Recent large outbreaks of hepatitis A virus (HAV) among individuals experiencing homelessness and people who inject drugs (PWID) have contributed to a nearly fourfold rise in the new infection rate between the periods of 2013 to 2015 and 2016 to 2018.

Publishing their findings in the Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention (CDC) researchers analyzed data about hepatitis A diagnoses from the National Notifiable Diseases Surveillance System. Between 2016 and 2018, 15,000 cases of hepatitis A were reported to this system, representing a 3.94-fold increase compared with the number of cases reported during 2013 to 2015.

Between 1996 and 2011 and 2013 to 2015, hepatitis A infections declined by 95%.

Thanks to the implementation of routine hepatitis A vaccination among children, the epidemic of the virus is no longer associated with asymptomatic pediatric cases. Instead, it is largely driven by outbreaks among major risk groups of unvaccinated individuals, including those experiencing homelessness, PWID and men who have sex with men. There are also smaller numbers of cases among people who consume contaminated food from countries where the virus is endemic.

Nine jurisdictions experienced a greater than sixfold increase in their hepatitis A rate between 2013 to 2015 and 2016 to 2018, including West Virginia, Tennessee, Kentucky, Ohio, Indiana, Missouri, Arkansas, Utah and Washington, DC.

The 2019 national immunization guidelines newly included homelessness as an indication for the hepatitis A vaccine. Other indications include injection drug use, chronic liver disease, being  a man who has sex with men, and travel to countries where the virus is endemic.

To read the MedPage Today article, click here.

To read the CDC report, click here.