Carriage ofStreptococcus pneumoniae3 Years after Start of Vaccination Program, the Netherlands

Abstract

To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) program, we conducted a cross-sectional observational study on nasopharyngeal carriage of Streptococcus pneumoniae 3 years after implementation of the program in the Netherlands. We compared pneumococcal serotypes in 329 prebooster 11-month-old children, 330 fully vaccinated 24-month-old children, and 324 parents with age-matched pre-PCV7 (unvaccinated) controls (ages 12 and 24 months, n = 319 and n = 321, respectively) and 296 of their parents. PCV7 serotype prevalences before and after PCV7 implementation, respectively, were 38% and 8% among 11-month-old children, 36% and 4% among 24-monthold children, and 8% and 1% among parents. Non-PCV7 serotype prevalences were 29% and 39% among 11-monthold children, 30% and 45% among 24-month-old children, and 8% and 15% among parents, respectively; serotypes 11A and 19A were most frequently isolated. PCV7 serotypes were largely replaced by non-PCV7 serotypes. Disappearance of PCV7 serotypes in parents suggests strong transmission reduction through vaccination.

The impact of a pneumococcal conjugate vaccination program on the nasopharyngeal carriage, serotype distribution and antimicrobial resistance of Streptococcus pneumoniae among healthy children in Turkey

“…Each of these studies demonstrated that the carriage of VT serotypes decreased but resulted in increased non-VT serotype carriage, particularly serotype 19A; overall NP carriage did not change. These findings were supported by a recent systematic review of clinical trials assessing SPNP carriage [8][9][10][11]. However, the number of clinical trials assessing PCV13 effectiveness against SPNP carriage was small.…”

Spectrum of Pneumococcal Serotype 11A Variants Results from Incomplete Loss of Capsule O -Acetylation

“…Following the widespread use of pneumococcal conjugate vaccines, serotype 11A has become one of the most prevalent serotypes among pneumococci isolated from the nasopharynx (16)(17)(18) and, in one U.S. multicenter study, isolated from invasive disease (19). It can be postulated that pneumococci expressing serotypes 11A and 11E have contributed equally to the increase in "serotype 11A" prevalence.…”

Decreased Carriage and Genetic Shifts in the Streptococcus pneumoniae Population After Changing the Seven-valent to the Thirteen-valent Pneumococcal Vaccine in Norway

“…Twenty-two isolates [4% (2-6)] were resistant to erythromycin. Coresistance to erythromycin, clindamycin and tetracycline was found in 18 isolates [3% (2)(3)(4)(5)(6)]. These coresistant isolates belonged to ST/serotypes ST179/19F, ST63/15A, ST344/NT and ST4310/6C.…”