Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.
Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India.
Influenza Other Respir Viruses. 2023 Jun;17(6):e13149. doi: 10.1111/irv.13149.
We present post-vaccination nasal shedding findings from the phase IV, community-based, triple-blinded RCT conducted to assess efficacy of trivalent LAIV and inactivated influenza vaccines in rural north India.
Children aged 2-10 years received LAIV or intranasal placebo across 2015 and 2016, as per initial allocation. On days 2 and 4 post-vaccination, trained study nurses collected nasal swabs from randomly selected subset of trial participants based on operational feasibility, accounting for 10.0% and 11.4% of enrolled participants in 2015 and 2016, respectively. Swabs were collected in viral transport medium and transported under cold chain to laboratory for testing by reverse transcriptase real-time polymerase chain reaction.
In year 1, on day 2 post-vaccination, 71.2% (74/104) of LAIV recipients shed at least one of vaccine virus strains compared to 42.3% (44/104) on day 4. During year 1, on day 2 post-vaccination, LAIV-A(H1N1)pdm09 was detected in nasal swabs of 12% LAIV recipients, LAIV-A(H3N2) in 41%, and LAIV-B in 59%. In year 2, virus shedding was substantially lower; 29.6% (32/108) of LAIV recipients shed one of the vaccine virus strains on day 2 compared to 21.3% on day 4 (23/108).
At day 2 post-vaccination in year 1, two-thirds of LAIV recipients were shedding vaccine viruses. Shedding of vaccine viruses varied between strains and was lower in year 2. More research is needed to determine the reason for lower virus shedding and vaccine efficacy for LAIV-A(H1N1)pdm09.
我们报告了在印度北部农村进行的四期、基于社区的、三盲 RCT 的疫苗接种后鼻腔脱落研究结果，旨在评估三价 LAIV 和灭活流感疫苗的疗效。
2015 年和 2016 年，2-10 岁的儿童按初始分配接受 LAIV 或鼻内安慰剂。接种后第 2 天和第 4 天，根据操作可行性，训练有素的研究护士从试验参与者中随机选择部分参与者收集鼻腔拭子，分别占 2015 年和 2016 年入组参与者的 10.0%和 11.4%。拭子用病毒转运培养基收集，并在冷链下运送到实验室，通过逆转录实时聚合酶链反应进行检测。
在第 1 年，接种后第 2 天，71.2%（74/104）的 LAIV 接种者至少有一种疫苗病毒株脱落，而第 4 天为 42.3%（44/104）。在第 1 年，接种后第 2 天，LAIV-A(H1N1)pdm09 在 12%的 LAIV 接种者的鼻腔拭子中检测到，LAIV-A(H3N2)为 41%，LAIV-B 为 59%。在第 2 年，病毒脱落量明显较低；接种后第 2 天，LAIV 接种者中有 29.6%（32/108）有一种疫苗病毒株脱落，第 4 天为 21.3%（23/108）。
在第 1 年接种后第 2 天，三分之二的 LAIV 接种者正在脱落疫苗病毒。不同菌株之间的病毒脱落情况不同，第 2 年的病毒脱落量较低。需要进一步研究以确定 LAIV-A(H1N1)pdm09 病毒脱落减少和疫苗效力降低的原因。
