Travel-specific immunizations

(Second of three parts)

In the last issue, I covered routine immunizations, telling which ones and how many to get as well as when to get them prior to going on a journey. In this issue I will cover the recommended travel-specific immunizations worth considering before traveling abroad.

Hepatitis A: this is the most common vaccine-preventable travel disease. Immunization consists of two doses six to 12 months apart. The duration of protection is 10 to 20 years — and perhaps longer, but this is not yet proven.

Hepatitis B: this is a routine immunization for children, but, for the most part, adults have missed getting this school-age vaccine. Three doses given over six to 12 months should protect for 20 to 40 years. Five percent of the population does not respond to this immunization and needs to repeat the series if blood tests fail to show protective antibodies a year or so after completing a full immunization series.

Combined Hepatitis A/B: this immunization series follows the same timing as that for Hepatitis B, and, being a combination of both Hepatitis A and B vaccines, only three doses are needed instead of five.

Polio — A single dose is recommended for adults traveling to polio-endemic countries. Polio is on the rise again, having spread from just five countries in 2002 to over treble that in 2006, and it continues to spread unpredictably.

Meningococcal Meningitis — Meningococcus is a bacterium which can cause a devastating infection of the central nervous system or an even worse systemic illness, called meningococcemia. There are several areas around the world with recent epidemics, and this vaccine is even required by many universities in the United States for their incoming freshmen.

Typhoid Fever — Typhoid is spread by food and water. It does not always cause illness but has an approximate fatality rate of 1%, even if treated. The worldwide abuse of antibiotics has led to a tougher bacterium which is much harder to treat. Another reason for immunization is to avoid a “carrier-state,” like that of Typhoid Mary, who was never ill but killed other people when she infected them while making their meals. This vaccine is available as a shot or as a set of pills taken over a week.

Rabies: this is one of the worst diseases known to mankind. It is typically spread by the bite of dogs, cats, bats or monkeys, although other mammals can also transmit rabies virus. Once the symptoms begin, the disease is nearly invariably fatal. There is a vaccine if you have been exposed, but there are several good reasons for obtaining rabies preexposure immunization prior to travel: it decreases the number of postexposure vaccine doses needed, it buys a little time and it eliminates the need for Rabies Immune Globulin (RIG), part of the postexposure treatment.

There is a worldwide shortage of RIG, and some countries simply don’t have any. In such cases, travelers who need the vaccine would have to abort their trip to get treatment. There is also a concern about the safety and sterility of the vaccine and needles in developing nations where the risk of this disease is greatest. The preexposure series consists of three immunizations given over a 3- to 4-week period prior to departure.

Japanese Encephalitis: this disease is spread by mosquitoes, and, while it’s low-risk for most travelers, there is a one-in-three chance of dying with clinical cases and a one-in-two chance that survivors will be brain-damaged. Travelers spending more that three weeks in Asia, traveling during and just after the rainy season or spending a lot of time in rural areas should get this vaccine. The immunization series consists of three doses given over a 3- to 4-week period, ideally with the last dose being given a week prior to departure, if possible.

Cholera: there is no reason to take this vaccine. The World Health Organization does not endorse it anymore.

Gamma Globulin: there is no reason to take this painful shot anymore. It is not a vaccine but antibodies taken from other people’s blood, which is enough reason to give one pause. In reality, if you take the Hepatitis A vaccine, then gamma globulin is simply unnecessary (not to mention you can’t sit for a day! And it only lasts a few months. . .).

Determining which of these immunizations are right for you takes serious thought and highlights the importance of seeking professional and expert help before travel. A travel-medicine specialist will know about any disease outbreaks around the globe, what precautions to take and which vaccines to recommend. You can find a list of such specialists at the websites www.istm.org and www.astmh.org.

—Travel & Health is written by Alan M. Spira, M.D., DTM&H, FRSTM