Syphilis incidence during the COVID-19 pandemic: systematic review and meta-analysis

The COVID-19 pandemic created a public health crisis that affected mental and physical health. Research examined its effect on sexually transmitted infections, particularly syphilis. Asymptomatic stages and inadequate screening likely delayed detection and increased transmission after restrictions eased. Limited health care access and lockdowns reduced social interactions. Studying syphilis reveals how changes in health care access influenced transmission, showcasing the pandemic as a natural experiment for sexually transmitted infection epidemiology. We used the PubMed database, selecting studies from 2019 to August 2024. The meta-analysis evaluated incidence rate ratios from 2019 to 2020 to assess the pandemic's global impact on syphilis rates. Published papers were categorized by region for subgroup analysis. Of the 233 studies, 21 were selected for further analysis. A common-effects model was used to calculate the incidence rate ratio with a 95% CI. We assessed publication bias using funnel plot asymmetry and Egger test, examining heterogeneity with the I² statistic. We found a 14% decrease in syphilis incidence in various regions (incidence rate ratio: 1.14; 95% CI: 1.06-1.24, P = .006). Analysis by country and city was inconclusive. This indicates that the impact of the epidemic on syphilis transmission and diagnosis may be multifactorial. Syphilis incidence fell during the pandemic, illustrating that reduced health care access and social restrictions affected transmission. National analyses were inconclusive, suggesting the pandemic's effects on syphilis may vary by location. These findings emphasize the need for further research on the pandemic's long-term impact on syphilis trends and the importance of improving sexually transmitted infection surveillance and health care access during recovery.