BCG revaccination does not protect against leprosy in the Brazilian Amazon: a cluster randomised trial.

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TitleBCG revaccination does not protect against leprosy in the Brazilian Amazon: a cluster randomised trial.
Publication TypeJournal Article
AuthorsCunha SS, Alexander N, Barreto ML, Pereira ES, Dourado I, de Maroja MF, Ichihara Y, Brito S, Pereira S, Rodrigues LC
Abbrev. JournalPLoS Negl Trop Dis
JournalPLoS neglected tropical diseases
Year of Publication2008
Publication Languageeng
KeywordsAdolescent, BCG Vaccine, Brazil, Child, Female, Humans, Incidence, Leprosy, Male, Vaccination

BACKGROUND: Although BCG has been found to impart protection against leprosy in many populations, the utility of repeat or booster BCG vaccinations is still unclear. When a policy of giving a second BCG dose to school children in Brazil was introduced, a trial was conducted to assess its impact against tuberculosis, and a leprosy component was then undertaken in parallel.

OBJECTIVE: to estimate the protection against leprosy imparted by a second dose of BCG given to schoolchildren.

METHODS AND FINDINGS: This is a cluster randomised community trial, with 6 years and 8 months of follow-up.

STUDY SITE: City of Manaus, Amazon region, a leprosy-endemic area in Brazil.

PARTICIPANTS: 99,770 school children with neonatal BCG (aged 7-14 years at baseline), of whom 42,662 were in the intervention arm (revaccination).

INTERVENTION: BCG given by intradermal injection.

MAIN OUTCOME: Leprosy (all clinical forms).

RESULTS: The incidence rate ratio of leprosy in the intervention over the control arm within the follow-up, in schoolchildren with neonatal BCG, controlled for potential confounders and adjusted for clustering, was 0.99 (95% confidence interval: 0.68 to 1.45).

CONCLUSIONS/SIGNIFICANCE: There was no evidence of protection conferred by the second dose of BCG vaccination in school children against leprosy during the trial follow-up. These results point to a need to consider the effectiveness of the current policy of BCG vaccination of contacts of leprosy cases in Brazilian Amazon region.

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PubMed Central IDPMC2238709
Grant ListG0700837 / / Medical Research Council / United Kingdom