Differences in travel-related incidence of chlamydia by age groups, gender and destination: Sweden 2000-2013

Background: The absolute number of travel-related Chlamydia cases in Sweden has consistently increased between 2000 and 2013. Given the growth in international travel, we aimed to study the trends of travel-related Chlamydia incidence to determine differences and identify high-risk groups and destinations. Methods: For 2000-2013 we calculated annual Chlamydia incidence per 100,000 travels by dividing the number of notified travel-related cases by the number of travels; the latter were collected from a yearly survey among Swedish residents. For specific destinations 95% confidence intervals were calculated and monotonic yearly trends tested. Results: The overall median annual travel-related Chlamydia incidence was higher for women than for men, but the opposite was true in age groups > 25 years. For men, Thailand had the highest incidence, which was 3-7 times higher than the next highest destination in each age group. Spain, Turkey and Thailand had the highest incidence among women, but differences between countries were smaller than for men. For most destinations the yearly trends were stable. Conclusions: We showed different profiles for men and women and age groups in terms of high incidence destinations. This specific information could allow to better tailor safe sex messages and advocate post-travel Chlamydia testing to target groups travelling to certain destinations.