| 1. |
- Erra, Elina O, et al.
(författare)
-
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
-
Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 55:6, s. 825-834
-
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.
|
|
| 2. |
- Pakkanen, Sari H, et al.
(författare)
-
Specific and cross-reactive immune response to oral Salmonella Typhi Ty21a and parenteral Vi capsular polysaccharide typhoid vaccines administered concomitantly
- 2015
-
Ingår i: Vaccine. - : Elsevier BV. - 0264-410X .- 1873-2518. ; 33:3, s. 451-8
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Since protective efficacy of the current typhoid vaccines-oral whole-cell Salmonella Typhi Ty21a and parenteral Vi-capsular polysaccharide preparation-is not optimal, and no vaccines are available against paratyphoid or non-typhoidal Salmonella (NTS) serotypes, new approaches deserve to be explored. The immunological mechanisms elicited by the two typhoid vaccines are mainly targeted against different structures. We studied whether these vaccines would enhance S. Typhi-specific immune response and cross-reactivity against other Salmonellae, if administered concomitantly.MATERIALS AND METHODS: Volunteers were immunized simultaneously with Ty21a and Vi vaccines (Ty21a+Vi group) or with either of the two singly (Ty21a and Vi groups). All volunteers were investigated for circulating specific and cross-reactive plasmablasts, identified by ELISPOT as IgA, IgG or IgM antibody-secreting cells (ASC) reactive with S. Typhi, S. Paratyphi A/B/C, or selected NTS serotypes (S. Enteritidis, S. Typhimurium).RESULTS: In the Ty21a+Vi group, no specific or cross-reactive plasmablasts were detected before vaccination. After vaccination, the number of S. Typhi-specific plasmablasts (878 ASC/10(6) PBMC, 95%CI 554-1201) proved higher than in the Ty21a (339 ASC/10(6) PBMC; p<0.001) and Vi (149 ASC/10(6) PBMC; p<0.001) groups. Likewise, cross-reactive responses in the Ty21a+Vi group were higher than in the Ty21a and Vi groups (Ty21a+Vi vs Ty21a: ASC against S. Paratyphi A/B, S. Enteritidis and S. Typhimurium p<0.05, against S. Paratyphi C p<0.01; Ty21a+Vi vs Vi: against S. Paratyphi C not significant, others p<0.0001). A gut-directed homing profile was seen among O antigen-specific and a systemic one among Vi antigen-specific plasmablasts.CONCLUSIONS: Concomitant administration of Ty21a and Vi vaccines is well tolerated and induces an additive immune response to the two vaccines. Thus it enhances the magnitude of both typhoid-specific plasmablast responses and those cross-reacting with paratyphoid and most important NTS serotypes. The data encourage concomitant use of Ty21 and Vi vaccines for those at risk.
|
|
| 3. |
- Riekkinen, Marianna, et al.
(författare)
-
Coadministered pneumococcal conjugate vaccine decreases immune response to hepatitis A vaccine : a randomized controlled trial
- 2023
-
Ingår i: Clinical Microbiology and Infection. - : Elsevier. - 1198-743X .- 1469-0691. ; 29:12, s. 1553-1560
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: We explored the influence of coadministration on safety and immunogenicity of the most common travellers' vaccine hepatitis A (HepA) and the pneumococcal conjugate vaccine (PCV) increasingly used both at home and before travel.Methods: Volunteers aged >= 18 years (n = 305) were randomly assigned 1:1:1 into three groups receiving: 13-valent PCV (PCV13) + HepA, PCV13, or HepA. Anti-pneumococcal IgG concentrations, opsonophagocytic activity (OPA) titres, and total hepatitis A antibody (anti-HAV) concentrations were measured before and 28 +/- 3 days after vaccination. Adverse events (AEs) were recorded over 4 weeks.Results: After vaccination, the anti-HAV geometric mean concentration was significantly lower in the PCV13+HepA than the HepA group: 34.47 mIU/mL (95% CI: 26.42-44.97 mIU/mL) versus 72.94 mIU/mL (95% CI: 55.01-96.72 mIU/mL), p < 0.001. Anti-HAV >= 10 mIU/mL considered protective was reached by 71 of 85 (83.5%) in the PCV13+HepA group versus 76 of 79 (96.2%) in the HepA group, p 0.008. The increases in anti-pneumococcal IgG and OPA levels were comparable in the PCV13+HepA and PCV13 groups, apart from a bigger rise in the PCV13+HepA group for serotype 3 (one-way ANOVA: serotype 3 IgG p 0.010, OPA p 0.002). AEs proved more frequent among those receiving PCV13 than HepA, but simultaneous administration did not increase the rates: >= one AE was reported by 45 of 56 (80.4%) PCV13, 43 of 54 (79.6%) PCV13+HepA, and 25 of 53 (47.2%) HepA recipients providing structured AE data.Discussion: Coadministration of HepA and PCV13 did not cause safety concerns, nor did it impact the patients' response to PCV13, apart from serotype 3. However, coadministered PCV13 significantly impaired antibody responses to HepA.
|
|
