Hepatitis A Infections Up Nearly 300% in Recent Years

Troy Brown, RN

May 09, 2019

Hepatitis A virus (HAV) infections have risen almost 300 percent in recent years, the US Centers for Disease Control and Prevention (CDC) reports. The rise is largely a result of widespread outbreaks among those who report drug use or homelessness.

"During 2016–2018, reports of hepatitis A infections in the United States increased by 294% compared with 2013–2015, related to outbreaks associated with contaminated food items, among men who have sex with men, and primarily, among persons who report drug use or homelessness," the researchers write.

The report, by Monique A. Foster, MD, and colleagues from the Division of Viral Hepatitis, National Center for HIV, Viral Hepatitis, STD, and TB Prevention, CDC, was published online today in Morbidity and Mortality Weekly Report.

Two foodborne outbreaks of HAV occurred in 2016, and cases among men who have sex with men have increased; however, in 16 states, the bulk of cases have resulted from widespread outbreaks among those who report using drugs or being homeless.

Rates of HAV infection fell by approximately 95% from 1996 to 2011, but they have rebounded more recently. From 2016 through 2018, approximately 15,000 infections were reported from US states and territories.

The CDC tested 4282 specimens during 2016–2018. Of those, 3877 (91%) had detectable HAV RNA; of those, 565 (15%) were of genotype IA, 3255 (85%) were of genotype IB, and 57 (<1%) were of genotype IIIA.

During 2013–2015, of 197 (87%) specimens with detectable HAV RNA, 76 (38.57%) tested positive for genotype IA, 121 (61.42%) tested positive for IB, and none tested positive for genotype IIIA.

"Historically, genotype IA has been the most common genotype circulating in North and South America. During 2013–2018, HAV genotype IB predominated in the United States. Increasing numbers of genotype IIIA were seen, a genotype that is considered rare in the United States," the authors write.

Case counts fell in 18 states but rose by approximately 500% in nine states and Washington, DC, during 2016–2018 compared with 2013–2015.

Whereas in the past, outbreaks of HAV infection were primarily linked to asymptomatic children, the widespread universal vaccination of children has shifted the spread of HAV to adults, according to the authors. They say that bringing HAV infection rates back down and keeping them down can best be accomplished by achieving a high level of population immunity through vaccination.

"There is no universal vaccination recommendation for adults in the United States; however, ACIP [Advisory Committee on Immunization Practices] does recommend vaccination for adults who plan travel to HAV-endemic countries, MSM [men who have sex with men], persons who use drugs, persons with chronic liver disease, and recently, persons experiencing homelessness," they conclude.

The authors have disclosed no relevant financial relationships.

Morb Mortal Wkly Rep. Published online May 9, 2019. Full text

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