The incubation period for HAV is 15 to 50 days. Fecal excretion of HAV is greatest during the incubation period of disease before the onset of jaundice. Once disease is clinically obvious, the risk of transmitting infection is decreased. However, some patients admitted to the hospital with HAV, particularly immunocompromised patients, may still be shedding virus because of prolonged or relapsing disease, and such patients are potentially infective. Fecal shedding of HAV, formerly believed to continue only as long as 2 weeks after onset of dark urine, has been shown to occur as late as 6 months after diagnosis of infection in premature infants.
Anicteric infection is typical in young children and infants.
Personnel can protect themselves and others from infection with HAV by adhering to standard precautions. Food-borne transmission of hepatitis A is not discussed in this guideline, but it has occurred in health care settings. Vaccine may be useful for personnel working or living in areas where HAV is highly endemic and is indicated for personnel who handle HAV-infected primates or are exposed to HAV in a research laboratory. The role of hepatitis A vaccine in controlling outbreaks has not been adequately investigated. Restriction from patient care areas or food handling is indicated for personnel with HAV infection.