and 70% of the cases to these three regions. By age-group, the highest incidence was found in children 0 to 14 years (3.1/100,000 travelers) where 88% of the cases were VFR travelers. Incidence rate in unprotected travelers to East Asia, North Africa, and the Middle East was 2, 12, and 18 cases/100,000 person months, respectively. In 2007, 79% of the travelers were immunized against hepatitis A. Conclusions We conclude that travelers, and especially children, who are VFR in endemic areas constitute a high-risk group for acquiring hepatitis A infection, while the risk for unprotected tourists to East Asia is low.
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| 10. |
- Askling, Helena H., et al.
(författare)
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Hepatitis A vaccine for immunosuppressed patients with rheumatoid arthritis : a prospective, open-label, multi-centre study
- 2014
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Ingår i: Travel Medicine and Infectious Disease. - : Elsevier BV. - 1477-8939 .- 1873-0442. ; 12:2, s. 134-42
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hepatitis A vaccine is the most frequently used travel vaccine, yet data are scarce about its ability to induce protection in patients with concurrent immunosuppressive treatment. We assessed the immunogenicity of this vaccine in rheumatoid arthritis (RA) patients treated with tumour necrosis factor-inhibitors (TNFi) and/or methotrexate (MTX).METHODS: Hepatitis A vaccine was administered to non-immune RA patients at 0 and 6 months. Hepatitis A virus (HAV) antibodies were assessed at 0, 1, 6, 7, 12, and 24 months with a quantitative Chemiluminescent Microparticle Immuno Assay (CMIA) for HAV-IgG. Samples from month 1, 6, and 7 were, in addition, analysed with a microparticle EIA (MEIA) for anti-HAV IgM + IgG.RESULTS: The final study population consisted of 53 patients treated with TNFi (n = 15), TNFi + MTX (n = 21) or MTX (n = 17). One and six months after the first dose, 10% and 33% of the patients had attained seroprotection. One and six months after the second dose 83% and 72% were seroprotected. At month 24, 86% of the vaccinees showed protective levels.CONCLUSIONS: Two doses of hepatitis A vaccine at a 6-month interval provided protection for most immunosuppressed RA patients. A single dose does not seem to afford sufficient protection to this group of patients.
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