Prevalence of syphilis and associated factors in homeless people of Sao Paulo, Brazil, using a Rapid Test.

Introduction: Homeless people are a vulnerable group to sexually transmitted diseases (STD) with high prevalence of syphilis and hepatitis.

Objectives: To estimate the prevalence of syphilis infection and its association with risky behaviors for STDs in a sample of homeless people, and to assess the feasibility of the use of rapid syphilis test (RST) in this population.

Methods: Cross-sectional study, in a convenience sample of homeless people assisted in social support services of São Paulo, between 2006 and 2007. A structured questionnaire was applied and RST was performed. In addition, a blood sample for syphilis detection was also collected. The sensitivity and specificity of the RST was estimated using conventional laboratory diagnosis (VDRL + TPHA) as reference.

Results: 1,405 volunteers were included in the study. The prevalence rate of syphilis was 7.0%, and was associated with homosexual practices (OR(adj) 4.9; 95%CI 2.6 - 9.4), prior history of STD (OR(adj) 2.6; 95%CI 1.7 - 4.0) and with self-referred non-white race (OR(adj) 1.9; 95%CI 1.1 - 3.4). The sensitivity and specificity of the RST for syphilis were, respectively, 81.4 and 92.1%.

Conclusion: The high prevalence of syphilis infection among homeless people shows the need for actions for its control and the utilization of RST that can be considered an efficient strategy due to its sensitivity and specificity. Public Health policymakers must strengthen actions for syphilis control, with screening tests for syphilis and early treatment, decreasing morbidity with the improvement of sexual and reproductive health of the population in general and especially the most vulnerable.