Preventing Hepatitis A and B Together

Travelers destined for locations where hepatitis is a risk are urged to protect themselves with two separate vaccines for hepatitis A and B. This usually requires five injections over six months.

Soon a combination vaccine, requiring just three injections over six months, may be available in the U.S. to protect against both types of the potentially fatal liver diseases.

The combination vaccine, called Twinrix, is already available in 37 countries, including Canada and Mexico, according to SmithKline Beecham, its manufacturer. The company is awaiting Food and Drug Administration approval to market it here as well. That could come as early as this summer, travel medicine experts predict.

Since Twinrix went on the market in 1996, about 2.4 million doses have been given worldwide, according to SmithKline Beecham.

In a manufacturer-sponsored study, presented late last year at the Interscience Conference on Antimicrobial Agents and Chemotherapy, the combination vaccine provided protection similar to the separate vaccines.

In the study, 773 people were given either the combination or the separate vaccines, and then blood samples were collected to check levels of antibodies formed against the hepatitis viruses. The antibody responses in both groups were similar. Both groups also reported similar minor side effects, such as soreness at the injection site.

The federal Centers for Disease Control and Prevention has not yet addressed whether travelers should consider the combination instead of the separate vaccines.

Earlier this year, the International Society of Travel Medicine hosted a media teleconference to publicize the importance of travelers protecting themselves against hepatitis but stopped short of endorsing any specific vaccine.

Hepatitis A is transmitted by person-to-person contact or by ingesting contaminated water, ice or foods such as raw fruits or vegetables contaminated during handling. It is common throughout the developing world, and the CDC warns that the risk of infection increases with the duration of travel and is higher in rural areas.

Travelers to North America (except Mexico) and to developed countries are at no greater risk of infection than they are at home in the United States, the CDC says.

For those at risk, two hepatitis A vaccines, Havrix and Vaqta, are available in the U.S. Both require two doses for adults, given over a six-month or sometimes one-year period.

Symptoms of hepatitis A include fever, nausea, abdominal discomfort and loss of appetite. A few days later, jaundice can appear. Hepatitis A can be mild, going away in two weeks or so, or can become severely disabling and last much longer.

Symptoms of hepatitis B, mainly transmitted through sexual activity or activities that result in the exchange of blood or blood-derived fluids, are similar to those for hepatitis A: loss of appetite, nausea, abdominal discomfort and jaundice.

Hepatitis B infection risk is high in Africa, Southeast Asia, the Middle East (except Israel), southern and western Pacific islands, the interior Amazon Basin, Haiti and the Dominican Republic. The risk is moderate in south central and southwest Asia, Israel, Japan, Russia, Eastern and Southern Europe and most of Central and South America. The risk in Mexico is low, but it is high in parts of Alaska.

The CDC recommends that travelers going to at-risk areas for six months or less consider the vaccine if they will have direct contact with blood, such as in medical work, or sexual contact with locals.

In the U.S., two hepatitis B vaccines, Recombivax HB and Engerix-B, are available. Both are usually given as three injections over six months. Even if travelers don’t have the six months required before departure to obtain the full protective effect, the CDC still recommends the vaccines because some protection is offered by one or two doses.

Protection can be assumed four weeks after receiving one dose of hepatitis A virus, according to the CDC, although the second dose is needed for long-term protection.

For more information, see the CDC Web sites https://www.cdc.gov/travel/diseases/hav.htm and https://www.cdc.gov/travel/diseases/hbv.htm.

Healthy Traveler appears on the second and fourth Sundays of the month. Kathleen Doheny can be reached at kdoheny@compuserve.com.