Municipality-level measles, mumps, and rubella (MMR) vaccine coverage and deprivation in Brazil: A nationwide ecological study, 2006 to 2020.

To better understand the declining rates of routine childhood vaccination in Brazil, we investigated the association between measles, mumps, and rubella (MMR) first dose vaccine coverage and deprivation at the municipality level. Using routinely collected data from 5565 Brazilian municipalities from 2006 to 2020, we investigated the association between municipality-level MMR vaccine first dose coverage (i.e., as a continuous variable and as a percentage of municipalities attaining the 95% target coverage) in relation to quintiles of municipality-level deprivation, measured by the Brazilian Deprivation Index (Índice Brasileiro de Privação, IBP), and geographic regions. From 2006 to 2020, the mean municipality-level MMR vaccine coverage declined across all deprivation quintiles and regions of Brazil, by an average of 1.2% per year. The most deprived quintile of municipalities had higher coverage on average, but also the steepest declines in coverage (i.e., an annual decline of 1.64% versus 0.61% in the least deprived quintile) in the period of 2006-2020, and the largest drop in coverage at the beginning of the COVID-19 pandemic (2019-2020). Across all deprivation quintiles and regions (except for the Southeast region), less than 50% of municipalities in Brazil met the 95% MMR coverage target in 2020.The decrease in MMR first dose vaccine coverage in Brazil is widespread, but steeper declines have been observed in the most deprived municipalities. To promote vaccine equity and prevent future outbreaks, further research is urgently needed to understand the causal mechanisms underlying the observed associations between municipality-level MMR vaccine coverage and deprivation.

Effect of maternal Tdap on infant antibody response to a primary vaccination series with whole cell pertussis vaccine in São Paulo, Brazil.

BACKGROUND: Maternal Tetanus, diphtheria, and acellular pertussis (Tdap) vaccination provides antibody transfer to newborn infants and may affect their antibody response to the primary vaccination series. This study aimed to assess the effect of Tdap vaccination during pregnancy on infant antibody response to the whole cell pertussis (DTwP) primary series. METHODS: Plasma from 318 pregnant women (243 Tdap-vaccinated and 75 unvaccinated) and their infants (cord blood) was collected at delivery; infant blood was again collected at 2 and 7 months, before and after their primary DTwP series. Anti-pertussis toxin (PT), pertactin (PRN), filamentous hemagglutinin (FHA), fimbriae 2/3 (FIM) and adenylate cyclase toxin (ACT) IgG antibodies were quantified by a microsphere-based multiplex antibody capture assay and anti-PT neutralizing antibodies by the Real Time Cell analysis system. RESULTS: Infant geometric mean concentrations (GMCs) of IgG anti-Tdap antigens were significantly higher (p < 0.001) among the Tdap-vaccinated (PT: 57.22 IU/mL; PRN: 464.86 IU/mL; FHA: 424.0 IU/mL), versus the unvaccinated group (4 IU/mL, 15.43 IU/mL, 31.99 IU/mL, respectively) at delivery. Anti-FIM and ACT GMCs were similar between the two groups. At 2 months of age, anti-PT, PRN, and FHA GMCs remained higher (p < 0.001) in the Tdap-vaccinated group (12.64 IU/mL; 108.76 IU/mL; 87.41 IU/mL, respectively) than the unvaccinated group (1.02 IU/mL; 4.46 IU/mL; 6.89 IU/mL). However, at 7 months, after receiving the third DTwP dose, the anti-PT GMC was higher (p = 0.016) in the unvaccinated group (7.91 IU/mL) compared to the vaccinated group (2.27 IU/mL), but without differences for anti-PRN, FHA, FIM and ACT GMCs. CONCLUSION: Elevated antibody levels suggest that maternal Tdap vaccination might protect infants until 2 months of age. Reduced anti-PT levels at 7 months indicate potential blunting of immune response in infants. Surveillance would help determine if blunting alters vaccine immunity and impacts pertussis prevention in infants.

The effectiveness of maternal pertussis vaccination in protecting newborn infants in Brazil: A case-control study.

INTRODUCTION: In 2014, the Brazilian Ministry of Health (MoH) recommended Tdap to pregnant women in response to a significant increase in the incidence of pertussis among infants. The present study assessed the effectiveness of maternal immunization in preventing pertussis in infants. METHODS: An unmatched case-control study was undertaken in São Paulo State, Brazil from February 2015 to July 2016. Cases were infants aged <8 weeks at onset of pertussis reported to the Surveillance System and confirmed by real-time polymerase chain reaction or culture. Four to six healthy infants were selected as controls per case from birth certificates in the Information System on Live Births database. General characteristics and mother's vaccination status were compared between cases and controls. The vaccine effectiveness (VE) was calculated as 1 - odds ratio (OR). For the adjusted VE, the OR was calculated using logistic regression analysis. RESULTS: Forty-two cases and 248 controls were enrolled in the study. Mothers of 8 cases (19.1%) and 143 controls (57.4%) were vaccinated during pregnancy, resulting in an unadjusted VE of 82.6% (95% confidence interval [CI], 60.8-92.3%). The VE was unchanged after adjusting for maternal age and monthly household income. CONCLUSION: Maternal pertussis vaccination during pregnancy was effective in protecting infants aged <8 weeks from pertussis.