(P409) Differences in syphilis positivity according to geographic areas of south Brazil

Background: Syphilis has recently resurfaced as a significant public health problem with increasing rates since the 2000s in different countries. Brazil has experienced a progressive increment in both congenital and acquired syphilis. So, we aimed to evaluate differences in positivity between the capital and adjacent cities of the southernmost state of Brazil.

Methods: A questionnaire with social, demographic, and sexual behavior was applied to volunteers in a mobile research unit. All participants did syphilis rapid and confirmatory test, between August 2021-2022. We used Fisher's Chi-Square and Mann-Whitney test to compare variables at a significance level of 0.05, using R 4.1.3.

Results: Of the 3582 participants enrolled, 2842 were from Porto Alegre, the capital State (79.34%) and 740 were from the metropolitan region (20.66%). Participants from the capital were slightly older (42.0±16) than from other cities (40.5 years±15.1; p=0.04) and more educated (31.23% vs. 23.38%; p< 0.001). There were no differences regarding race/skin color, employment situation and marital status.
Regarding family income, the capital city has a higher proportion of people in the category with low than 252.00 dollars per month (17.49% vs. 12.53%) and higher than 1,260.00 dollars per month (8.17% vs. 4.87%; p< 0.001) than other cities.
Overall, there was no difference in the percentage of positivity of syphilis rapid tests (16.16%) in the capital and metropolitan region (17.3%) or confirmatory test (9.89% and 10.96%, respectively; p=0.49)
However, when we analyzed age subgroups, a confirmatory test positivity was higher in volunteers over 60 years in the capital (14.0% vs. 7.2% %) and higher in the groups less than 30 years in the metropolitan region (8.6% vs.11.7%; p=0.028).
The absence of risk perception was higher in people more than 60 years and those with less education.

Conclusion:
Syphilis is a critical problem in public health, affecting the capital and adjacent cities. The magnitude of syphilis in older ages associated with the lower perception of risk contributes to the maintenance of the epidemic. Therefore, specific preventive and diagnostic strategies are needed for different age ranges to eradicates this disease.