Changing Epidemiology of Sexually Transmitted Infections: Call for New Strategies Against the Increase in Chlamydia Infection in Sweden

Abstract

This descriptive analysis of sexually transmitted infections (STIs) is based on data regulated by the Swedish Communicable Disease Act and consists of free testing and treatment, partner tracing and notification. Today, chlamydia is the only STI that affects the general population in Sweden. In the past gonorrhoea and syphilis had an appreciable effect on the general population. However, in the 1990s both of these diseases became rare. HIV has almost exclusively been restricted to three subpopulations (men who have sex with men, injecting drug users and people from HIV endemic countries). The Swedish strategy employed to reduce gonorrhoea and syphilis has been highly successful as demonstrated by a substantial decrease in the incidence of gonorrhoea and syphilis in the mid-1990s. A recent slight increase in syphilis and HIV might be due to the introduction of highly active antiviral therapy (HAART) that may have promoted promiscuous behaviour. The present chlamydia strategy, which focuses on opportunistic screening, partner tracing and condom use, has failed despite being one of the world's most all comprehensive plans. The number of chlamydia cases more than doubled after 1998, and in 2007, the number was the highest ever recorded in Sweden. This noticeable increase in chlamydia cases has important implications and suggests that greater attention should be given to transmission dynamics, including the effects of screening programmes and acquired immunity. Complication and clearance rates after asymptomatic chlamydia infection need to be established, but the most important goal is to encourage behavioural changes in terms of fewer episodes of unprotected sexual intercourse and fewer sexual partners.