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Health Advisory: Hepatitis A Outbreaks in California; Prevention Recommendations

Published: December 21, 2017

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Actions Requested

Identify and immediately vaccinate non-HAV-immune patients who are:

  • Homeless, OR
  • Meet ACIP recommendations for routine HAV vaccine, including:
    • Injection or non-injection drug use
    • Chronic liver disease, including infection with hepatitis B or C
    • Men who have sex with men (MSM)
    • Anyone seeking protection from HAV.

If you provide off site medical care to homeless individuals, add hepatitis A vaccination to your care services.

When you provide hepatitis A vaccination, make sure to record it in the California Immunization Registry (CAIR) to assist with tracking of when next doses are due. Also follow-up with your clients to ensure they get the remaining doses.

Serological testing for HAV immunity is NOT recommended as screening before vaccination; instead, vaccinate those for whom you lack a record of serologic immunity or completed immunization.

Use monovalent HAV vaccine OR combined hepatitis A/B vaccine. However, note the 1st dose of monovalent HAV vaccine provides fuller protection than the 1st dose of combined hepatitis A/B vaccine, and is preferred for outbreak prevention if follow up is uncertain.

Also please provide basic hepatitis A information to clients, including transmission routes and prevention: See our flier at: .

Suspect acute hepatitis A in homeless and/or drug-users and/or MSM who present with consistent symptoms (abdominal pain, nausea, vomiting, fever, jaundice and significant elevation in LFTs). Confirm by obtaining a complete viral hepatitis serology panel.

Report cases of symptomatic, lab-confirmed hepatitis A infections by phone to Sonoma County Disease Control at 707.565.4566 while the patient is still at the healthcare facility so individuals can be interviewed and are not lost to follow-up. After hours, follow instructions to contact the on-call Health Officer.

Work with your institution's occupational health provider and with Sonoma County Disease Control to provide post-exposure prophylaxis to non-immune exposed individuals.

Situation - Updated December 21, 2017

Currently, we have no outbreak associated cases of hepatitis A in Sonoma County. However, several California counties (San Diego, Santa Cruz, and Los Angeles) continue to report outbreak associated cases of genotype IB strains of hepatitis A virus (HAV) among individuals who are homeless and/or using illicit drugs.

As of December 1, 2017, the California Department of Public Health (CDPH) reports 627 confirmed and probable cases including 21 deaths since November 2016. 18 outbreak-associated cases have been identified in other jurisdictions in California and additional cases are under investigation.

The outbreak is being spread person-to-person and through contact with environments contaminated by feces and is not associated with a contaminated food product.

In parallel, CDPH notes an increase of hepatitis A cases among MSM. Statewide, 56 MSM cases were identified to date in 2017 compared with 18 in 2016. 24 are genotype 1A, 7 are genotype 1B and 25 have unknown genotype. No recent case among MSM has been reported Sonoma County.

In Sonoma County we have an ongoing opportunity to prevent an outbreak through immunization, rapid recognition and response to initial cases and education about prevention through basic hygiene.


HAV is a highly infectious enteric virus that multiplies in the liver and is shed in the feces. HAV is a vaccine-preventable illness that can range in severity from a mild illness lasting a few weeks to a severe illness lasting several months or even death. The incubation period ranges from 15 to 50 days with a mean of 28 days. Symptoms include nausea, vomiting, diarrhea, anorexia, fever, malaise, dark urine, light-colored stool, and abdominal pain. A complete viral hepatitis serology panel is recommended in symptomatic patients. Serological testing for HAV infection is not recommended in asymptomatic individuals or as screening before vaccination.

Transmission and Prevention - Updated December 21, 2017

HAV is transmitted person-to-person and via food, water, or surfaces contaminated with feces. Most immunocompetent adults shed virus in the stool and are infectious from two weeks before through one week after the onset of jaundice. The primary strategies for outbreak control are vaccination and improving access to sanitation. Persons in Sonoma County are considered to be at risk of HAV infection at this time if they are a) homeless, or b) using or may be using illicit drugs of any type (injection or non-injection), or c) MSM, AND if they are not already immune by means of completed vaccination (2 doses of monovalent HAV vaccine or 3 doses of combined hepatitis A/B vaccine) or serology (total hepatitis A antibody positive).

California children have been recommended to receive hepatitis A vaccine since 1999. Therefore some young adults in the risk population may have been vaccinated and their immunization histories may be found in CAIR.

Health care and other workers who may have contact with hepatitis A cases, and who lack immunity or vaccination, should consider obtaining HAV immunization through their employer or health plan.

Post-exposure prophylaxis (PEP) with HAV vaccine (or in some cases, IM immune globulin) is effective in non-HAV-immune persons exposed to HAV in the prior 2 weeks:

Vaccine Access - Updated December 21, 2017

Earlier some vaccine supplies were constrained. Currently, vaccine is available. For both managed care and fee for service members, Medi-Cal covers hepatitis A vaccine without prior authorization both in providers' offices and at network pharmacies. For providers that have access to federally funded (317) or state funded vaccine, it should be used for the highest risk populations (persons who are homeless and/or use illicit drugs and/or are MSM). Whenever feasible, non-317 vaccine supplies should be used, and insurance should be billed.

Hepatitis B (HBV) vaccine is also recommended for injection drug users who are not known to be immune. A complete vaccination series is needed for full protection.


CDPH HAV webpage

CDC 2017 Adult Immunization Schedule

Hepatitis A Q&A for Health Professionals