Some 10'000 clients visit the Travel Clinic of the Swiss Tropical Institute every year for pre-travel advice. The counselling is based on the growing body of evidence-based data and on long-term experience of the five physicians working at the Institute. The recommendations are also based on the consensus of the Expert Committee for Travel Medicine, a group consisting of representatives of the leading travel clinics in Switzerland (Genève, Lausanne, Bern, Basel and Zürich), the Swiss International Airlines, experts from Germany, Austria, France and England, and the Swiss Federal Office of Public Health. The latter publishes updated lists of recommended vaccinations and malaria prevention in their bulletin at least three times a year.

Routinely recommended vaccinations for all travellers include shots against tetanus and diphtheria. The consultation of the mostly adult clients provides further a chance to offer missing vaccinations of the regular schedule of the Swiss recommendations such as vaccinations against hepatitis B, measles, mumps, rubella, varicella, pneumococcal and meningococcal disease and human papilloma virus.
Hepatitis A vaccine is recommended for all travellers visiting countries with poor hygiene standards.
The vaccination which likely prevents most infectious episodes is the one against influenza. There are vaccines available for the Northern and the Southern hemisphere which are given before the respective transmission periods in the winter months of the North (from October to January) and the South (from April to July).

The recommendations for special vaccinations are tailored to the individual needs of the clients. Travel itinerary, travel style and duration are among the criteria to assess potential exposure to pathogens against which vaccinations exist.

Travellers visiting areas where tick-borne encephalitis is prevalent are informed about the respective risks, especially when outdoor activities are envisaged.

Yellow fever vaccinations is mandatory for entering some African and Latin American countries. Other countries with elevated risk, but without compulsory vaccination are included in the recommendations according to the continuously updated epidemiological situation of the disease in endemic areas.
Poliomyelitis booster vaccinations are given to travellers going to areas where the disease is still widely spread or where it has been re-emerging. All vaccinations documents are screened for a complete basic vaccination against this disease that is now virtually unknown in Switzerland, but could be reintroduced if the herd immunity is neglected.
Vaccinations against typhoid fever are cautiously recommended as the risk for the average traveller is low and as the protection level is below 70%. The risk of contracting the disease is highest in South Asian countries or in other endemic countries if travellers are expected to live under very poor hygienic conditions. A new and excellent cholera vaccine is recommended for humanitarian workers under highly difficult hygienic conditions. This vaccine also provides partial protection against coli bacteria, but the calculated rate of protecting against some 10% of those pathogens does not merit the broad use of this vaccine against Escherichia coli infections for cost-effectiveness reasons.
The quadrivalent polysaccharide vaccination against meningococci types A, C, W135 and Y, the most prevalent pathogens found in the meningitis belt of West and Central Africa, is compulsory for visitors of the Hadj. Because of the dramatic course of the disease, the vaccination is also highly recommended for travellers and long-term residents in endemic areas during the transmission periods although very few imported infections are reported in industrialised countries.
Rabies is another rare disease among travellers. No imported case has been recorded in Switzerland over the past 50 years, but some dramatic cases have been reported from France and Germany. Nevertheless, several hundred Swiss travellers are vaccinated every year after a potential rabies exposure after a bite in enzootic countries, requiring passive and active vaccinations in low economy countries with reduced access to those vaccines. Persons embarking for trips to remote enzootic areas and long-term travellers should therefore be offered this vaccine in order to avoid dangerous and frightful experiences and to save the few critical vaccines available in poor countries for their own population. Children, trekkers and persons travelling on two wheels are at a particular risk to be bitten by dogs which are responsible for more than 90% of human rabies worldwide.
The risk of Japanese encephalitis is considered to be very low for travellers, i.e. at 1-2 cases worldwide every year. However, the individual risk can be high as rare cases staying only few days in endemic areas document.
Vaccinations against tuberculosis are not recommended except for newborns before travelling with their parents to high risk settings. As the presently available vaccination is providing virtually no protection against any form of the disease in children and in adults, the potential adverse effects are rendering the BCG vaccine useless or even dangerous in those groups.
Effective vaccinations against tuberculosis, dengue fever, hepatitis C and malaria are only a few among many that would be highly welcome to protect our resident as well as the travelling clients.

Special emphasis is given to counselling immigrant persons and their families as they are at higher risk to contract infectious diseases when they return to their countries of origin, visiting friends and relatives in high risk areas.

Prof. Christoph Hatz

 

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