The majority of recent studies from India conducted in urban poor settings (table 1), while providing estimates of immunisation coverage, do not include hepatitis B vaccine coverage in their definitions (with the exception of the two surveys from Delhi).12, 13 Further, most of these studies were small (median sample size of 380 participants) and did not look at determinants of complete immunisation using multivariable models. The gene discussed is PPIB; the disease is hepatitis A virus infection.