肺炎链球菌能够引发肺炎、脑膜炎和菌血症发热等严重疾病,也能引发较轻和常见的中耳炎、鼻窦炎和支气管炎等疾病。目前肺炎结合疫苗只有7价结合疫苗(PCV-7),PCV-7在欧美可以覆盖65%~80%的致病性肺炎链球菌血清型,在发展中国家的覆盖率较低。PCV-7能够诱导T-细胞依赖免疫反应,加 Streptococcus pneumoniae can cause serious diseases such as pneumonia, meningitis and bacteremia fever, but also can cause mild and common otitis media, sinusitis and bronchitis and other diseases. Currently, the pneumococcal conjugate vaccine has only a 7-valent conjugate vaccine (PCV-7). PCV-7 can cover 65% to 80% of the pathogenic S. pneumoniae serotypes in Europe and the United States, with a relatively low coverage in developing countries. PCV-7 is able to induce T-cell-dependent immune responses plus