Background: Public Health is investigating a cluster of hepatitis A cases among King County residents. Cases have had onset of symptoms in early March. At this time, we have not identified common exposures or risk factors. Please be sure that all cases of hepatitis A are reported promptly to Public Health at 206-296-4774.

Hepatitis A is transmitted person-to-person transmission through the fecal-oral route or through contaminated food or water. Signs and symptoms of hepatitis A include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, clay-colored bowel movements, joint pain, and jaundice. Some persons, particularly young children, are asymptomatic. The average incubation period for hepatitis A is 28 days (range: 15–50 days).

The diagnosis is established by testing for hepatitis A IgM in serum. Ruling out acute hepatitis B and C is also recommended in persons with suspected acute infectious hepatitis

Prevention: Hepatitis A is prevented through vaccination. The following groups should be vaccinated against hepatitis A:

• All children at age 1 year (i.e., 12–23 months). Children who have not been vaccinated by age 2 can be vaccinated at subsequent visits.
• Persons traveling to or working in countries that have high or intermediate rates of hepatitis A. The risk for hepatitis A exists even for travelers to urban areas, those who stay in luxury hotels, and those who report that they have good hygiene and that they are careful about what they drink and eat.
• Men who have sex with men.
• Users of illegal injection and noninjection drugs.
• Persons who work with HAV-infected primates or with HAV in a research laboratory.
• Persons who have chronic liver disease who have never had hepatitis A should be vaccinated.
• Persons who have clotting-factor disorders.

Public Health – Seattle & King County Hepatitis A fact sheet

CDC Hepatitis A fact sheet

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