From the Department of Microbiology.
Department of Microbiology and Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama.
Pediatr Infect Dis J. 2020 Apr;39(4):298-304. doi: 10.1097/INF.0000000000002581.
Polysaccharide conjugate vaccines (PCVs) target the pneumococcal capsular types that most commonly cause fatal pneumonia and sepsis. Because these types were eliminated by the vaccines, it became apparent that in immunized populations, most invasive pneumococcal diseases, including bacteremia, sepsis and complicated pneumonia, were greatly reduced. However, the protective effects of PCVs against another invasive disease, meningitis, has shown much less or no decrease in disease incidence.
References were identified through searches of PubMed for articles published from January 1930 to the present by use of specific search terms. Relevant articles were also identified through searches in Google and Google Scholar. Relevant references cited in those articles were also reviewed.
Even in the presence of the PCVs, meningitis rates in children have been reported globally to be as high as 13 per 100,000 annually. Widespread use of vaccines resulted in the emergence of a broad diversity of replacement non-PCV type strains. These strains generally failed to cause sepsis, but caused meningitis of comparable severity and levels similar to, or in excess of, prior pneumococcal meningitis rates. This is probably because these non-PCV type strains do not survive well in the blood, therefore possibly entering the brain through nonhematogenous routes.
Because virtually all cases of pneumococcal meningitis lead to either permanent neurologic sequelae or death, it would be well worth the effort to develop a new vaccine capable of preventing pneumococcal meningitis regardless of capsular type. Such a vaccine would need to protect against colonization with most, if not all, pneumococci.
多糖结合疫苗（PCV）针对的是最常见导致致命性肺炎和败血症的肺炎球菌荚膜型。由于这些类型已被疫苗消除，因此很明显，在免疫人群中，大多数侵袭性肺炎球菌病，包括菌血症、败血症和复杂性肺炎，大大减少。然而，PCV 对另一种侵袭性疾病——脑膜炎的保护作用显示，疾病发病率的下降幅度较小或没有下降。
通过使用特定的搜索词，在 PubMed 上搜索从 1930 年 1 月到现在发表的文章，确定参考文献。还通过在 Google 和 Google Scholar 中搜索来确定相关文章。还查阅了这些文章中引用的相关参考文献。
即使存在 PCV，全球儿童的脑膜炎发病率仍高达每年每 10 万人中有 13 例。疫苗的广泛使用导致了广泛的替代非 PCV 型菌株的出现。这些菌株通常不会引起败血症，但会引起脑膜炎，其严重程度和水平与以前的肺炎球菌脑膜炎率相当，甚至超过。这可能是因为这些非 PCV 型菌株在血液中不能很好地存活，因此可能通过非血源性途径进入大脑。
由于几乎所有的肺炎球菌性脑膜炎病例都会导致永久性神经后遗症或死亡，因此，开发一种能够预防肺炎球菌性脑膜炎的新疫苗将是非常值得的，无论荚膜类型如何。这种疫苗需要能够预防大多数（如果不是全部）肺炎球菌的定植。
