In the U.S., hepatitis A outbreaks are repeatedly affecting people experiencing homelessness or who use drugs. A 2017-19 Kentucky outbreak primarily among these groups resulted in 501 cases, six deaths. Vaccination efforts likely averted 30 hospitalizations and $490K in costs, but UC San Diego and Oxford researchers say more could have been saved if initiated earlier and faster. They determined herd immunity in these populations requires 77 percent vaccinated, underscoring need for outreach.
