Highlights
- Vaccination and hygiene are vital in preventing hepatitis A outbreaks worldwide.
- Hepatitis A remains a public health challenge, urging continuous vaccination and surveillance efforts.
Summary and Overview
Hepatitis A is a contagious liver infection caused by the hepatitis A virus (HAV), primarily transmitted through contaminated food or water via the fecal-oral route. It often causes symptoms like jaundice, fever, fatigue, and nausea, though many children are asymptomatic. The disease is usually self-limiting but can lead to severe complications such as fulminant hepatic failure, especially in older adults or those with liver disease. Diagnosis relies on detecting IgM antibodies, with molecular tests like RT-PCR aiding early identification. No specific antiviral treatment exists; care is supportive. Vaccination and improved sanitation have reduced incidence, but outbreaks persist, especially in high-risk groups and travelers. Global epidemiology shows declining childhood exposure in high-income countries, increasing adult susceptibility and outbreaks, highlighting the need for sustained vaccination and public health efforts.
Epidemiology and Transmission
HAV prevalence varies globally, influenced by sanitation and socioeconomic factors. While improved conditions have lowered childhood exposure, this has increased adult susceptibility, resulting in periodic outbreaks linked to travel and imported foods. Infection rates differ by demographics and regions, with higher incidence in certain ethnic and border populations. Transmission occurs mainly via fecal-oral contamination of food or water, close contact in high-risk groups, and oral-anal sexual practices. Coinfections and extrahepatic symptoms have been reported but are uncommon.
Clinical Presentation and Complications
After a 14–28 day incubation, hepatitis A typically begins with malaise, nausea, fever, and abdominal pain, progressing to jaundice and fatigue. Symptoms last about eight weeks. Children often have mild or no symptoms, whereas adults commonly experience acute hepatitis. Severe complications include fulminant hepatic failure (in under 1% of adults) and cholestatic or relapsing hepatitis. Extrahepatic manifestations such as rash, arthritis, and hematologic abnormalities affect 10–15% of patients. Pregnant women face increased risks of gestational complications. Transmission is mainly fecal-oral, with outbreaks linked to close contact in vulnerable populations.
Diagnosis
Diagnosis relies on detecting IgM anti-HAV antibodies via serologic tests, which confirm acute infection. RT-PCR can identify viral RNA early but is not routinely used. Clinical symptoms are nonspecific, so serology is essential. Various immunoassays such as ELISA and radioimmunoassays are employed, alongside patient history and risk assessment.
Treatment and Prognosis
There is no specific antiviral treatment; management is supportive with hydration, rest, and symptom relief. Antiemetics and cautious use of acetaminophen may be needed. Hospitalization is rare but necessary for severe cases or fulminant hepatic failure, which may require liver transplantation. Most patients recover fully within six months without chronic infection. Severe disease is uncommon but more likely in older adults and those with liver disease. Post-exposure prophylaxis with vaccine or immune globulin is recommended for at-risk individuals.
Prevention and Public Health Measures
Prevention centers on vaccination and improved sanitation and hygiene. Both inactivated and live-attenuated vaccines are effective, with universal childhood immunization programs reducing incidence significantly. Vaccination is recommended for children over one year, travelers to endemic areas, and at-risk adults. Public health strategies include surveillance, outbreak response, and promoting hygiene practices. The WHO coordinates global monitoring and supports national vaccination campaigns to achieve viral hepatitis elimination by 2030.
Research and Developments
Research has enhanced understanding of HAV’s unique virology and improved diagnostic methods, such as RT-PCR for early detection. Vaccination remains the primary control measure, with inactivated vaccines showing near 100% seroconversion and live-attenuated vaccines providing long-lasting immunity in some countries. No antiviral treatments are available, emphasizing prevention. Ongoing collaboration among clinicians and public health experts continues to refine strategies for screening, vaccination, and outbreak management worldwide.
The content is provided by Avery Redwood, Scopewires
