TRAVEL MEDECINE or prevention and vaccination for travellers - September 2007

Interview with Professor Robert Steffen, Director of the Infectious Diseases Division of the Institut de Médecine Sociale et Préventive of the University of Zurich, Collaborating Centre of the World Health Organization and author of Tropimed®, the database for travel medicine professionals.

Tourism and business travel are continuously expanding. Prevention and treatment of diseases that may be contracted during travel are more and more important today. Each year, many thousands of Swiss seeking sunshine return from their travels with beautiful photos but also certain health issues seem to arise at this time. Proper preparation for travel thus means not overlooking possible sanitary risks. Vaccinations naturally should be considered by the consulting physician.

1. The first pleasure of travel is planning the trip. What advice can we give to travellers regarding vaccinations so that planning is still a pleasure?

In fact, travellers planning to visit developing countries should plan to be vaccinated relatively early. For people travelling outside of usual tourist itineraries or staying in developing countries, we often recommend vaccination against hepatitis B or rabies. Rabies vaccination requires two injections and hepatitis B vaccination requires three injections, and both of these vaccinations must be obtained over a minimum of 21 days. Oral vaccination against typhoid fever also requires time, each of three capsules must be taken in an interval of two days (i.e. days 1, 3, and 5). This becomes fully effective only ten days after the last capsule. It should also be noted that vaccines may cause side-effects. There may be some pain, and perhaps even a slight fever of short duration. It is best to be vaccinated four to six weeks before departure.
However, it is inaccurate to assume that vaccinations received immediately prior to departure are useless. Boosters for tetanus, diphtheria and polio should be had every ten years for many travellers, and are always effective immediately, just like the vaccination for hepatitis A, a form of viral jaundice contracted from food or drinks. Unless you're on a pilgrimage to Mecca, the only vaccination required to enter some countries in tropical Africa and several less-commonly visited countries in South America is the vaccination against yellow fever. This injection must be had ten days before arrival in the country.
For several years, travellers have been able to obtain information on vaccinations free of charge at the website http://www.safetravel.ch. This source of information is however inadequate for health professionals.

2. What advice about behaviour can be given to travellers in order to prevent possible sanitary or alimentary risks?

First, the old colonial adage about food that one should "peel it, cut it, cook it or forget it" still applies. This clearly reduces the risk of diarrhea. Studies show, however, that 98% of Swiss travellers succumb to delicious salad buffets or accept ice cubes in their drinks, some even eat raw oysters or tartar steaks in the tropics. As a matter of fact, it's often difficult for travellers to resist these temptations and eat only meals served at 60° centigrade minimum and eat only fruit that can be peeled. On the other hand, with the high frequency of diarrhea, it is certainly recommended to travel with necessary medications. We'll return to this in a moment.
There are also other areas in which travellers may choose to adopt enlightened behaviour. Sun bathing may result in serious sunburn and several tour organizers report that sunburn has forced many clients to spend several days in the shade in their hotel rooms. Casual sexual relations, above all with natives, are the source of sexually-transmitted diseases and not only gonorrhea, but also HIV, which, as everyone knows, leads to AIDS. Mosquitoes spread many diseases especially malaria at night and dengue fever in the day. This is why people must take precautions against mosquito bites--first, by protecting exposed skin as much as possible with clothing, and next by using a mosquito repellent on exposed bodily parts. Insecticide products may be sprayed on socks and other clothes.
For survival, it is fundamental to avoid accidents and reduce the consequences of any accidents that occur. Traffic accidents and swimming-related accidents are responsible for half of all Swiss traveller mortalities occurring in the third world. People should always wear a seatbelt when travelling by automobile or a helmet when riding a motorcycle or bicycle. At the beach, people should be aware of ocean currents.

3. According to your statistics, what are the diseases most likely to be contracted when travelling?

When travelling in developing countries, diarrhea is clearly the most frequently occurring illness. On the other hand, when travelling in North America and Western Europe, it is clearly constipation. Chills, for example with the flu, are also frequent. In tropical Africa, there is often malaria transmission, and in 90% of cases, this is Malaria tropica, which can be fatal. Among the infectious diseases that may be avoided by vaccination, influenza, hepatitis A and hepatitis B are indisputably the top three.

