There is a hepatitis A outbreak in LA County. Why you need to know

At least seven people have died during this outbreak, according to local media.

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(CNN) — Los Angeles County is facing a community-wide outbreak of the contagious virus hepatitis A, citing a sustained increase in clinical cases and elevated virus levels detected in wastewater testing.

The county reported on May 5 that there have been 29 confirmed cases of hepatitis A this year. That number is out of a total 165 documented cases since the start of 2024, which is three times the total number of cases reported in 2023. At least seven people have died during this outbreak, according to local media.

What is hepatitis A? What symptoms does it cause? How is it diagnosed and treated? Who are the individuals most vulnerable to severe outcomes? Who should be vaccinated against the disease? And what other steps can people take to reduce their chance of contracting it?

To guide us through these questions, I spoke with CNN wellness expert Dr. Leana Wen. She is an emergency physician and clinical associate professor at the George Washington University. Wen previously served as Baltimore’s health commissioner.

CNN: What is hepatitis A?

Dr. Leana Wen: Hepatitis A is a liver disease caused by the hepatitis A virus, which is highly contagious. Most people who develop the disease will recover completely, without lasting liver damage. However, some people can become very sick — they can develop liver failure, require intensive care and die.

CNN: How is hepatitis A transmitted?

Wen: The hepatitis A virus is transmitted primarily through the fecal-oral route, meaning that someone gets it by ingesting food or water that has been contaminated with the virus from an infected person.

This type of transmission could occur with individuals living in close quarters — for instance, when an infected person prepares food for family members or when someone is caring for an infected person and doesn’t wash their hands fully before eating. Waterborne outbreaks also can happen when there is sewage contamination. Another pathway for virus transmission is through sexual contact, such as oral-anal intercourse.

CNN: What symptoms does it cause?

Wen: Symptoms of hepatitis A can include fatigue, fever, joint pain, nausea, diarrhea, dark urine or clay-colored stools and jaundice, which is yellowing of the skin or eyes. The symptoms typically resolve within two months, though some people can feel ill for as long as six months.

It’s important to note that some people with hepatitis A could be asymptomatic, which means that they could be infected without having any symptoms and pass the virus unknowingly to others. The possibility of asymptomatic transmission, along with the very long incubation period for hepatitis — people are infected for usually 14 to 28 days before they show symptoms — make controlling outbreaks challenging.

CNN: How is hepatitis A diagnosed and treated?

Wen: The diagnosis requires a blood test, which looks for the presence of a particular antibody (hepatitis A virus IGM antibody) that identifies acute infection with the hepatitis A virus. This blood test is positive two weeks before the onset of symptoms and lasts about six months after.

There is no specific treatment, antiviral or otherwise, for hepatitis A. The therapies are all supportive in nature, which means doctors will try to ease your symptoms. Individuals who are dehydrated may receive intravenous hydration. People experiencing fatigue are told to rest. The majority of cases are mild and people recovery fully. Severe cases may require hospitalization. If someone experiences the rare complication of liver failure, they may require a liver transplant.

CNN: Which people are more likely to have severe illness?

Wen: The people most likely to experience severe outcomes include older individuals and those with significant underlying medical conditions, such as chronic liver disease and immunocompromise.

CNN: Who is most likely to contract hepatitis A?

Wen: A key risk factor is visiting parts of the world where hepatitis A is common, such as Central and South Africa, eastern Europe and parts of Asia. People who may be at higher risk include those experiencing homelessness, men who have sex with men and people who use illegal drugs.

In Los Angeles County, officials have said that most of the recent cases involve individuals who do not have these specific risk factors. They don’t know what exactly is driving the outbreak; investigations are underway.

CNN: Is there a hepatitis A vaccine? Who should be vaccinated?

Wen: There are two types of hepatitis A vaccines available. One of them is a two-dose vaccine against hepatitis A. The other is a three-dose vaccine that protects against both hepatitis A and hepatitis B. The combination vaccine is only available for people 18 and older.

The US Centers for Disease Control and Prevention recommends the two-dose hepatitis A vaccine to all children ages 12 months to 23 months. The two shots are typically administered over the course of six months. The CDC recommends that children who did not receive the vaccine before 23 months still receive the two doses. No additional booster doses are recommended after initial vaccination series is completed.

Adults at increased risk of contracting hepatitis A virus as well as those at increased risk for severe disease if they were to contract the virus are also recommended to receive the vaccine. Vaccination is also recommended to people who are unvaccinated and who have been exposed to the hepatitis A virus in the preceding two weeks.

In outbreak settings, such as in Los Angeles County, unvaccinated people at higher risk for contracting the virus or for developing severe disease are recommended to receive the vaccine.

CNN: I don’t live in Los Angeles. Should I still get vaccinated?

Wen: Everyone should follow the CDC’s guidance on hepatitis A vaccinations. All children should be vaccinated as part of their routine childhood immunizations. Adults who are either at increased risk of contracting hepatitis A or at increased risk of severe disease from it should get the vaccine.

CNN: What are the side effects of the vaccine?

Wen: The hepatitis A vaccine is a safe and effective vaccine. Side effects include pain and tenderness at the site of the injection, low-grade fever, loss of appetite and nausea. They are generally mild and go away in the first two days following vaccination.

CNN: What other steps can people take to reduce their chance of contracting hepatitis A?

Wen: The best way to prevent infection is through vaccination. Individuals living in outbreak areas and others who are at high risk who have not been vaccinated should be sure to do so. Good hand hygiene can also reduce the spread of hepatitis A.

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