Particle.news

Download on the App Store

Los Angeles County Faces Largest Hepatitis A Outbreak in Over a Decade

Health officials report sustained case increases into 2025, with expanded vaccination and hygiene efforts underway.

File photo: a microscope image made available by the U.S. Centers for Disease Control and Prevention shows a group of hepatitis virions, strain unknown.
Image
Hepatitis A virus (picornavirus). The HAV. almost always causes mild hepatitis. View produced from a transmission electron microscopy image. Viral diameter approximately: 30 nm. (Photo by: CAVALLINI JAMES/BSIP/Universal Images Group via Getty Images)

Overview

  • Los Angeles County recorded 165 hepatitis A cases in 2024, tripling the previous year's total and marking the highest count in over 10 years.
  • A community-wide outbreak was declared as cases continue to rise, with 29 confirmed in the first quarter of 2025—double the number from the same period last year.
  • The outbreak is spreading beyond traditional high-risk groups, with over 15% of 2024 cases occurring among individuals without housing risk factors.
  • Health officials are utilizing wastewater surveillance and genetic strain mapping to track the virus, which has also been detected in Orange and San Bernardino counties.
  • Public health efforts include intensified vaccination campaigns, particularly targeting vulnerable populations, and reinforcing hygiene practices to curb transmission.