Hepatitis B vaccination timing: results from demographic health surveys in 47 countries

Chronic hepatitis B virus (HBV) infection continues to make a substantial contribution to the global burden of disease. The risk of developing chronic HBV is inversely related to the age at acquisition of infection. Immunization is the most effective measure to prevent the transmission of HBV. In 2014, the World Health Organization (WHO) reaffirmed the need for hepatitis B vaccines to become an integral part of national immunization schedules. WHO recommends a birth dose within 24 hours of birth to prevent perinatal and early horizontal HBV transmission.8 The birth dose should be followed by 2 or 3 doses of monovalent or multivalent hepatitis B vaccines. Vaccination coverage estimates from WHO and the United Nations Children’s Fund (UNICEF) capture the proportion of vaccinated children in specific age groups. However, these estimates provide little insight into the extent to which vaccinations are administered on time and they tend to understate the susceptibility to HBV infection in a population.9–11 In