4. What are the most dangerous diseases?

I would like to emphasize once more that the primary causes of Swiss deaths in the third world are not infectious diseases, but traffic and bathing accidents. The infectious diseases may be prevented by vaccinations or preventive medicines. Among those that threaten travellers in developing countries, rabies is clearly the most dangerous. Once the symptoms appear, the chance of survival is zero. It may be prevented by three doses of vaccine before travelling or by an immediate treatment administered in a large medical centre as soon as possible after being bitten by a dog or having contact with a suspected animal.

Malaria is also often dangerous. Approximately 300 cases are reported each year by the Swiss. However, considering the number of unreported cases, it is estimated that approximately 700 Swiss are affected by malaria each year. Switzerland also counts a number of deaths each year due to malaria, but the number of people who have already died abroad is unknown.

5. When do you recommend seeing a physician after returning from a trip?

Every traveller with a fever who has just returned from a malaria-infested region is imperatively recommended to see a physician within 24 hours. The physician will perform a blood test to confirm or reject the diagnosis of malaria. One must also see a physician for persistent diarrhea and other health problems. On the other hand, it's not necessary to have a medical examination after each visit to the tropics, even for long stays.

6. Travel medicine has become a separate specialisation involving different branches of medicine. What is the explanation for this trend? Is this a new awareness or a necessity? And why?

In fact, travel medicine is interdisciplinary and is not limited to tropical medicine or infectious diseases. Many travellers go trekking to high peaks or go scuba diving, for example. Naturally, the body is subjected to special stresses. For people who are more risk prone than others, for example, pregnant women, malaria can be particularly dangerous and young children with diarrhea can dehydrate in just a few hours and the condition can become very serious. There are also people who have pre-existing diseases, for among senior citizens or people with congenital blood coagulation and for whom long distance flights may trigger thrombosis.

7. In addition to international sanitary regulations that we must adhere to, some countries like Switzerland provide "National Recommendations". Can you explain the reason for this?

The objective of international sanitary regulations is to prevent the spread of diseases to countries in which they are not prevalent or at least to limit the risk of spreading the diseases. The individual traveller's health is of little interest to the authorities in the countries that are visited, even if this formula seems convincing. The recommendations provided by the Recommandations du Comité d'experts en médecine des voyages (Expert committe for travel medicine) in collaboration with the federal public health office focus on the goal of providing all travellers with all recommendations for protection of health during travel in regions with special risks. The differences between the various national recommendations result from the fact that the same medications, for example anti-malaria medications, are not available in all countries.

8 Why is personal advice desirable in a travel medicine consultation?

In travel medicine, individual advice is required because travellers have different objectives and different medical problems may arise during a trip. Moreover, each traveller is different, a family with young children or a diabetic patient needs different recommendations compared to a business man planning to spend 48 hours at meetings in a luxury hotel in the capital city.

9. Vaccination against measles is now recommended for all travellers. Is this connected with the WHO goal of eradicating the disease?

During the last two years, small outbreaks of measles have appeared in Switzerland and numerous children and adults have been hospitalized. For some people, this disease even led to encephalitis which is an inflammation of the brain and this unfortunately left some of these patients with permanent consequences. It has been shown that the measles viruses specifically analyzed in Switzerland primarily match foreign sub-types, which means that they were imported from Asia and respectively Africa. This is why there is now increased vigilance to make sure that people under 40 years of age, at one time or another in their lives, are vaccinated two times with the MMR vaccine (measles, mumps, rubella). Protection of the Swiss population is a priority, but the WHO goal to eradicate measles is secondary since measles now appears most often among adults and much more often leads to complications in this age group.

10. Can you give some advice to physicians who do not specialise in travel medicine but who wish to acquire more extensive knowledge in this subject?

Swiss physicians have very diverse interests and not all are interested in travel medicine. In consultations in which issues related to travel medicine arise, less-informed physicians can refer their clients to a travel medicine centre or to a physician specializing in tropical medicine.
Adequate information is available for medical personnel on Tropimed®. This site is specifically designed for professionals in the medical and pharmaceutical branches. The database is continuously updated and it provides notices, for example, when new epidemics arise or when new knowledge becomes available, on the primary and side effects of medications.