KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
Department of Infectious Diseases Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
Nat Commun. 2023 May 9;14(1):2666. doi: 10.1038/s41467-023-38277-z.
Pneumococcal conjugate vaccines (PCVs) protect against invasive pneumococcal disease (IPD) among vaccinees. However, at population level, this protection is driven by indirect effects. PCVs prevent nasopharyngeal acquisition of vaccine-serotype (VT) pneumococci, reducing onward transmission. Each disease episode is preceded by infection from a carrier, so vaccine impacts on carriage provide a minimum estimate of disease reduction in settings lacking expensive IPD surveillance. We documented carriage prevalence and vaccine coverage in two settings in Nigeria annually (2016-2020) following PCV10 introduction in 2016. Among 4,684 rural participants, VT carriage prevalence fell from 21 to 12% as childhood (<5 years) vaccine coverage rose from 7 to 84%. Among 2,135 urban participants, VT carriage prevalence fell from 16 to 9% as uptake rose from 15 to 94%. Within these ranges, carriage prevalence declined with uptake. Increasing PCV10 coverage reduced pneumococcal infection at all ages, implying at least a comparable reduction in IPD.
肺炎球菌结合疫苗 (PCV) 可预防疫苗接种者发生侵袭性肺炎球菌病 (IPD)。然而，在人群层面，这种保护作用是由间接效应驱动的。PCV 可预防鼻咽部携带疫苗血清型 (VT) 肺炎球菌，从而减少传播。每个疾病发作之前都有携带者感染，因此在缺乏昂贵的 IPD 监测的情况下，疫苗对带菌者的影响提供了疾病减少的最低估计。我们在 2016 年引入 PCV10 后，每年在尼日利亚的两个地区（2016-2020 年）记录了带菌率和疫苗覆盖率。在 4684 名农村参与者中，随着儿童（<5 岁）疫苗覆盖率从 7%上升到 84%，VT 带菌率从 21%下降到 12%。在 2135 名城市参与者中，随着疫苗接种率从 15%上升到 94%，VT 带菌率从 16%下降到 9%。在这些范围内，带菌率随接种率的增加而下降。PCV10 覆盖率的增加降低了所有年龄段的肺炎球菌感染，这意味着 IPD 的减少至少与之相当。
