Hepatitis A virus (HAV) genotype IA was most common among strains tested in US outbreak investigations and surveillance during 1996-2015. However, HAV genotype IB gained prominence during 2016-2019 person-to-person multistate outbreaks. Detection of previously uncommon strains highlights the changing molecular epidemiology of HAV infection in the United States.
Keywords: Hepatitis A virus; United States; food safety; genotype; molecular surveillance; outbreaks; sexually transmitted infections; surveillance; technical assistance; viruses.