RESUMO
BACKGROUND: The Bacillus Calmette-Guérin (BCG) vaccine is recommended at birth in Guinea-Bissau but often given with delay. Delays are not evident in routine coverage estimates since coverage is measured by 12 months of age. Studies show that BCG protects against other infections than tuberculosis and lowers neonatal mortality. Hence, the timing of BCG is important since the children should benefit from these non-specific effects as early as possible. METHODS: Using data from a nationally representative health and demographic surveillance system in Guinea-Bissau, we assessed BCG coverage at birth (within the first 3 days of life), 1 month, and 12 months for children born in 2013-19. We measured the proportion of children who had a documented health system contact within the first 3 days of life, thus an opportunity for BCG at birth, and whether the opportunities were utilized. In binomial regression models, we investigated factors associated with missed opportunities for vaccination. RESULTS: Among the 22,178 children only 19 % were vaccinated at birth. By 1 month and 12 months, BCG coverages were 64 % and 93 %. The timeliness of BCG improved over time, with coverage at birth increasing from 16 % in 2013 to 25 % in 2019 and 1-month coverage from 63 % in 2013 to 75 % in 2019. If all vaccination opportunities had been utilized, the BCG coverage at birth could have reached 45 % (in the 1-month cohort) instead of the actual coverage of 19 %, as only 40 % of the vaccination opportunities were utilized. Region of residence was associated with having a missed opportunity for vaccination. CONCLUSION: The high coverage estimates at 12 months falsely imply that the vaccine is being administered according to the recommended schedule. Our findings suggest that early coverage could be markedly improved by ensuring that children are vaccinated at their first contact with the health system.
RESUMO
INTRODUCTION: Increasing evidence suggests that the BCG vaccine has non-specific effects, altering the susceptibility to non-tuberculous infections. Thus, early BCG vaccination may reduce mortality. BCG is recommended at birth but is often delayed. Vaccination opportunities are missed due to multidose vials not being opened for a few children. We will assess the effect of making BCG available at the first health-facility contact on early infant mortality and morbidity in a rural setting in Guinea-Bissau. METHODS AND ANALYSIS: In a cluster-randomised crossover trial, we randomise 23 health centres to two different treatment groups. In half of the health centres, BCG is provided as per current practice; in the remaining health centres, we make BCG available everyday to allow opening a vial of BCG if there is just one eligible child present. The randomisation of centres will be crossed over after 12 months and enrolment will continue for another 12 months.We will use logistic regression models with adjustment for village to assess the effect of making BCG available at the first health-facility contact. The main outcome is non-accidental mortality between day 1 and day 42 after birth. We will adjust for sex, health centre, period (before/after crossover) and level of surveillance (level 1 or level 2). Further analyses include assessment of the effect on hospital admission and a cost-effectiveness evaluation. ETHICS AND DISSEMINATION: If BCG vaccination reduces early infant mortality, missed opportunities and delays of vaccinations expose infants in several low-income countries to unnecessary excess mortality risk. The present trial will provide information on the effect of implementing a feasible intervention, where all children receive BCG at their first health-facility contact. Consent is obtained from all pregnant women registered as part of the trial. The results of the study will be published and communicated to the National Institute of Public Health in Guinea-Bissau. TRIAL REGISTRATION NUMBER: NCT04658680; Clinicaltrials.gov.
