Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Chittaganpich M[original query] |
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Does prior vaccination affect the immune response to seasonal influenza vaccination among older adults Findings from a prospective cohort study in a Northeastern Province of Thailand
Praphasiri P , Prasert K , Shrestha M , Ditsungnoen D , Chittaganpich M , Chawalchitiporn S , Dawood FS , Sirilak S , Mott JA . PLoS One 2023 18 (2) e0279962 BACKGROUND: We measured the immunogenicity of seasonal trivalent inactivated influenza vaccines (IIV3) among older Thai adults and the effect of one-year prior vaccination status on immune responses. METHOD: Adults aged ≥65 years (n = 370) were vaccinated with Southern Hemisphere IIV3 in 2015. Hemagglutination inhibition assays were performed using goose red blood cells on sera collected from the participants at baseline and after 1, 6, and 12 months of vaccination. Prior year vaccination (in 2014) was verified with the national health security office database. We analyzed the associations between prior vaccination and geometric mean titers (GMT) at each time point using generalized linear regression on logged transformed titers, and seroprotection and seroconversion using Log-binomial regression. RESULTS: At baseline, previously vaccinated participants (n = 203) had a significantly higher GMT and seroprotection against all three influenza strains than those previously unvaccinated (n = 167) (all p-values <0.001). Seroprotection rates were similar after one month in both groups for A(H1N1)pdm09 (adjusted risk ratio [aRR] 1.10, 95% CI 0.97-1.25), and A(H3N2) (aRR 1.08, 95% CI 0.87-1.33), but higher in previously vaccinated persons for B (aRR 1.20, 95% CI 1.08-1.32). At 12 months, 50% or more had seroprotection in previously vaccinated group with no difference between previously vaccinated or unvaccinated persons. Seroconversion was lower in the previously vaccinated group for A(H1N1)pdm09 (aRR 0.62, 95% CI 0.43-0.89), but did not differ between the two groups for A(H3N2) (aRR 0.94, 95% CI 0.69-1.28) and B (aRR 0.85, 95% CI 0.60-1.20). CONCLUSION: Influenza vaccination elicited good humoral response in older Thai adults. While seroconversion seemed attenuated in persons previously vaccinated for influenza A(H1N1)pdm09 (the only vaccine strain not to change), this was not apparent for influenza A(H3N2) and B, and prior vaccination was not associated with any inhibition in seroprotection. |
Effectiveness of trivalent inactivated influenza vaccine among community-dwelling older adults in Thailand: A two-year prospective cohort study
Prasert K , Patumanond J , Praphasiri P , Siriluk S , Ditsungnoen D , Chittaganpich M , Dawood FS , Mott JA , Lindblade KA . Vaccine 2019 37 (6) 783-791 BACKGROUND: We conducted a two-year prospective cohort study to measure the effectiveness of trivalent inactivated influenza vaccine (IIV3) to prevent laboratory-confirmed influenza among community-dwelling Thai adults aged >/=65years during 2015-16 and 2016-17 influenza seasons. METHODS: In 2015, we enrolled a cohort of 3220 participants. Trained health volunteers collected baseline data and followed participants for two years with weekly surveillance for new or worsened cough with self-collection of nasal swabs. Vaccine effectiveness (VE) was estimated as 100%x(1- rate ratio of rRT-PCR -confirmed influenza) among vaccinated versus unvaccinated participants. Propensity score stratification was used to reduce differences between vaccinated and unvaccinated participants associated with access to and receipt of IIV3. FINDINGS: During 2015-16 and 2016-17, 1666 (52%) and 1498 (48%) participants received IIV3, respectively. The overall incidence of influenza during the two seasons was 14.3/1000 person-years among vaccinated participants and 20.2/1000 person-years among unvaccinated participants. VE was -4% (95% confidence interval [CI], -83%-40%) during 2015-16 when there was poor antigenic match between the dominant circulating A/H3N2 viruses and the vaccine strain, and 50% (95% CI, 12-71%) during 2016-17 when circulating and vaccine strains were well-matched. Of all three influenza subtypes in both years, significant protection was observed only against Influenza A/H3N2 during 2016-17 (VE, 49%; 95% CI, 3-73%). INTERPRETATION: During a season with well-matched circulating and vaccine strains, IIV3 was moderately effective against laboratory-confirmed influenza among older adults in Thailand. |
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