Risk factors for syphilis infection in the South Backa blood donor population

Syphilis is one of infectious diseases that can be transmitted by blood transfusion. Determining the frequency of syphilis among blood donors and the relevant risk factors is an important aspect of safe blood transfusion. To determine the frequency and the trend of syphilis infection among blood donors in South Backa Region, to classify the confirmed infection and to describe demographic characteristics of seropositive blood donors and their risk factors. This retrospective study analyzed results of routine EIA syphilis screening and blood donor data from South Backa Region between 2004 and 2008. Thirteen out of 153,431 tested blood units were confirmed as syphilis-infected.The study found that the overall frequency of infection was 8.47 per 100,000 blood donations, with a trend increase of 2.4%; there was a statistically significant (p < 0.001) higher frequency among first-time blood donors (51.93/100,000) than regular ones (2.84/100 000). The highest prevalence was noted in donors aged over 45 years. All cases were classified as past syphilis infections. Post-donation interviews revealed exposure risk in 69.23% of the donors. A higher frequency of past infections detected in older donors is probably due to a higher prevalence and incidence of syphilis in the past. Further continual epidemiologic follow-up of syphilis in blood donors is crucial in obtaining safe blood.