From the Guidelines
Hepatitis A virus (HAV) is a highly contagious liver infection caused by a formalin-inactivated, cell-culture–derived virus that can be prevented through vaccination and good hygiene practices. The virus is primarily spread through the fecal-oral route, contaminated food or water, and close personal contact, making vaccination and hygiene essential preventive measures 1.
Key Characteristics of HAV
- HAV is a liver infection that does not cause chronic infection, unlike hepatitis B and C
- The virus is highly contagious and can be spread through contaminated food or water and close personal contact
- Vaccination is the most effective means of preventing HAV transmission among persons at risk for infection
Prevention and Management
- I recommend the hepatitis A vaccine for all children starting at age 12 months, travelers to endemic regions, men who have sex with men, people with chronic liver disease, and those who use illicit drugs. The vaccine is given as two doses 6-12 months apart, providing long-term immunity 1
- For post-exposure prophylaxis, hepatitis A vaccine should be given within 2 weeks of exposure, with immunoglobulin (0.1 mL/kg) added for those over 40, immunocompromised individuals, or those with chronic liver disease
- Treatment of acute HAV infection is supportive, focusing on hydration, rest, and avoiding hepatotoxic substances including alcohol and acetaminophen
Vaccine Efficacy and Duration of Protection
- Hepatitis A vaccines induce protective antibody levels among virtually all adults, with 94%–100% of adults having protective antibody levels by 1 month after the first dose, and 100% achieving protective levels after a second dose 1
- Kinetic models of antibody decrease among adults indicate that protective levels persist for >40 years 1
From the Research
Definition and Transmission of Hepatitis A Virus (HAV)
- Hepatitis A virus (HAV) is one of the most common infectious etiologies of acute hepatitis worldwide 2.
- The virus is known to be transmitted fecal-orally, resulting in symptoms ranging from asymptomatic infection to fulminant hepatitis 2, 3.
- HAV can also be transmitted through oral-anal sex 2 and other high-risk behaviors.
Symptoms and Diagnosis of HAV Infection
- Classic symptoms of HAV infection include fever, malaise, dark urine, and jaundice, and are more common in older children and adults 3.
- People are most infectious 14 days before and seven days after the development of jaundice 3.
- Diagnosis of acute infection requires the use of serologic testing for immunoglobulin M anti-hepatitis A antibodies 3.
Prevention and Treatment of HAV Infection
- Routine hepatitis A immunization is recommended in children 12 to 23 months of age, as well as for individuals at high risk of contracting the infection 3, 4.
- Immunization is also recommended for individuals at high risk of complications from hepatitis A, such as those with chronic liver disease or HIV infection 2, 3.
- The vaccine is usually recommended for pre- and postexposure prophylaxis, but immune globulin can be used in patients who are too young to be vaccinated or if the vaccine is contraindicated 3, 5.
Epidemiology and Public Health Impact of HAV Infection
- Over 150 million new infections of hepatitis A occur annually, with the majority of cases occurring in low- and middle-income countries 4.
- HAV infection is a significant public health challenge, with outbreaks occurring in the United States and elsewhere 6.
- Improving hygiene and sanitation, rapid identification of outbreaks, and fast and accurate intervention in outbreak control are essential to reducing HAV transmission 4.