Vaccination Coverage and Compliance with Three Recommended Schedules of 10-Valent Pneumococcal Conjugate Vaccine during the First Year of Its Introduction in Brazil: A Cross-Sectional Study.

Abstract

Pneumococcal 10-valent conjugate vaccine (PCV10) was introduced to Brazil's National Immunization Program (NIP) in 2010. During the first year of vaccine introduction three schedules were used to deal with age at initiation of PCV for catch-up purposes: 3 primary doses + 1 booster (for children aged ≤6 months), a catch-up schedule of 2 doses + 1 booster (7-11 months), and a catch-up schedule of a single dose (12-15 months). The purpose of this study was to assess the magnitude and associated risk factors for under-vaccination or lack of on time vaccination six to eight months after PCV10 introduction. A household survey was conducted in the municipality of Goiania with 1,237 children, who were retroactively classified into one of three age groups, as a factor of the child's age relatively to 30 days after PCV10 introduction. Socioeconomic characteristics and vaccination dates were obtained during home interviews. Vaccination coverage was defined as the percentage of children who completed the recommended number of doses. Compliance with recommended schedules was defined as the percentage of children who received all valid doses at the NIP recommended time interval. Adjusted prevalence ratios (PR) of variables independently associated with coverage and compliance were estimated by log binomial regression. Coverage of DTP-Hib was used for comparison purposes. Overall, vaccination coverage was 54.6% (95% CI 52.1-57.7%), lower than DTP-Hib coverage (93.0%; 95% CI 91.5-94.3%). Compliance with recommended schedules was 16.8% (95% CI: 14.7-18.6%). Children 7-11 months old had lower coverage (40.7%) and compliance (6.3%) compared to children aged 12-15 months (coverage: 88.8%; compliance: 35.6%) and ≤6 months old (coverage: 54%; compliance: 18.8%). Having private health insurance was associated with higher PCV10 coverage (PR=1.25; 95% CI: 1.06-1.47, p=0.007), and compliance (PR=1.09; 95% CI: 1.02-1.16, p=0.015). Although PCV10 coverage rapidly increased shortly after vaccination introduction, it was not matched by compliance with recommended schedules. Public initiatives should target compliance of PCV10 because of the burden of pneumococcal diseases on childhood morbidity and mortality.