|Transmission within households|
|Residential institution transmission|
|Daycare center transmission|
|Transmission among military personnel|
|Contact with contaminated food or water|
|Consumption of raw or undercooked shellfish, vegetables, or other foods|
|Consumption of foods contaminated by infected food handlers|
|Illicit drug use|
- Cytotoxic cell injury, mediated by host immune system against infected Hepatocytes.
- Interferon-gamma appears to have a central role in promoting clearance of infected hepatocytes
- Usually self-limited illness.
- Symptoms- nausea, vomiting, abdominal pain, jaundice.
- Incubation period- 15 to 50 days
- Elevated enzymes (often >1000 IU/dL). (ALT>AST)
- Elevated bilirubin.
- Elevated ALP.
- Recovery from acute infection and normalization of lab values usually happen in 3 to 6 months.
Fulminant hepatic failure –> encephalopathy + INR >/= 1.5 + acute liver injury.
- Usually rare in acute HAV infection.
- Can occur in individuals with age >50 years, with other comorbidities like HBV or HCV.
- Cholestatic hepatitis-
- jaundice >3 months, with pruritis, fever, weight loss, diarrhea, malaise.
- Self-resolving with no sequelae.
- Treatment is only supportive. Cholestyramine can be given for pruritis.
- Relapsing hepatitis-
- Relapse of symptoms during 6 months of acute infection.
- The duration of clinical relapse is generally less than three weeks, although biochemical relapse may last as long as 12 months.
- Self-resolving, treatment is supportive.
- Autoimmune hepatitis-
- Rarely, Acute HAV infection, can be a trigger for autoimmune hepatitis.
- IgM antibodies for HAV.
- These are detectable at time of symptom onset and up to 3-6 months after infection.
- IgG antibodies are detectable in convalescence period and usually last for decades, and provides lifelong immunity.
- Medications causing liver injury should not be used.
- Full clinical and biochemical recovery usually occurs within 3 to 6 months.
- Patients with fulminant hepatic failure require aggressive supportive therapy and may require liver transplantation.
- Children 12 to 23 months.
- children and adolescents 2 to 18 years who were previously not vaccinated.
- Infants 6 to 11 months who are travelling to countries which have endemic HAV infections. the travel-related dose should not be counted toward the routine two-dose series.
- At risk adult populations- MSM’s, Chronic liver disease, HBV or HCV infected individuals, HIV infection, Injection drug users, homeless individuals.
Individuals who do not need routine vaccination against hepatitis A include:
- Food service workers (in the absence of an outbreak)
- Individuals who receive blood products for clotting disorders (eg, haemophilia)
Post exposure prevention-
- Exposure to HAV infected individuals. (household contacts, sexual contacts)
- Individuals who have shared illicit drugs
- Food handlers- if a food handler is tested positive, then other food handlers should be given post exposure protection.
- Postexposure prophylaxis is not warranted in association with a single case of hepatitis A in a school, office, or hospital if the source of infection is outside the school or work setting.
- HAVRIX – inactivated HAV vaccine.
- BioVac-A – live attenuated HAV vaccine.
Doses- 2 doses, at least 6-12 months apart.
- Immunoglobulin is given along with HAV vaccine in individuals with acute HAV infection or contact to HAV infected person if-
- Age >40 years.
- Age >12 months, and are immunocompromised or have chronic liver disease.
- Age <12 months and HAV vaccine is contraindicated (allergic reactions etc,.)
- Infants < 6months (HAV vaccine cannot be given)
- Dose- 0.1ml/kg I.M
- Centers for Disease Control and Prevention. Hepatitis A Questions and Answers for Health Professionals. http://www.cdc.gov/hepatitis/hav/havfaq.htm#vaccine (Accessed on October 05, 2016).
- Centers for Disease Control and Prevention. Health Information for International Travel 2020: The Yellow Book. https://wwwnc.cdc.gov/travel/page/yellowbook-home (Accessed on July 30, 2019).
- World Health Organization. Hepatitis A. http://www.who.int/mediacentre/factsheets/fs328/en/ (Accessed on February 17, 2017).
- HAVRIX IM injection, hepatitis A vaccine IM injection. GlaxoSmithKline, Research Triangle Park, NC 2011.
For further reading visit American society of gastroenterology.