A shift in the way hepatitis A outbreaks happen has Oregon public health officials working to redirect their prevention strategies toward homeless populations that now represent the most vulnerable group for infection.

Until recently, hepatitis A outbreaks were linked primarily to international travelers or foodborne outbreaks, and infections occurred mainly in children. The introduction of a hepatitis A vaccine in 1996 led to a steady decline in outbreaks particularly after states like Oregon began requiring immunization for school entry.

But national rates spiked in 2016 and 2017 with outbreaks affecting mainly adults over the age of 40, particularly those who were homeless.

“The homeless population just seems like the perfect setup for this transmission,” said Dr. Paul Cieslak, medical director for communicable diseases and immunizations at the Oregon Health Authority’s Public Health Division. “You’ve got people living without the benefit of running water and often without toilet or sewage.”

Hepatitis A is typically transmitted when someone ingests something that has been contaminated with the feces of an infected person. Symptoms include fever, fatigue, nausea, abdominal pain, dark urine, joint pain and jaundice. Most people recover with limited treatment, but complications can occur especially among people already in poor health.

The federal Centers for Disease Control and Prevention recorded 1,521 cases of hepatitis A in 2017 from California, Kentucky, Michigan and Utah. Of those, 57 percent had reported drug use, homelessness or both. As a result, the Advisory Committee on Immunization Practices recommended in October adding homelessness to the list of reasons why some should be vaccinated.

The outbreaks have resulted in more severe cases than in the past. In 2017, 71 percent of those infected had to be hospitalized with 3 percent dying from the disease. A year earlier, 42 percent were hospitalized, with less than 1 percent dying. CDC officials suggested that could be because more patients had hepatitis B or C infections as well, or because of other risk factors common to those who use drugs or are homeless.

Oregon has been vaccinating against hepatitis A longer than most states in response to historically high rates of infection. The number of infections in the state has dropped from nearly 3,000 cases in 1999 to a combined 103 cases from 2013 to 2017.

Through November, Oregon had seen only 20 cases in 2018, although there is sometimes a lag in reporting. Only four of those cases involved persons younger than age 40.

“Vaccination has knocked this disease down,” Cieslak said. “Many times adults get it from kids and we knocked it out of the child population with vaccination.”

Deschutes County has had five hepatitis A cases since 2014 and hasn’t recorded any in 2018.

But with the large outbreaks elsewhere, Oregon officials fear it could easily happen here. The Oregon Health Authority purchased additional hepatitis A vaccine this year and distributed it to several large county health departments with large homeless populations.

Jill Johnson, the immunization program coordinator for Deschutes County Public Health, said the county did not receive any additional vaccine this year, but has been offering the vaccine as part of its other outreach efforts with the homeless.

Multnomah County was already routinely screening people at its shelters for tuberculosis, and began offering the additional hepatitis A vaccines provided by the state at the same time.

“It really is a very effective vaccine, so that’s been our main push,” said Lisa Ferguson, who oversees the county’s communicable disease services team. “We’ve been trying to connect with homeless services providers and making sure people out in the field know what to be looking for.”

County health officials have talked extensively with health officials in San Diego about their outbreak and held a summit with homeless service providers to prepare for a possible outbreak in Portland.

“This is a preventable disease,” Ferguson said. “And vaccination is the way to prevent it.”

Oregon officials are now recording people’s housing status in its databases to better track what percentage of cases are occurring in the homeless.

“In 2018, in Oregon, it’s been zero,” Cieslak said. “It hasn’t struck there. I fear that when it does, it will spread like crazy.”

— Reporter: 541-633-2162, mhawryluk@bendbulletin.com