Can I Be Vaccinated Against Hepatitis A? |
Hepatitis A may also be avoided through vaccination with immune globulin (IG) - or hepatitis A vaccine. IG contains antibodies (or protective proteins) to the hepatitis A virus. IG is relatively inexpensive and provides short-term protection against hepatitis A disease (generally 3 to 5 months).
Hepatitis A vaccines also help provide longer-term protection against hepatitis A. The total duration of protection is unknown at present, but in one study, protection was demonstrated for at least 4 years. Studies are ongoing. The vaccines contain a killed or inactivated virus that does not cause hepatitis A, but does stimulate the body's immune system to make the antibodies that help protect against the virus.
Immunoglobulin and Hepatitis A
Until recently, only immunoglobulin was available to protect at-risk groups from infection by the hepatitis A virus. Immunoglobulin is safe and provides immediate protection, but that protection lasts for only four to six months. Those who travel often or stay abroad for long periods need frequent repeat doses of immunoglobulin.
Now a new longer-lasting vaccine is licensed for use in Canada. The vaccine, which has been used in Europe since 1992, contains inactivated hepatitis A virus. Antibodies appear two weeks after administration, and antibody levels are much higher that those with immunoglobulin.
A patient should receive two doses of the vaccine, given two to four weeks apart. This dosage schedule offers protection for at least one year. A third booster dose can be given six to 12 months later to ensure long term protection.
In those planning to travel to an endemic area in less than a month, HAV vaccine and immunoglobulin can be given at the same time. The HAV vaccine and immunoglobulin should be administered using separate syringes and at different injection sites. This way protection is immediate and long-term. Hepatitis A vaccine can also be given at the same time as hepatitis B vaccine, again using different syringes at different sites.
How Effective Is It?
Studies have shown that the new HAV vaccine provides almost 100% protection against HAV in both adults and children when two doses are given one month apart. One very large study was done in Thailand, and included communities where HAV is very common. The study comprised 40,199 children between the ages of one and 16 years. Of these, 38,157 were followed after vaccination, and 33,586 completed 18 months of follow-up. The vaccine was 94% effective in preventing symptomatic illness after two doses.
Studies also show the new HAV vaccine is well tolerated. There have been few side effects, and those that have occurred have been minor. The most common one is a slight soreness at the injection site, experienced by about one-third of adults.
Who Should Be Vaccinated?
Currently the vaccine is indicated only for people at risk of contracting HAV. These include those born and raised in Australia, New Zealand, North America or Western Europe, who travel to or live in third world countries. Other at-risk groups are IV drug users, those who have many sexual partners and practice anal intercourse, workers in daycare centers or other child care institutions, sewage workers, foreign aid workers , medical personnel, food handlers, and military personnel on foreign postings.
In rare instances HAV infection is spread by blood and blood products, and so vaccination has been suggested for hemophiliacs and others receiving many transfusions.
Finally, as with hepatitis B, hepatitis A is unlikely to be eradicated by targeted vaccination policies. It appears that the optimal strategy for disease eradication will be universal vaccination.
Is vaccination safe?
Vaccines against hepatitis A are generally well tolerated. There may be pain, redness, tenderness, warmth, and irritation<