One Shot of Hep A Vaccine Can Stop Outbreak

County nurse Paulina Bobenrieth vaccinates a patient in downtown San Diego.

Vaccinating members of at-risk groups with one shot of hepatitis A vaccine is enough to be able to stop the ongoing outbreak in San Diego County.

This was one of the main messages of a news conference at Infectious Disease Week, an annual gathering of health care professionals taking place in San Diego.

“Vaccination is the most important component,” to contain a hepatitis A outbreak said Monique Foster, M.D., M.P.H., medical epidemiologist at the Centers for Disease Control and Prevention. “The hepatitis A vaccine is 90 percent effective and that is the most effective way to control an outbreak. Vaccination is key because it offers protection right then.”

Dr. McDonald, left, and Dr. Foster discuss the hepatitis A outbreak.
Dr. McDonald, left, and Dr. Foster discuss the hepatitis A outbreak.

The CDC recommends two doses of the hepatitis A vaccine, six months apart, for those at higher risk of contracting the virus. But to stop an outbreak, one dose is all that is needed.

Foster was joined by Eric McDonald, M.D., M.P.H., medical director of the County Health and Human Services Agency’s Epidemiology and Immunization Branch. Both doctors agreed that vaccinating the at-risk groups will help to stop the hepatitis A outbreak, though it could take up to one year or more to return to pre-outbreak or expected levels.

At-Risk Groups

“Getting the vaccine to the target defined, at-risk groups is essential,” said McDonald, adding that good hand hygiene and education could also help to put an end to the hepatitis A outbreak that started in November of last year.

During this outbreak, the people who are most at risk are homeless people or users of injection or non-injection illegal drugs. People who work with or clean up after homeless individuals and/or users of illegal drugs are also at risk. Vaccination efforts should also continue to other established at-risk groups and those who have been recently recommended to get vaccine due to the outbreak.

The risk groups identified by CDC since 2006 include:

  • Users of injection or non-injection illegal drugs
  • Men who have sex with men
  • People with chronic liver disease, such as cirrhosis, hepatitis B or hepatitis C
  • Travelers to countries with high or medium rates of hepatitis A virus
  • People with clotting factor disorders

Because of the ongoing hepatitis A outbreak, the County Health and Human Services Agency is also recommending that the following people be vaccinated as well:

  • People who are homeless
  • People who work on a close and ongoing basis with or clean up after homeless individuals and/or users of illegal drugs
  • Food handlers

Since vaccination efforts began in early March, more than 54,000 vaccinations have been given across the county, including almost 12,000 by nurses on foot teams or field events at specific locations such as homeless service providers or substance use disorder treatment facilities.

County nurse Jeanina Rumbaoa vaccinates a patient outside a public restroom.
County nurse Jeanina Rumbaoa vaccinates a patient outside a public restroom.

“The unique approaches we are using are helping us increase vaccinations to those who need it the most,” McDonald said.

Also, more than 6,000 hygiene kits have been distributed and 98 hand-washing stations have been placed throughout the region. The kits include hand sanitizer, cleansing wipes, bottled water, a waste bag and information on preventing hepatitis A.

Low Risk for General Population

The hepatitis A vaccine is not being recommended for the population at large.

“There is very low risk of contracting hepatitis A for the general population,” McDonald said. “We are not recommending vaccination for adults who are not in the at-risk groups, though hepatitis A is a routine childhood vaccination.”

Through September there have been 481 hepatitis A cases tied to the outbreak, including 17 deaths and 337 hospitalizations. There are currently 47 cases under investigation, including one death.

The ages of the people who contracted hepatitis A range from 5 to 87 years. The 5-year-old had not received the hepatitis A vaccine, which has been recommended for children at 12 and 18 months of age since 1999 in California.

Hand washing with soap and water can help to stop the spread of hepatitis A.
Hand washing with soap and water can help to stop the spread of hepatitis A.

The majority of the cases have been reported in the homeless or illicit drug use population. The breakdown is:

Homeless/illicit drug use status is as follows:

  • 160 (33 percent) homeless and illicit drug use
  • 80 (17 percent) homeless only
  • 58 (12 percent) illicit drug use only

There have also been 125 (26 percent) cases in people who were neither homeless nor illegal drug users, but, McDonald said, most had shared restroom facilities or had a connection to the homeless or drug-using population. There are 58 cases (12 percent) for which no records or interviews exist.

Enough Vaccine

Foster, the Centers for Disease Control and Prevention medical epidemiologist, said there is no hepatitis A vaccine shortage right now, even given the increased demand. She said the CDC has enough vaccine and has been sending it to the jurisdictions that are currently experiencing hepatitis A outbreaks.

“There is enough vaccine to combat these outbreaks,” Foster said.

Hepatitis A is most commonly spread person-to-person through the fecal-oral route. Symptoms of hepatitis A include jaundice (yellowing of the skin and eyes), fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, and light-colored stools.  Symptoms usually appear over a number of days and last less than two months.  However, some people can be ill for as long as six months. Hepatitis A can sometimes cause liver failure and even death.

For general information on hepatitis A, visit the HHSA hepatitis website where data are updated routinely. A hepatitis A fact sheet is also available.


José A. Álvarez is a communications specialist with the County of San Diego Communications Office. Contact