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Background: Healthcare workers (HCWs) are an important target group for influenza vaccination due to their increased risk of infection. However, their uptake remains a challenge. This study aimed to identify and measure influenza vaccine hesitancy among HCWs in Nakhon Phanom province, Thailand. Methods: A representative cross-sectional survey was conducted during August–September 2020, among 350 HCWs at six hospitals in the province selected by a two-stage cluster sampling using a self-administered questionnaire. HCWs who either delayed getting influenza vaccines, accepted the vaccines but were unsure, or refused the vaccine with doubts were categorized as hesitant. HCWs who accepted the influenza vaccine without any doubts were classified as non-hesitant. Determinants of vaccine hesitancy were identified by a multivariable logistic regression analysis. Results: A total of 338 participants (97%) filled the questionnaires. The mean age of the participants was 37.2 years. Most participants were female (280; 83%), nurses (136; 40%), working at district hospitals (238; 71%), with bachelor's degree (223; 66%), and without any pre-existing chronic medical conditions (264; 78%). Influenza vaccine hesitancy was evident among nearly 60% of the participants (197/338), who had varying patterns of hesitancy. Significant factors of influenza vaccine hesitancy were found to be age above 50 years (adjusted odds ratio [aOR] 3.2, 95% CI 1.3–8.5), fair knowledge of influenza and vaccination (aOR 0.4, 95% CI 0.2–0.8), and negative influence of other HCW (High level–aOR 2.3, 95% CI 1.1–4.8; Moderate level- aOR 2.1, 95% CI 1.1–4.4). Conclusion: Influenza vaccine hesitancy was highly prevalent among the Thai HCWs in Nakhon Phanom province. Imparting updated information to the HCW, in combination with positive guidance from influential HCWs in the hospital, may help reduce hesitancy. These data may be useful to the National Immunization Program to design appropriate approaches to target hesitant HCWs in Thailand to improve influenza vaccine coverage. [ABSTRACT FROM AUTHOR]

Domestic influenza vaccine production facilitates a sustainable supply for mitigating seasonal influenza and improves national health security by providing infrastructure and experience for pandemic vaccine production, if needed. A Phase III, double blind, randomized controlled trial was conducted from Sep 2019-Oct 2020 in healthy adults 18–64 years in Nakhon Phanom, Thailand. Randomization (3:3:1) compared study vaccine (Tri Fluvac), saline placebo, and an active comparator (licensed vaccine). Primary outcomes were superior efficacy compared to placebo based on RT-PCR-confirmed influenza virus infection within 12 months and non-inferiority compared to active comparator based on immunogenicity (HAI assay) at 28 days. Safety was also assessed. The trial enrolled 4,284 participants (Tri Fluvac = 1,836; placebo = 1,836; active comparator = 612). There were 29 RT-PCR positive influenza infections (10 Tri Fluvac, 5.5/1,000 PY; 19 placebo, 10.4/1,000PY; 0 comparator) for an absolute protective efficacy of 46.4 (95 % CI = −22.0–76.5) compared with placebo, but the power was 43.7 %. Seroconversion difference rates between Tri Fluvac and comparator at Day 28 were 1.74 (95 % CI: −2.77, 6.25), 2.22 (−2.40, 6.84), and −0.57 (−5.41, 4.27) for A(H1N1), A(H3N2), and B strains, respectively. Adverse and severe adverse events occurred in 175 (9.5 %) Tri Fluvac, 177 (10.8 %) placebo, and 66 (10.8 %) comparator arms (p-value = 0.437, Tri Fluvac vs. comparator) Tri Fluvac was well tolerated, and immunogenicity was non-inferior to the active comparator, meeting U.S. Food and Drug Administration (FDA) criteria for adult vaccine licensure. Few acute respiratory infections were reported during intense COVID-19 pandemic restrictions, resulting in insufficient power to evaluate clinical efficacy. [ABSTRACT FROM AUTHOR]

Streptococcus suis, a zoonotic pathogen found primarily in pigs, can cause serious infection in humans. Most cases in human occur in Southeast Asia, where pig rearing is common (1). In [...]

Background. Individuals infected with human immunodeficiency virus (HIV) are at increased risk for severe influenza, yet immune responses to standard-dose intramuscular (IM) influenza vaccine are suboptimal in this population. Intradermal (ID) delivery of influenza vaccine might improve immune response through enhanced stimulation of dendritic cells. Methods. We conducted a randomized, double-blind, controlled trial to compare the immunogenicity of off-label standard-dose (15 μg) ID vs standard-dose (15 μg) IM inactive influenza vaccine in HIV-infected men in Bangkok, Thailand. The primary study outcome was seroconversion (minimum titer of 1:40 and ≥4-fold rise in antibody titer) at 1 month postvaccination based on serum hemagglutination inhibition antibody titers against each vaccine strain. Adverse events (AEs) in the 7 days following vaccination were also assessed. Results. We enrolled 400 HIV-infected participants; 200 were randomly assigned to receive IM and 200 ID vaccine. Vaccine arms were well-balanced with respect to age, CD4 cell count, HIV RNA load, and antiretroviral treatment. Percentage of seroconversion to all (ID 14% vs IM 15%; P = .8) or at least 1 (ID 69% vs IM 68%; P = .7) of the 3 vaccine strains did not differ significantly between ID vs IM vaccine recipients. A higher proportion of participants who received ID vaccine had mild injection-site AEs compared with participants who received IM vaccine (77% vs 27%). Conclusions. There were no significant differences in the immunogenicity of standard-dose ID vs IM influenza vaccine in this HIVinfected population in Thailand. Additional strategies to enhance immune responses to influenza vaccine among HIV-infected persons are needed. [ABSTRACT FROM AUTHOR]