Effectiveness of different vaccine schedules for heptavalent and 13-valent conjugate vaccines against pneumococcal disease in the Community of Madrid

Abstract Introduction The heptavalent pneumococcal conjugate vaccine (PCV-7) was added to the childhood routine vaccination program in the Community of Madrid in November of 2006 with 3 + 1 recommended doses and a catch-up for those under 2 years old. In June 2010, PCV-7 was replaced by 13-valent vaccine (PCV-13) with 2 + 1 recommended doses. In July of 2012, the PCV-13 was removed from the funded program and reintroduced again (2 + 1 recommended doses) in December 2014. In between, children were vaccinated privately with 3 + 1 recommended doses of PCV-13. The aim of this study was to evaluate the effectiveness of each vaccination schedule used in the Community of Madrid. Methods We included all cases of invasive pneumococcal disease (IPD) reported between 2007 and 2015 to the Notifiable Diseases Surveillance System. Vaccination information was obtained from the Immunization Registry. Vaccine effectiveness (VE) was estimated using the indirect cohort design for cases with serotype information. Results A total 779 cases were included in the study. Among them 47.6% of the cases were primo-vaccinated with booster, 20% primo-vaccinated, 15.9% incompletely primo-vaccinated and 16.5% not vaccinated. The VE for ≥1 doses of any PCV was 82% (CI 95%: 67.8–89.9%): 91.9% (CI 95%: 76.5–97.2%) for PCV-7 and 77.2% (48.6–89.9%) for PCV-13. VE in those receiving the full 2 + 1 or 3 + 1 schedules was 100% for both vaccines. Conclusions A high number of vaccine failures were reported in children before they had the opportunity to receive the booster dose, especially due to PCV-13-non-PCV-7 serotypes. VE was higher for PCV-7 compared to PCV-13, except for those that received the complete schedule with booster that achieved 100% of VE, which shows the relevance of the vaccines and complying with all doses scheduled.