As a follow-up to last issue's immunization update and a lead-in to the summer season, I want to review vaccinations HIVers will need when traveling abroad (starting with the assumption that your most basic immunization, tetanus, is current).
Hepatitis A. This fecal virus can easily be picked up through eating and drinking. The vaccine is usually given as part of the standard set of immunizations for HIVers and can last up to 20 years. However, the vaccine is less effective if administered when your CD4 count is less than 100. If testing shows you have hepatitis A antibodies, you're OK. However, a negative antibody result doesn't mean inadequate immunity, since some patients can get protection without producing detectable levels of antibodies. Double-check when you got the vaccine and what your CD4 count was at the time. If in doubt, it doesn't hurt to revaccinate. About 75% of patients will have protective antibodies within two weeks.
Influenza. The flu season runs April to September in the Southern Hemisphere and all year round in the tropics. The protection from our flu shot in the fall is mostly gone by now. Consider getting a second shot if you have respiratory problems. The vaccine is less effective in people with a CD4 count below 100, but it is still safe to give and will not affect viral loads or CD4 counts.
Yellow Fever. This mosquito-carried viral illness exists in most of Africa and South America below the equator. The vaccine contains a live virus and generally should not be given to HIVers. However, in someone with a high CD4 count who cannot avoid significant exposure, the vaccine can be given. Otherwise, in yellow fever areas it is recommended for travelers to use the usual mosquito precautions. You will also need a waiver letter from your health care provider documenting why the vaccine was not given.
Polio. This disease was nearly eradicated worldwide until vaccination programs were halted in Islamic regions in sub-Saharan Africa. Then there was a resurgence across Muslim countries all the way to Indonesia. Vaccination programs have been restarted, and the disease is now found primarily in Nigeria, India, Pakistan, and Afghanistan. Because childhood polio immunity may be fading, it is recommended to revaccinate with injectable polio vaccine. The oral form is live and not safe.
Typhoid. Typhoid is spread through contaminated water. Vaccination is not needed for most travelers unless access to purified or bottled water cannot be guaranteed'or for people whitewater rafting who might get a mouthful. As with polio, the injectable vaccine is inactivated and safe, but the oral form is live and not safe.
MMR. Measles, mumps, and rubella are much more common in developing countries. It is easy to check antibody levels to confirm continued immunity from childhood vaccination. Although this is a live attenuated (weakened) viral vaccine, it is safe to give if the recipient's CD4 count is over 200. The components can be given individually.
Meningitis. Meningococcal meningitis occurs in sub-Saharan Africa from January through April. There are also sporadic outbreaks worldwide. Vaccination is required for travel to Mecca for the hajj. It is also becoming standard in this country for students, especially those living in dormitories.
Chicken pox. This is a live-virus vaccine and is not considered safe for HIVers.
For people going to more exotic places or engaging in more extreme adventures, other vaccines, such as those for Japanese encephalitis or rabies, are also safe. The best place for further information is www.cdc.gov/travel. This site can give you information on recent outbreaks around the world and has a section for 'The Immunocompromised Traveler' from the 'Special Needs Travelers' link.
Remember, it can take a week or two to get test results back if you first check your antibody levels. Then it can take at least two weeks for shots to work. So allow yourself time. And don't forget your sun block.