Impact of the single-dose universal mass vaccination strategy against hepatitis A in Brazil.

Universal vaccination of children against hepatitis A was introduced in 2014 in Brazil as a single-dose schedule. We analyzed the numbers of reported cases of hepatitis A virus infection (HAV) from 2010 to 2017 to evaluate the initial impact of that intervention. Data were assessed and has been freely available on the Brazilian Ministry of Health website. The HAV incidence was steady around 6000 cases per year until 2014. Between 2014 and 2016, there was a 85.5% cumulative drop, independent of gender and geographical macroregions. The fall was especially significant among toddlers (96.8%). In 2017, cases increased due to an outbreak among male adults in São Paulo. Decrease in incidence continued to occur for females and for those under 15 years of age. Data show that there was a significant decrease in HAV cases number in Brazil from 2015 after the introduction of single-dose HAV vaccine program.