Number of reported cases* and estimated infections of hepatitis A — United States, 2015–2022

Number of reported cases* and estimated infectionsof hepatitis A — United States, 2015–2022 

Source: CDC, National Notifiable Diseases Surveillance System.
* Reported confirmed cases. For the case definition, see Acute Hepatitis A.
† The number of estimated viral hepatitis infections was determined by multiplying the number of reported cases that met the classification criteria for a confirmed case by a factor that adjusted for underascertainment and underreporting. The 95% bootstrap confidence intervals for the estimated number of infections are displayed in the Appendix.

The number of reported cases of hepatitis A began to increase during 2016 when two foodborne outbreaks and multiple outbreaks associated with person-to-person transmission, primarily among persons who use drugs and those experiencing homelessness, were first reported. Outbreaks associated with person-to-person transmission have since been reported in multiple states,1 resulting in substantial increases in hepatitis A peaking at 18,846 reported cases in 2019, then decreasing in 2020 and 2021. During 2022, the number of reported cases was 2,265, which corresponds to 4,500 estimated infections after adjusting for case underascertainment and underreporting.2 The number of reported cases during 2022 corresponds to a 60% decrease from 2021 but remains 1.6 times the number reported during 2015, before the hepatitis A outbreaks associated with person-to-person transmission were first reported. During 2022, 14 out of 23 states with ongoing outbreaks declared an end to their outbreaks. Disruptions to healthcare access and health department surveillance capacity during the COVID-19 pandemic may have affected the ability to detect, investigate, and report all hepatitis A cases during 2020–2022.


  1. Centers for Disease Control and Prevention (CDC). Person-to-person outbreaks of hepatitis A across the United States. Atlanta, GA: US Department of Health and Human Services, CDC 2023.
  2. Klevens RM, Liu, S, Roberts H, et al. Estimating acute viral hepatitis infections from nationally reported cases. Am J Public Health 2014;104:482. PMC3953761.