Infection Prevention & Control Unit, Sheba Medical Center, Ramat-Gan, Israel; Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel.
Jerusalem-Shfela District, Maccabi Healthcare Services, Israel.
Vaccine. 2020 Apr 23;38(19):3591-3599. doi: 10.1016/j.vaccine.2020.03.016. Epub 2020 Mar 26.
S. pneumoniae carriage by children is a major source of pneumococcal transmission, and the initial step prior to infection. Pilus type 1, reported in ~30% of pneumococcal strains in the pre-vaccine era, contributes to pneumococcal colonization and virulence. In this study, we report the impact of the pneumococcal conjugate vaccine (PCV), PCV7/PCV13 sequential implementation on serotype distribution, and on the prevalence of piliated strains among carried pneumococci during the pre- and post-vaccine eras.
During 2002-2016, 12 repeated cross-sectional surveillances of nasopharyngeal S. pneumoniae carriage were conducted among 8,473 children <5.5 years old visiting primary care physicians in Central Israel. Seven biannual surveillances in the pre-PCV period, 2 surveillances after PCV7 was licensed but before implementation in the National Immunization Plan, and 3 additional surveillances in the post-PCV period. S. pneumoniae serotype distribution and prevalence of piliated strains were assessed.
Carriage of S. pneumoniae was relatively stable (45.4%). The prevalence of serotypes included in PCV13 was 65.7%, in the pre-vaccine period and the pilus was present in 26.4% of isolates. The distribution of serotypes and the pilus prevalence in the pre-PCV period was relatively stable except for a decrease in prevalence of piliated 19F, observed following the first study year. Following PCV7/PCV13 implementation, vaccine type 13 (VT13) strains were nearly eliminated to 3.3% by 2016. Piliated strains, which were primarily of VT13 serotypes, initially followed a similar trend and were nearly eliminated by 2014 (1.7%). Yet, two years later, pilus prevalence re-emerged among non-VT strains to 12.8% of all pneumococci.
Following PCV implementation, a dramatic and rapid decrease in VT strains prevalence was observed with a concomitant increase in non-VT strains. Piliated strains were nearly eliminated, yet re-emerged 7 years following PCV7/PCV13 implementation in various non-VT strains. This suggests that the pilus confers an advantage in colonization.
儿童携带肺炎链球菌是肺炎链球菌传播的主要来源，也是感染的初始步骤。在疫苗接种前，报告有大约 30%的肺炎链球菌菌株存在 1 型菌毛，它有助于肺炎链球菌定植和毒力。在这项研究中，我们报告了肺炎球菌结合疫苗（PCV）的影响，即 PCV7/PCV13 序贯实施对血清型分布的影响，以及在疫苗接种前和后时期，在携带肺炎球菌中流行的菌毛菌株的流行情况。
在 2002-2016 年期间，在以色列中部的 8473 名 5.5 岁以下儿童的初级保健医生处进行了 12 次反复的鼻咽部肺炎链球菌携带情况的横断面调查。在 PCV7 获得许可但尚未纳入国家免疫计划实施之前的 2 次半年度监测，以及在 PCV 接种后的 3 次监测。评估肺炎链球菌血清型分布和菌毛菌株的流行情况。
肺炎链球菌的携带率相对稳定（45.4%）。包括在 PCV13 中的血清型的流行率为 65.7%，在疫苗接种前，菌毛存在于 26.4%的分离株中。在疫苗接种前，血清型的分布和菌毛的流行率相对稳定，除了在第一个研究年度后，19F 菌毛的流行率下降。在实施 PCV7/PCV13 后，2016 年疫苗 13 型（VT13）菌株几乎被消除到 3.3%。菌毛菌株主要是 VT13 血清型，最初也遵循类似的趋势，到 2014 年几乎被消除（1.7%）。然而，两年后，非 VT 株的菌毛流行率重新上升到所有肺炎链球菌的 12.8%。
在实施 PCV 后，观察到 VT 菌株的流行率急剧快速下降，同时非 VT 菌株的流行率增加。菌毛菌株几乎被消除，但在 PCV7/PCV13 实施 7 年后，在各种非 VT 菌株中再次出现。这表明菌毛有助于定植。
