Streptococcus pneumoniae serotype 19A: worldwide epidemiology

Abstract

Streptococcus pneumoniae causes mucosal and invasive diseases with high morbidity and mortality. Introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) into routine infant immunization programs worldwide resulted in serotype 19A becoming a leading cause of the remaining pneumococcal disease burden in vaccinated and nonvaccinated individuals. This article reviews the impact of the latest generation PCVs (10-valent PCV, PCV10, and 13-valent PCV, PCV13) on serotype 19A. Areas covered: This article covers immune responses elicited by PCV7, PCV10 and PCV13 against serotype 19A and their impact on nasopharyngeal (NP) carriage and disease in vaccinated and unvaccinated populations using data from surveillance systems, randomized controlled trials, and observational studies. Expert commentary: As expected from a PCV containing serotype 19A, PCV13 elicits significantly higher functional immune responses against serotype 19A than PCV7 and PCV10. Higher responses are likely to be linked to both direct impact in vaccinated populations and reductions in 19A NP carriage in children, thus inducing herd protection and reducing 19A invasive pneumococcal disease (IPD) in nonvaccinated children and adults. In contrast, PCV7 and PCV10 have shown mixed evidence of direct short-lived cross-protection and little to no impact on 19A carriage, resulting in continued transmission and disease.

Comment on Gomez et. al. “Response to article by Wasserman et. al. (2018) ‘Modelling the sustained use of the 13-valent pneumococcal conjugate vaccine compared to switching to the 10-valent vaccine in Mexico’”

“…For example, any changes in 19A disease due to cross-reactivity would be captured in surveillance data in PCV10 countries. However, because PCV10 does not provide protection against 19A pneumococcal carriage, 4 rates of 19A disease have been increasing at a population level in both vaccinated and unvaccinated populations in countries using PCV10 and recent studies have stated that PCV10 provides limited cross-reactivity with 19A. 5 Furthermore, Gomez and colleagues state that SIREVA have shown a reduction in 19A after PCV13 use, 6 but it still circulates, which is consistent with Figure 2 in our manuscript, as 19A cases have continue to persist in the PCV13 arm even at the 10 year time horizon.…”

Theoretical Background and Real Results: A Data Review on Vaccine Prevention of Pneumococcal Infection in the World

“…Еще на примере ПКВ7 было показано, что, несмотря на наличие достаточно высокой концентрации перекрестных антител к 19А, полученных за счет вве-дения вакцины, содержащей лишь 19F, эти антитела не ведут к оптимальному опсонофагоцитозу. Аналогичные результаты были получены и для ПКВ10, пусть и с дву-кратным нарастанием титра опсонофагоцитарной актив-ности по сравнению с ПКВ7 [24,33,47]. Некоторыми авторами определен серологический коррелят защиты против ИПИ, вызываемых серотипом 19А, на уровне 1,0 мкг/мл, не достигаемый при иммунизации ПКВ10 [48].…”

“…Так, во Франции, Норвегии и Швейцарии через 1-2 года внедрения ПКВ13 в рутинный график иммунизации распространенность ИПИ, связанных с вак-циноспецифичными серотипами, составляла 42-62%, тогда как в Великобритании через 4 года использования ПКВ13 -только 21% [47].…”

Pneumococcal Vaccine as One of the Immunization Coverage Targets For Adulthood Vaccines: A Consensus Report of the Study Group For Adult Immunization of the Turkish Society of Clinical Microbiology and Infectious Diseases

“…KPA7'de bulunmayan ancak KPA13'e eklenen S. pneumoniae serotip 19A'nın, invazif olması ve "multidrug resistant" (MDR) olma eğilimi göstermesi nedeniyle, İPH epidemiyolojisinde özel bir yeri vardır (22,116,117). KPA7'yi ulusal bağı-şıklama programlarına dahil eden ülkelerde, üniversal aşıla-madan birkaç yıl sonra duyarlı olmayan 19A ve MDR 19A'nın neden olduğu İPH olgularında artış gözlenmektedir.…”

“…Öte yandan, KPA7'nin uygulamaya girmediği ya da yaygın olarak kullanılmadığı Asya ülkelerinde de serotip 19A ve bunun MDR klonlarının (ST-320 izolatları gibi) bir artış eğilimi gös-terdiği bildirilmiştir (34). Ayrıca, ne KPA13'te ne de PPA23'te bulunan ve önemli ölçüde antibiyotik direnci sergileyen 15B, 23A, 23B ve 35B gibi serotipler de KPA13'ün kullanıma girmesinden sonra ortaya çıkmıştır (116)(117)(118).…”