Factors influencing standard pretravel health advice--a study in Belgium

Travelers with risk factors, medical conditions such as immunosuppression, medication intake, pregnancy, or elderly age, need adaptation or reinforcement of pretravel health advice. The literature provides little data on the frequency of these risk groups in the travel population. This study intended to investigate whether risk factors influencing standard travel advice are common in the population attending our travel clinic.

A prospective survey was carried out over a 2-month period in 2004 at the travel clinic of the Institute for Tropical Medicine in Antwerp, Belgium. A list of risk factors focused on the following three important advice categories: malaria prophylaxis, yellow fever vaccination, and travelers' diarrhea or other enteric infections. We counted how frequently a risk factor was observed for each advice category (potential influence) and, after considering the travel characteristics, how often a real adaptation of advice was necessary (actual influence).

Of 2,227 travelers, 276 were found to have a possible influencing factor (12.4%). The potential influence was 10.9% (243/2,227) for malaria prophylaxis advice, 6.1% (136/2,227) for yellow fever vaccination, and 1.9% (43/2,227) for travelers' diarrhea advice. The actual influence was lower 8% (184/2,227), 5% (109/2,227), and 1.2% (27/2,227), respectively. The main interfering factors were as follows: for influence on malaria advice, age>or=60 years (44%) and neuropsychiatric disorders (15.6%); for yellow fever vaccination, age>or=60 years (63.2%) and immunosuppression (10.3%); and for influence on travelers' diarrhea advice, decreased gastric acidity (44.2%) and immunosuppression (32.6%).

Travelers with risk factors are not infrequently seen at our travel clinic. Some groups are more prominently present and could be the focus of travel group-specific instructions. The study suggests that being informed about risk groups is essential for advising travelers.