Pneumococcal Conjugate Vaccine Impact on Serotype 3: A Review of Surveillance Data

Abstract

Introduction Limited changes in serotype 3 invasive pneumococcal disease (IPD) incidence rates after a decade of 13-valent pneumococcal conjugate vaccine (PCV13) introduction into several national immunization programs (NIP) have raised questions about PCV13's effectiveness against this serotype. Methods We analyzed the impact of pediatric PCV programs on serotype 3 IPD with two approaches. First, we reviewed the publicly available surveillance data from countries identified in two recently published reviews to describe the population impact of pediatric PCV13 or PCV10 vaccination programs on serotype 3 IPD. We then compared the observed trends in PCV10 and PCV13 countries to a previously described dynamic transmission model that simulates the spread of pneumococcal carriage and development of IPD in a population over time. Results When serotype 3 disease rates are compared from countries that have introduced either a 10-valent (PCV10) vaccine that does not contain serotype 3 in its formulation or PCV13 in their pediatric NIP, over time, serotype 3 incidence rate trends are markedly different. Countries with a PCV10 NIP showed a substantial linear increase in serotype 3 pneumococcal disease among all age groups since the time of PCV10 introduction, whereas countries with a PCV13 NIP experienced a modest decline during the 3–4 years after vaccine introduction followed by an inflection upward in subsequent years. Conclusion These data suggest that PCV13 provides a certain degree of direct and indirect protection against serotype 3 at the population level and direct adult vaccination with a serotype 3-containing vaccine is likely to provide substantial benefit in the context of a pediatric PCV NIP. Further research around serotype 3 transmission patterns and epidemiology is nonetheless warranted. Supplementary Information The online version contains supplementary material available at 10.1007/s40121-021-00406-w.

Pediatric Invasive Pneumococcal Disease Three Years after PCV13 Introduction in the National Immunization Plan—The Continued Importance of Serotype 3

“…All these results seem to support the lower effectiveness of PCV13 against serotype 3 complicated pneumonia, although unexplained geographical differences persist [ 29 ]. The reasons behind these differences could be related to different vaccination schedules, risk factors, natural trends, differences in sampling or transmission dynamics, as already suggested to account for other differences in serotype replacement [ 29 , 30 ]. Differences in the etiologic diagnosis methods could potentially further affect the results since the use of molecular methods to complement culture is essential to avoid underestimating this important serotype in the epidemiology of pIPD.…”

“…In Germany, after the introduction of PCV13, and in a situation of high vaccination coverage, serotype 3 pneumonia with parapneumonic pleural effusion or empyema increased and a considerable number of vaccine failures were associated with this serotype [11]. All these results seem to support the lower effectiveness of PCV13 against serotype 3 complicated pneumonia, although unexplained geographical differences persist [29]. The reasons behind these differences could be related to different vaccination schedules, risk factors, natural trends, differences in sampling or transmission dynamics, as already suggested to account for other differences in serotype replacement [29,30].…”

PCV13 Vaccination of Adults against Pneumococcal Disease: What We Have Learned from the Community-Acquired Pneumonia Immunization Trial in Adults (CAPiTA)

“…Totality of Data Are Consistent with PCV13 Efficacy against Serotype 3 Similar to the Overall PCV13 Efficacy PCV13 has been introduced into pediatric national immunization programs in many countries globally with high uptake and in the USA and other countries also with programs targeting older adults [34,35]. Nevertheless, serotype 3 continues to be among the most prevalent serotypes causing IPD in adults [36][37][38][39]. This raises the question of whether PCV13 has limited ability to reduce serotype 3 carriage (and thus provide indirect protection), limited ability to provide direct protection against this serotype in vaccinated persons, or both.…”

Predicted serotype distribution in invasive pneumococcal disease (IPD) among children less than five years prior to the introduction of the Pneumococcal Conjugate Vaccine (PCV) in Nigeria

“…Although this may indicate that PCV13 may provide better protection, empirical data has shown that PCV13 has little to no protection against serotype 3 and has similar levels of serotype replacement as PCV10. (39,40) This higher predictions in serotype coverage for PCV13 may therefore not translate to larger IPD reductions. Our predictions show that SII-PCV has similar coverage to PCV10, and we attribute this to differences in carriage prevalence and IC of the included and excluded serotypes.…”