Taking vaccines is good medicine for traveling

Donya Betancourt, Pediatrician, drdonya@hotmail.com

Doctors recommend vaccinations for people traveling to places where certain diseases are prevalent. This precautionary measure should become part of a traveler's planning.

They are advised to consult a travel medicine clinic or personal physician between four to six weeks before departure if the travel destination is one where exposure to vaccine- preventable diseases may occur.

The vaccines that may be recommended or considered for travelers are as follows.

Routine vaccination: Diphtheria/tetanus/pertussis (DTP), Hepatitis B (HBV), Haemophilus influenzae type b (Hib), measles (MMR), poliomyelitis (OPV or IPV)a.

Selective use for travelers: Cholera, influenza, hepatitis A (HAV), Japanese encephalitis, lyme disease, meningococcal meningitis, pneumococcal disease, rabies, tick-borne encephalitis, tuberculosis (BCG), typhoid fever, yellow fever (for individual protection).

Mandatory vaccination: Yellow fever (for protection in vulnerable countries), meningococcal meningitis (for haj, umroh pilgrims).

I have left out the schedule for the administration of each vaccine. Time intervals for administration of vaccines requiring more than one dose are recommended; some slight variation can be made to accommodate the needs of travelers who may not be able to complete the schedule exactly as recommended.

In general, it is acceptable to lengthen the time intervals between doses, but significant shortening of the intervals is not recommended.

The route of administration differs for individual vaccines and is critical for induction of the protective immune response. All commonly used vaccines can be given simultaneously at separate sites at least 2 cm apart.

However, certain vaccines commonly cause local reactions, which may be accentuated if a number of vaccines are given simultaneously. If possible, these vaccines should be given on separate occasions unless financial and time constraints dictate otherwise.

A number of combined vaccines are now available, providing protection against more than one disease, and new combinations are likely to become available in future years.

For routine vaccination, the combined diphtheria/tetanus/pertussis (DTP) and measles/mumps/rubella (MMR) vaccines are in widespread use in children.

Other examples of currently available combination vaccines are hepatitis A+B and hepatitis A + typhoid. In addition, other combination vaccines are available in certain countries. These include IPV+DTP, IPV+DTP+Hib and IPV+DTP+HepB+Hib.

In adults, the combined diphtheria-tetanus vaccine (with reduced diphtheria-Td) is generally used in preference to monovalent (single-disease) vaccine.

Combined vaccines offer important advantages for travelers, by reducing the number of injections required and the amount of time involved, so aiding compliance. Combination vaccines are just as safe and effective as the individual single-disease vaccines.

Most of the vaccines that are routinely administered in childhood require periodic booster doses throughout life to maintain an effective level of immunity. Adults in their country of residence often neglect to keep up the schedule of booster vaccinations, particularly if the risk of infection is low.

Some older adults may never have been vaccinated at all. It is important to realize that diseases such as diphtheria and poliomyelitis, which no longer occur in most industrialized countries, may be present in those visited by travelers.

Pretravel precautions should include booster doses of routine vaccines if the regular schedule has not been followed, or a full course of primary immunization for people who have never been vaccinated.

Mandatory vaccination, as authorized by international health regulations, nowadays concerns only yellow fever. A yellow fever vaccination is carried out for two different reasons: first, to protect the individual in areas where there is a risk of yellow fever infection; and second, to protect vulnerable countries from importation of the yellow fever virus.

Travelers should therefore be vaccinated if they visit a country where there is a risk of exposure to yellow fever. They must be vaccinated if they visit a country that requires yellow fever vaccination as a condition of entry. This applies to all travelers who arrive from (including airport transit) a country where yellow fever is endemic.

Vaccination against meningococcal disease is required by Saudi Arabia for pilgrims visiting Mecca for the haj and is also required by some countries for returning pilgrims.

Travelers should be provided with a written record of all vaccines administered (patient-retained record), preferably using the international vaccination certificate (which is required in the case of yellow fever vaccination).