Person-to-person transmission now more common source of hepatitis A in U.S. than food
An analysis of hepatitis outbreaks in 2016 to 2020, comprising 37,553 cases, found that 56% of patients reported drug use, 14% reported homelessness, 12% reported recent incarceration, and 3% reported recent international travel.
The source of hepatitis A infections in the U.S. has shifted from contaminated food to person-to-person transmission, according to a new CDC analysis of recent outbreaks.
The study looked at reports of hepatitis A outbreaks in 33 states from Aug. 1, 2016, to Dec. 31, 2020, including a total of 37,553 hepatitis A cases. Most patients were male (62%), White (81%), and ages 30 to 49 years (58%). Among cases with available information, 56% of persons reported drug use, 14% reported homelessness, 12% reported recent incarceration, and 3% reported recent international travel. Sixty-one percent of the patients were hospitalized, and 380 outbreak-associated deaths were reported (1%). Results were published by MMWR on Sept. 30.
The study authors noted that hepatitis A infections declined by about 97% in the U.S. from 1995 to 2015, thanks to the introduction and widespread pediatric use of hepatitis A vaccines, but since 2016, outbreaks have been reported in 37 states, involving about 44,650 cases. “The outbreaks described in this report are unprecedented in the hepatitis A vaccine era,” they wrote.
The current report confirms evidence from 2017 showing that most hepatitis A infections occurred among people with drug use or those experiencing homelessness, which led the Advisory Committee on Immunization Practices in 2019 to recommend vaccination of persons experiencing homelessness and reinforce existing vaccination recommendations for persons who use drugs. “Improving services for these populations, including access to substance use treatment and sanitation, are important considerations in mitigating [hepatitis A virus] transmission,” added the study authors.
They called on public health officials to implement “nontraditional vaccination strategies to reach disproportionately affected populations, along with improved universal and catch-up childhood vaccination” to respond to existing outbreaks and prevent future ones.
Limitations of the study include that risk factor data were self-reported, that hepatitis A surveillance in the United States is passive, and that a substantial proportion of data was missing.