Figure 1.1. Number of reported hepatitis A virus infection cases and estimated infections* — United States, 2012–2019

Figure 1.1. Number of reported hepatitis A virus infection cases and estimated infections* — United States, 2012–2019

Source: CDC, National Notifiable Diseases Surveillance System.
*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.

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During 2012–2015, the number of reported cases of hepatitis A ranged from approximately 1,200 to 1,800 cases yearly. The number of reported cases of hepatitis A began to increase during 2016, when 2 foodborne outbreaks were reported, and person-to-person outbreaks of hepatitis A, primarily among persons who use drugs and those experiencing homelessness, were first reported. Since then, person-to-person outbreaks have been reported in multiple states, resulting in substantial increases in hepatitis A. During 2019, the number of reported cases was 18,846, which corresponds to 37,700 estimated infections after adjusting for case underascertainment and underreporting. The number of reported cases during 2019 corresponds to a 51% increase from 2018 and is >13 times the number reported during 2015, before the person-to-person outbreaks were first reported.

Source: 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. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3953761/pdf/AJPH.2013.301601.pdf