Local and state public health officials continue to investigate a large hepatitis A outbreak in southeastern Michigan. Recently, there has been a concerning increase in confirmed hepatitis A cases among men who have sex with men (MSM). As part of the ongoing investigation, residents are encouraged to be aware of the associated risk factors, and the importance of handwashing and vaccination to prevent hepatitis A infection.

Hepatitis A Vaccine Image/National Institute of Diabetes and Digestive and Kidney Diseases
Hepatitis A Vaccine
Image/National Institute of Diabetes and Digestive and Kidney Diseases

Since August 1, 2016, there have been 457 confirmed cases of hepatitis A in the City of Detroit, Ingham, Lapeer, Livingston, Macomb, Monroe, Oakland, Sanilac, St. Clair, Washtenaw, and Wayne Counties reported to the Michigan Department of Health and Human Services (MDHHS).

From August 1, 2016 to October 1, 2017, there were 10 hepatitis A cases among MSM. Since October 1, 2017, 11 additional hepatitis A cases identifying as MSM have been referred over four weeks. Among the recent MSM hepatitis A cases, the hospitalization rate is higher (95.2 percent) and the median age is younger (38 years) compared to the larger outbreak population. Substance abuse was reported by almost half of the cases, a risk factor associated with the larger outbreak.

In terms of the outbreak as a whole, primary cases range in age from 20 to 87 years with median age of 42 years. The majority are male (63 percent) and have been hospitalized (85.6 percent). Eighteen deaths are associated with the outbreak. Forty-eight percent of cases reported illicit drug use, 27.5 percent were co-infected with hepatitis C, and 3 percent were co-infected with hepatitis B. Six percent report recent incarceration, and 7.7 percent of men reported having sex with men. Transmission has primarily been person-to-person with no single source identified.

The hepatitis A vaccination is recommended for MSM by the national Advisory Committee on Immunization Practices. Despite this guidance, hepatitis A vaccination coverage among MSM in the United States remains low leaving many adult men unprotected. There are currently multiple hepatitis A outbreaks among MSM in the United States and Western European countries.

MDHHS urges all men who have sex with men to get vaccinated against hepatitis A to protect themselves and their close contacts. Hepatitis A vaccine is available at local pharmacies, through healthcare providers, or at local health departments. One dose of hepatitis A vaccine is at least 90 percent effective at preventing infection if given before any exposure to hepatitis A. The vaccine is inactivated and safe for all individuals including those with liver disease or weakened immune systems.