Public health officials in Los Angeles County have officially declared an outbreak of hepatitis A, a highly contagious liver infection caused by a virus that can lead to severe illness in rare cases. Typically, the county sees fewer than 50 cases of hepatitis A each year; however, in 2024 alone, at least 138 individuals were infected. Alarmingly, the number of cases has remained unusually high in early 2025. Officials warn that the actual figures may be even higher, as levels of the virus detected in local wastewater indicate an undercount of the current outbreak.
The hepatitis A virus is primarily transmitted through the oral-fecal route. This means that individuals can become infected by consuming food or drinks contaminated with microscopic traces of stool from an infected person. Close contact with someone who has the virus, even if they are asymptomatic, can also facilitate its spread.
Individuals experiencing homelessness are particularly vulnerable to contracting hepatitis A due to their limited access to adequate sanitation facilities, such as toilets and hand-washing stations. The virus is also prevalent among specific groups, including travelers to regions with poor sanitation, men who have sex with men, and individuals who use drugs. However, health officials have noted that many recent cases have emerged among individuals lacking these typical risk factors, raising concerns.
Dr. Timothy Brewer, an infectious disease physician and epidemiologist at U.C.L.A., expressed his worries regarding the outbreak. He highlighted two critical concerns: the potential for food contamination and the possibility of the virus circulating within the community. “If you’re practicing good hygiene in a community that has access to potable water, you really should not be seeing a lot of this,” Dr. Brewer stated. “Something is going on — but exactly what that something is, we don’t yet know.”
As public health officials continue to monitor the situation, they urge the community to remain vigilant and practice good hygiene to help curb the spread of hepatitis A.
