Increase in Hepatitis A Cases With No History of Travel
March 7, 2019
The Orange County Health Care Agency has received 10 reports of acute hepatitis a virus (HAV) infection in Orange County residents since September 1, 2018. Median case age is 48 years (range 27-69 years); 5 females, 5 males; 50% self-report as Not-Hispanic or Latino/White. Eight of these cases reported no history of travel to areas with ongoing HAV transmission or exposure to a known case. One of the eight cases reported illicit drug use, none reported experiencing homelessness. No common social or geographic exposures have been identified. None report receiving hepatitis A vaccination in the past. Four cases with no history of travel have had genotyping performed, all were found to be infected with distinct HAV strains, indicating repeated introduction of HAV into the County.
  • HAV infection should be considered in persons with signs and/or symptoms of hepatitis, particularly in those who report a history of experiencing homelessness, injection or non-injection drug use, or men who have sex with men.
  • Providers should report any suspect or confirmed hepatitis A patients promptly to Orange County Public Health Epidemiology by phone at 714-834-8180 or by fax at 714-564-4050.
  • Patients suspected or confirmed to have hepatitis A should not be discharged to the street or to congregate settings while still infectious.
  • The Centers for Disease Control and Prevention (CDC) recommends HAV vaccination for all persons experiencing homelessness or a history of using illicit injection or non-injection drugs. Orange County providers should assure HAV immunization for patients with these risk factors.  
Symptoms and Transmission: 
  • HAV infection signs and symptoms include jaundice, dark urine, fever, malaise, anorexia, nausea, diarrhea, and abdominal discomfort, and increased transaminases (AST/ALT).
  • The incubation period for HAV infection ranges from 15–50 days. Most immunocompetent persons shed virus in the stool and are infectious from two weeks before through one week after the onset of jaundice.
  • HAV is generally transmitted through the fecal-oral route. Transmission occurs from close contact with a person infected with hepatitis A or exposure to feces-contaminated food, drinks, or other objects. 
Laboratory Testing:
  • HAV infection is diagnosed using Hepatitis A IgM serologic testing.
  • All patients with HAV infection should have serum forwarded to Orange County Public Health Laboratory to arrange for genotypic testing. Genotyping testing enhances public health surveillance and helps to identify outbreaks. 
  • Two doses of HAV vaccination are recommended for all children at one year of age, as well as persons with high risk conditions or behaviors including:
  • Users of illicit injection and non-injection drugs
  • Persons experiencing homelessness
  • Persons with chronic liver disease, including those with hepatitis B or C virus (HBV or HCV) infection
  • Men who have sex with men
  • Persons traveling to or working in countries that have high or intermediate levels of HAV transmission
  • Persons who have been exposed to HAV in the prior 2 weeks and are not known to be immune

In October, the CDC’s Advisory Committee on Immunization Practices (ACIP) added persons experiencing homelessness to the list of those at elevated risk of HAV who should receive vaccination, see for additional details.

For a summary of ACIP/CDC recommendations for HAV vaccination, see .
Contact Information
If you have any questions or concerns please contact the Epidemiology and Assessment Program at (714) 834-8180.
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