Los Angeles County public health officials have declared hepatitis A outbreak. This is a highly contagious liver infection driven by a virus that can rarely cause severe illness.
The condition, which is identified in less than 50 cases in LA County each year, infected at least 138 people in 2024 and remains a very high case so far in 2025.
Here's what you need to know.
How is hepatitis A contagious?
Hepatitis A virus spreads through the so-called oral fetal pathway. That is, it is consumed through food and drinks contaminated with microscopic stools from infected people. Also, even if you are not showing symptoms, it can spread through close contact with someone carrying the virus.
Inappropriate people are often at a higher risk of contracting hepatitis A due to limited access to proper toilets and hand washing facilities. The virus is more common among travelers, in poorly hygienic places, men having sex with men, and people using drugs.
However, officials say many of the recent cases have occurred in people without these risk factors. They don't know why yet, but Dr. Timothy Brewer, an infectious disease physician and epidemiologist at UCLA, said he led them to worry about two things: food pollution and community circulation.
“If you're practicing good hygiene in a community with access to drinking water, you shouldn't really see a lot of this,” he said. “Something is going on, but we don't know exactly what it is.”
What are the symptoms of hepatitis A infection?
The first signs of infection appear to be fever, fatigue, nausea, loss of appetite, followed by vomiting and diarrhea. Over time, infected people may experience yellow skin and eyes, dark urine, and pale stool.
One of the challenges to stop the development of hepatitis A is that contact tracing can be nearly impossible. The infection can be incubated for up to 7 weeks before symptoms appear, and those carrying the virus can spread for up to 2 weeks before they feel sick.
Additionally, a significant proportion of infected people do not experience significant symptoms, said Dr. Edward Jones Lopez, an infectious disease expert at Keck Medicine at the University of Southern California, so they don't visit doctors, perform blood tests and report cases.
Severe symptoms are most common in elderly people, people with chronic liver conditions, and people with weakened immune systems or HIV. In rare cases, hepatitis A infection is fatal. At least seven people died in the outbreak. While that may seem like an unusually high mortality rate, officials believe that far more people are infected than official figures show. Most are probably asymptomatic or have mild symptoms that are misidentified.
How is hepatitis A treated?
There are no specific antiviral drugs for hepatitis A. The infection is usually dismantled on its own within a few weeks, and most people are not facing permanent liver damage. However, for some people, hospitalization may be required.
In rare cases, infections can lead to acute liver failure called fulminant hepatitis, which may require transplantation, said Dr. Jones Lopez. “It can progress very quickly. It's a very serious illness.”
If you think you may be infected, visit your doctor, drink plenty of liquids and get plenty of rest.
How can I avoid that?
The best way to prevent hepatitis A is through vaccination. The regimen – two vaccines separated for at least six months – protect lives. Although it has been given to children on a daily basis for the past 20 years, many adults over the age of 25 do not get shots unless they are in a high-risk group.
“Anywhere, wherever you are infected, it's an infection everywhere,” says Dr. Anne Limoyne, a professor of epidemiology at UCLA.
If you have not been vaccinated but know you are exposed to someone carrying the virus, a rapid vaccination can prevent you from getting infected. Experts say some people with an exposed immune system may also benefit from receiving immunoglobulins. And good hygiene is a wise safeguard for everyone. Wash your hands with soap and water, especially after using the toilet, before preparing food.
