Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
Royal Liverpool University Hospital, Liverpool, United Kingdom.
Vaccine. 2019 Jul 9;37(30):3953-3956. doi: 10.1016/j.vaccine.2019.05.080. Epub 2019 Jun 5.
Widespread use of Pneumococcal Conjugate Vaccines (PCV) has reduced vaccine-type nasopharyngeal colonisation and invasive pneumococcal disease. In a double-blind, randomised controlled trial using the Experimental Human Pneumococcal Challenge (EHPC) model, PCV-13 (Prevenar-13) conferred 78% protection against colonisation acquisition and reduced bacterial intensity (AUC) as measured by classical culture. We used a multiplex qPCR assay targeting lytA and pneumococcal serotype 6A/B cpsA genes to re-assess the colonisation status of the same volunteers. Increase in detection of low-density colonisation resulted in reduced PCV efficacy against colonisation acquisition (29%), compared to classical culture (83%). For experimentally colonised volunteers, PCV had a pronounced effect on decreasing colonisation density. These results obtained in adults suggest that the success of PCV vaccination could primarily be mediated by the control of colonisation density. Studies assessing the impact of pneumococcal vaccines should allow for density measurements in their design.
肺炎球菌结合疫苗（PCV）的广泛使用降低了疫苗型鼻咽定植和侵袭性肺炎球菌病。在使用实验性人体肺炎球菌挑战（EHPC）模型的双盲、随机对照试验中，PCV-13（沛儿 13）对定植获得的保护率为 78%，并通过经典培养降低了细菌强度（AUC）。我们使用靶向 lytA 和肺炎球菌血清型 6A/B cpsA 基因的多重 qPCR 检测方法重新评估了相同志愿者的定植状态。低密度定植检测的增加导致 PCV 对定植获得的疗效降低（29%），而经典培养为（83%）。对于实验性定植的志愿者，PCV 对降低定植密度有显著作用。这些在成年人中获得的结果表明，PCV 疫苗接种的成功可能主要通过控制定植密度来介导。评估肺炎球菌疫苗影响的研究应在其设计中允许进行密度测量。
