Fears of an outbreak of a highly contagious disease have prompted King County to expand free hepatitis A vaccinations for people experiencing homelessness.

The vaccinations are part of an effort to prevent an outbreak like those seen in other West Coast cities, said Jeff Duchin, health officer for Public Health — Seattle & King County. In April, King County public-health officials diagnosed hepatitis A in a homeless man, the first such case locally.

“This is not a new initiative, this is new funding,” Duchin said of the $375,000 commitment announced Wednesday.

In 2017, an outbreak in San Diego that largely affected people experiencing homelessness left 20 dead and hospitalized 400. An audit found that slow response by the county in providing mass vaccinations allowed the outbreak to grow.

Several municipalities have seen hepatitis outbreaks in the recent months, including Phoenix and Boise.

The Seattle Times’ Project Homeless is funded by BECU, Campion Foundation, the Paul G. Allen Family Foundation, Raikes Foundation, Seattle Foundation and the University of Washington. The Seattle Times maintains editorial control over Project Homeless content.

In 2018, there were 14 reported cases of hepatitis A in King County. There have been 12 cases reported this year, including the one person living on the streets.


The program will target people experiencing homelessness because they are a sizable population at an increased risk for hepatitis A outbreaks, Duchin said.

Hepatitis A spreads through food or water contaminated by someone exposed to fecal matter containing the virus, said John Scott, an expert in viral hepatitis at UW Medicine. Crowding and lack of access to sanitation makes people experiencing homelessness vulnerable.

“We have a large population living in conditions that are favorable to hepatitis A outbreaks,” Duchin said.

Last March, King County officials voiced concerns about outbreaks of serious diseases among people experiencing homelessness.

In the past 18 months, King County has vaccinated 2,200 people against hepatitis A, but the goal is to reach a threshold that would prevent the virus from spreading among people experiencing homelessness, Duchin said.

Reaching that goal would require around a 90% vaccination rate, Scott said. Full protection from hepatitis A requires a second dose of the vaccine six months later, the length of the planned program.

However, even one dose can be effective for 10 years and offer 85% t0 90% protection, which could help blunt the potential of an outbreak.


As of February, the Centers for Disease Control and Prevention recommends the vaccine for all people experiencing homelessness. While it is now standard for most children to receive the vaccine, this practice only began relatively recently so most adults are still at risk.

The funding will allow the public-health agency to expand services with dedicated funding for a coordinator, administrative support and four part-time vaccinators. All of the new positions have been filled and will be starting next week, if they haven’t already.

If demand for the vaccines outstrips what they are able to provide, the county will seek additional funding from the state or county.