Efficacy and effectiveness of extended-valency pneumococcal conjugate vaccines

Abstract

The 7-valent pneumococcal protein conjugate vaccine (PCV7) has been shown to be highly efficacious against invasive pneumococcal diseases and effective against pneumonia and in reducing otitis media. The introduction of PCV7 has resulted in major changes in the epidemiology of pneumococcal diseases. However, pneumococcal vaccines induce serotype-specific immunity, and a relative increase in non-vaccine serotypes has been reported following the widespread use of PCV7, leading to a need for extended serotype coverage for protection. PCV10 and PCV13 have been licensed on the basis of noninferiority of immunogenicity compared to a licensed conjugate vaccine. In this article, we aimed to review important data regarding the efficacy and effectiveness of the extended-coverage PCVs published or reported thus far and to discuss future implications for pneumococcal vaccines in Korea. After the introduction of PCV10 and PCV13, within a short period of time, evidence of protection conferred by these vaccines against invasive and mucosal infections caused by most of the serotypes included in the vaccines is accumulating. The choice of vaccine should be based on the changes in the dynamics of pneumococcal serotype distribution and diseases in the region where the vaccines are to be used. Continuous surveillance is essential for the appropriate use of pneumococcal vaccines and evaluation of the impact of PCVs on pneumococcal diseases.

Keywords: 10-valent pneumococcal vaccine; 13-valent pneumococcal vaccine; Pneumococcal vaccines.

Fig. 1

Changes in invasive pneumococcal disease incidence among 8 children's hospitals in the United States after the introduction of the 13-valent pneumococcal protein conjugate vaccine (PCV13). PCV7, 7-valent pneumococcal protein conjugate vaccine; PCV10, 10-valent pneumococcal protein conjugate vaccine. Adapted from Kaplan SL, et al. Pediatr Infect Dis J 2013;32:203-7.

Fig. 2

Distribution of serotypes among 140 invasive pneumococcal isolates in children in Korea by year, 2006-2010. In the trend analysis, PCV7 serotypes significantly decreased over time (from 62.5% to 21.4%, P=0.002), whereas 3 PCV13-specific serotypes increased (from 18.8% to 42.9%, P=0.016). PCV7, 7-valent pneumococcal protein conjugate vaccine; PCV10, 10-valent pneumococcal protein conjugate vaccine; PCV13, 13-valent pneumococcal protein conjugate vaccine. Adapted from Cho EY, et al. Diagn Microbiol Infect Dis Forthcoming 2014.