Hepatitis A

Order serum IgM anti-HAV when a patient is symptomatic and acute hepatitis A is in the differential; obtain ALT and total bilirubin concurrently to define hepatic injury and severity. CDC advises against using IgM anti-HAV as a screening test in asymptomatic persons because false-positive or clinically misleading results occur when pretest probability is low. CDC+1CDCClinical Screening and Diagnosis for Hepatitis A | Hepatitis A | CDCpublications aapHepatitis A | Red Book - AAP Publications

In acute hepatitis, do not stop at an HAV result when the presentation is severe, atypical, or discordant. Obtain competing viral hepatitis serologies, including hepatitis A through E where clinically indicated, and autoimmune serologies promptly in suspected acute liver failure. aasldaasldManagement of Acute Liver Failure | AASLD A symptomatic viremic patient can transiently have nonreactive IgM anti-HAV, so a negative result does not exclude HAV during an early compatible illness; reassess timing and alternative etiologies rather than treating one assay as definitive. fdafdaHepatitis A Virus Serological Assays - Class II Special Controls Guidance for Industry and FDA Staff | FDA

Confirm and report clinically compatible cases through local or state public health channels. Hepatitis A is nationally notifiable, and public-health confirmation of true cases is important because an erroneous positive IgM result can trigger unnecessary contact investigations and prophylaxis efforts. PubMed+1PubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI BookshelffdaHepatitis A Virus Serological Assays - Class II Special Controls Guidance for Industry and FDA Staff | FDA

Patients with acute hepatitis and encephalopathy require urgent management as suspected acute liver failure, regardless of whether HAV IgM is positive. AASLD emphasizes that acute liver failure hinges on an acute hepatic insult plus encephalopathy; obtain viral hepatitis serologies including A-E and autoimmune serologies promptly while arranging higher-level care. aasldaasldManagement of Acute Liver Failure | AASLD

Treat HAV-associated acute liver failure with supportive care because no virus-specific treatment has proven effective. aasldaasldPosition Paper: The Management of Acute Liver Failure Early referral to a liver transplant center is critical when acute liver failure is suspected, since transplant eligibility and timing can materially determine prognosis. aasld+1aasldManagement of Acute on Chronic Liver Failure in the Hospitalized ...aasldManagement of Acute Liver Failure | AASLD

Older age and underlying chronic liver disease should lower the threshold for close observation and early escalation. Reported U.S. hepatitis A case-fatality was 0.3% overall, increasing to 1.8% among adults older than 50 years; chronic liver disease is also associated with increased fulminant HAV risk. ScienceDirect+1ScienceDirectHepatitis A - an overview | ScienceDirect TopicsCDCUpdate: Prevention of Hepatitis A After Exposure to Hepatitis A Virus and in International Travelers. Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP)

Provide supportive care for uncomplicated hepatitis A. PubMed+1PubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI BookshelfPubMedFrom hepatitis A to E: A critical review of viral hepatitis Reassess clinically and with liver biochemical tests when symptoms worsen, jaundice deepens, oral intake is inadequate, or mental status changes; the latter requires immediate acute-liver-failure escalation rather than routine follow-up. CDC+1CDCClinical Screening and Diagnosis for Hepatitis A | Hepatitis A | CDCaasldManagement of Acute Liver Failure | AASLD

Counsel patients and households that infection is reportable and that contact management is time-sensitive. Public-health involvement is operationally important for identifying exposed persons and directing outbreak response; false-positive index-patient testing can otherwise create unnecessary investigations. fda+1fdaHepatitis A Virus Serological Assays - Class II Special Controls Guidance for Industry and FDA Staff | FDAPubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI Bookshelf

Do not label persistent liver test abnormalities as chronic hepatitis A without reassessing the diagnosis or considering relapsing illness and other liver diseases. Chronic hepatitis A does not occur. ScienceDirectScienceDirectHepatitis A - an overview | ScienceDirect Topics

For exposed, susceptible persons aged 12 months or older who have not completed the HepA vaccine series, administer one dose of single-antigen hepatitis A vaccine as soon as possible, ideally within 14 days after exposure. PubMedPubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI Bookshelf Do not delay indicated prophylaxis for routine preexposure serologic testing. PubMedPubMedHepatitis A Vaccine - StatPearls - NCBI Bookshelf - NIH

Add intramuscular immune globulin at 0.1 mL/kg to vaccine PEP for exposed persons who are immunocompromised or have chronic liver disease. For persons older than 40 years, decide whether to add IG using an individualized risk assessment that includes age, immune status, underlying conditions, exposure type, transmission risk, and IG availability. PubMed+1PubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI BookshelfPubMedPrevention of Hepatitis A Virus Infection in the United States - PMC

If HepA vaccine is contraindicated, administer IG 0.1 mL/kg as soon as possible within 14 days of exposure. PubMedPubMedPrevention of Hepatitis A Virus Infection in the United States - PMC Use single-antigen HepA vaccine rather than the combined HepA-HepB product Twinrix for PEP because PEP data for Twinrix are unavailable. PubMedPubMedPrevention of Hepatitis A Virus Infection in the United States - PMC

Use the routine two-dose IM HepA vaccine series beginning at age 12 months, with doses separated by 6 months; adults can also receive a two-dose series. PubMedPubMedClinical progress note: Hepatitis A virus - PMC For adults needing both HAV and HBV prevention outside the PEP setting, the three-dose combined HepA-HepB vaccine series is an option, but it should not replace single-antigen vaccine for PEP. PubMed+1PubMedClinical progress note: Hepatitis A virus - PMCPubMedPrevention of Hepatitis A Virus Infection in the United States - PMC

Vaccinate travelers and other persons at increased risk, including those with chronic liver disease. ScienceDirect+1ScienceDirectHepatitis A - an overview | ScienceDirect TopicsPubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI Bookshelf For infants aged 6-11 months traveling outside the United States, CDC guidance includes a specific travel-vaccination recommendation. PubMedPubMedPrevention of Hepatitis A Virus Infection in the United States - PMC In people with HIV, vaccinate those without HAV antibody regardless of CD4 count rather than deferring vaccination for immune reconstitution. PubMedPubMedPrevention and Management of Hepatitis A Virus Infection in Adults With HIV - NCBI Bookshelf

Do not routinely perform prevaccination serology. Consider total anti-HAV or IgG anti-HAV testing only when avoiding vaccination of persons already immune would materially affect cost or program implementation; a positive total or IgG anti-HAV with negative IgM indicates immunity from prior infection or vaccination. CDC+1CDCClinical Screening and Diagnosis for Hepatitis A | Hepatitis A | CDCPubMedHepatitis A - CDC Yellow Book, 2026 edition - NCBI Bookshelf