San Diego County is facing a simultaneous public health challenge that has become tragically familiar to West Coast cities: rising hepatitis A and mpox case counts among residents experiencing homelessness, concentrated in downtown encampments where sanitation is inadequate, vaccine access is limited, and the conditions for rapid disease spread are persistently present. The San Diego County Public Health Department has confirmed ongoing hepatitis A surveillance activity among the county's unhoused population, while the hepmag.com national hepatitis tracker documents San Diego health officials as urging vaccinations amid rising hepatitis A and mpox cases as of late 2025, with concerns continuing into 2026.
San Diego County has more than 10,000 unhoused residents, one of the largest homeless populations in the United States relative to its overall size. The 2017 hepatitis A outbreak — which killed 20 people and infected more than 500 — originated in San Diego's homeless encampments and spread to the general population through a combination of poor sanitation and food handler exposure. Health authorities never want to repeat that outbreak, which drew national attention and became a case study in how preventable deaths occur when outbreak warning signs are ignored.
