Tin Tin Htar Myint, Christopoulou Dina, Schmitt Heinz-Josef
Pfizer Vaccines, Medical Development Group and Scientific Affairs, 23-25 avenue du Dr. Lannelongue, F-75668, Paris, Cedex 14, France.
BMC Infect Dis. 2015 Oct 14;15:419. doi: 10.1186/s12879-015-1147-x.
Pneumococcal diseases remain a leading cause of vaccine-preventable death worldwide in children <5 years of age. The seven-valent pneumococcal conjugate vaccine (PCV7) was approved in 2001 in Europe and was introduced into the national immunization programmes of many European countries from 2006-2008. In 2009, higher-valent PCVs (PCV10 and PCV13) became available, replacing PCV7 from 2009-2011. This article describes the evolution of vaccine and non-vaccine serotypes causing invasive pneumococcal disease (IPD) following the introduction of PCVs in Western Europe, based on data from publicly-available medical publications and national surveillance systems from January 2010 to May 2015.
In countries with high vaccine uptake, 5-7 years after PCV7 introduction IPD caused by vaccine serotypes has almost disappeared in children. Non-PCV7 serotypes have emerged, particularly serotypes 19A, 7 F, 3 and 1. A rapid and significant reduction of the additional serotypes included in higher-valent vaccines has been observed consistently following the introduction of these vaccines. A significant and rapid decline of serotypes 19A, 7 F, 1 and 6A in both vaccine-eligible and older age groups has been observed in countries using PCV13 while serotype 19A and 3 has increased in countries using PCV10. Serotype 3 has become one of the most prevalent serotypes in adults, with some reduction only in the UK and France. Serotype diversity increased and varied by age group, the type of vaccine in use, and the time since the introduction of higher-valent PCVs. Serotypes that are currently more frequent include 24 F, 22 F, 8 and 15A in countries that use PCV13, and serotypes 19A and 3 in countries that use PCV10. Compared with the time before the introduction of higher valent PCVs, to date, there is no single '19A-like' serotype emerging across countries and most of the newly emerging non-PCV13 vaccine types are less invasive with a low case-carrier ratio.
It is important to closely monitor not only evolving serotypes but also the magnitude of the effect in order to evaluate the overall impact of pneumococcal vaccination programmes and to initiate the appropriate vaccination strategy. Emerging serotypes may also need to be considered for the future development of new vaccines.
肺炎球菌疾病仍是全球5岁以下儿童中疫苗可预防死亡的主要原因。七价肺炎球菌结合疫苗（PCV7）于2001年在欧洲获批，并于2006年至2008年被纳入许多欧洲国家的国家免疫规划。2009年，更高价的肺炎球菌结合疫苗（PCV10和PCV13）上市，从2009年至2011年取代了PCV7。本文基于2010年1月至2015年5月公开的医学出版物和国家监测系统的数据，描述了西欧引入肺炎球菌结合疫苗后引起侵袭性肺炎球菌疾病（IPD）的疫苗血清型和非疫苗血清型的演变情况。
在疫苗接种率高的国家，引入PCV7后的5至7年里，由疫苗血清型引起的儿童IPD几乎消失。非PCV7血清型出现了，尤其是19A、7F、3和1血清型。在引入更高价疫苗后，一直观察到更高价疫苗中包含的其他血清型迅速且显著减少。在使用PCV13的国家，在符合疫苗接种条件的年龄组和 older age groups中，19A、7F、1和6A血清型显著且迅速下降，而在使用PCV10的国家，19A和3血清型有所增加。3血清型已成为成人中最常见的血清型之一，仅在英国和法国有所减少。血清型多样性增加，且因年龄组、所用疫苗类型以及引入更高价肺炎球菌结合疫苗后的时间而异。在使用PCV13的国家，目前更常见的血清型包括24F、22F、8和15A，在使用PCV10的国家，血清型为19A和3。与引入更高价肺炎球菌结合疫苗之前的时期相比，迄今为止，各国并未出现单一的“19A样”血清型，大多数新出现的非PCV13疫苗类型侵袭性较低，病例携带率也较低。
密切监测不仅血清型的演变，还要监测其影响程度，对于评估肺炎球菌疫苗接种计划的总体影响以及启动适当的疫苗接种策略非常重要。新出现的血清型在未来新疫苗的研发中也可能需要考虑。
