Outbreaks of hepatitis A among illicit drug users, Oklahoma, 1984-87.

Transmission of hepatitis A has been described in many settings, although few outbreaks have been reported among illicit drug users. We report six unrelated outbreaks of hepatitis A among users of marijuana and intravenously administered methamphetamine. Although the exact mode of transmission could not be determined, practices associated with illicit drug use may have facilitated transmission of hepatitis A. These outbreaks and other recent information indicate that illicit drug users may be at increased risk of acquiring hepatitis A infection.