What is Hepatitis A and Should I be Vaccinated?
Hepatitis A is a virus (HAV) that is spread through fecal oral contamination, tends to occur in clusters, and accounts for about 50% of the cases of hepatitis in the US each year. It is typically passed hand to hand and through food from infected food handlers.
Who gets sick from it?
Many people have been exposed to hepatitis A and don’t know it. Ninety percent of infections in children younger than 5 have no clinical symptoms. With children’s hygiene habits, you can imagine how quickly this can spread child to child. A person can only be infected once, so a subclinical infection at this early age is protective for life.
Unfortunately, if a person is not exposed as a child, their likelihood of becoming ill with HAV if exposed worsens as they age. The case fatality rate of adults over 50 is 2.7%. You may remember the 1993 outbreak in Nome where several people died. This is a case of an increased health risk due to improved standards of hygiene and sanitation. Now there is a population of susceptible adults and older children who were not given the “advantage” of subclinical disease when young.
Is it in Alaska?
Hepatitis A is a reportable disease which allows the Department of Health and Social Services, State Epidemiology office to keep statistics and intervene in and limit outbreaks. This office is available for contact investigation, immunoglobulin treatment, etc.
What’s the vaccine about? Does it work?
Switzerland first started using the vaccine in 1991 and it is available in 30 countries now. It is given as one vaccination and provides immunity in at best 8 - 10 days. The titre becomes positive in nearly 99% of individuals in a month and this test usually remains positive for at least 12 months. A booster dose 6 - 12 months later may provide longer protection. The duration of protection is currently unknown. It probably lasts 2-3 years and may last to 20 years. It’s efficacy is uncertain as well, but one study of children showed a 94% efficacy rate for the prevention of clinical hepatitis.
What are the side effects and contraindications?
The vaccine is an inactivated whole virus vaccine containing the viral antigen, aluminum hydroxide, and 2-phenoxyethanol and is contraindicated in anyone with known hypersensitivity to any component of the vaccine. Side effects in early clinical trials of both include:
- soreness at injection site 56%
- transient redness and swelling <5%
- headache 14%
- severe headache 0.6%
(there was one case of Guillian-Barre thought not associated with the vaccine) Reactions and rates were very similar to the booster.
Who is it recommended for?
It is currently indicated in the following:
- travelers to areas of higher endemicity
- military personnel
- people living in or moving to areas of high endemicity
- certain ethnic and geographic populations that experience cyclic hepatitis A epidemics such as native peoples of Alaska and the Americas
- others such as persons engaging in high-risk sexual activity (such as homosexual males), users of illicit injectable drugs, residents of communities experiencing an outbreak.
It may also be used in other specific populations such as:
- day care workers
- lab workers handling live HAV
- handlers of primates that may have HAV
**Note, health care workers are not included here and this is not legally required. We have vaccinated our employees because of concern for their well being, as well as their becoming potentially infectious to out-patients.