Though having slowed in recent months, several recent widespread hepatitis A outbreaks have affected states across the country, including long-term outbreaks in California and Michigan, and more recently Utah, Colorado and Kentucky. These cases have occurred primarily among persons who are experiencing homelessness, persons who use injection and non-injection drugs, and their close direct contacts. Homelessness is a particularly significant risk factor, as the lack of access to restrooms and sinks results in poor hygiene and unsanitary conditions. People experiencing homelessness may also have underlying health conditions or drug addictions that might make their infections more severe.

In southeast Michigan, 736 cases have been identified with over 81% of those cases having been hospitalized, and is the largest hepatitis A outbreak in this country since the hepatitis A vaccine became available in 1996. Twenty-four people have died. Transmission appears to be largely occurring among people using injection drugs. Intravenous drug use itself is not a risk for hepatitis A transmission; rather, the risk comes from their often unsanitary environments. Those with a history of injection and non-injection drug use, homelessness or transient housing, and incarceration are thought to be at greatest risk in this outbreak setting.

The outbreak in southern California has affected 689 people in three different counties. More than 65% of people have been hospitalized and 21 people have died. The southern California outbreak is largely affecting people experiencing homelessness and their close contacts.

More recently, outbreaks have been reported in Utah, Colorado, and Kentucky. In Salt Lake City and Utah counties, 176 people, largely homeless, have been diagnosed since May. In Kentucky, 91 cases have been identified since August, also in homeless and/or drug-using individuals. Both outbreaks in Utah and Kentucky are directly related to the outbreak in southern California and are ongoing. An outbreak in Colorado, also linked to California’s outbreak, has ended with 63 cases, affecting such high-risk groups such as men who have sex with men, people experiencing homelessness and people using illegal drugs.

The hepatitis A vaccine is routinely administered to children, but most adults are not vaccinated. Two doses of the vaccine must be given six months apart. While anyone who wishes to receive the vaccine can, it is strongly recommended for:

• All children,
• Men who have sex with men,
• People who use drugs,
• People with chronic liver disease,
• People who are homeless,
• Travelers to certain countries,
• Family members and caregivers of adoptees from certain countries, and
• People who are treated with blood-clotting factor concentrates.