关注肺炎链球菌结合疫苗应用后的血清型替换现象

Review on the serotype replacement after universal administration of pneumococcal conjugated vaccine

肺炎链球菌是人类感染性疾病的重要病原,尤其对于儿童和老年人。目前针对儿童开发应用的是7价蛋白多糖结合疫苗(PCV7:4、6B、9V、14、18C、19F和23F)。美国等推广PCV7应用后,肺炎链球菌侵袭性疾病显著减少;同时,非疫苗血清型定植、致病增多,在分离株中所占比例升高,该现象称为血清型替换(serotypere placement)。某些单个非疫苗血清型导致的侵袭性疾病发病率已经呈现明显上升,如3、19A、22F和33F型,某些非疫苗血清型菌株的抗生素耐药性也增强。可以通过增加结合疫苗的血清型和研发对所有血清型均可提供保护的通用疫苗来应对血清型替换。

Streptococcus pneumonia is the most common cause of infective diseases in human, especially in young children and older adults. A vaccine consisting of seven capsular polysaccharides （serotype 4, 6B, 9V, 14, 18C, 9F and 23F） conjugated to protein was introduced for young children. The prevalence of invasive pneumococcal disease decreased significantly after universal immunization of PCV7 in United States and other countries. At the same time, the number or proportion of pneumococcal isolates expressing nonvaccine serotype increased, which was named as serotype replacement. There have been significant increases in invasive pneumococcal disease by individual nonvaccine serotypes, such as 3, 19A, 22F and 33F. Futhermore, the antibiotic resistance of some nonvaccine serotypes isolates was potentized. For keeping the immunization effects, it is necessary to expand the serotype formulation of conjugated pneumococcal vaccine and to develop vaccines that provide protection against all serotypes.