Estimation of Benzathine Penicillin G Demand for Congenital Syphilis Elimination with Adoption of Dual HIV/Syphilis Rapid Diagnostic Tests in Eleven High Burden Countries

Abstract

Background: WHO recommends use of rapid dual HIV/syphilis tests for screening pregnant women (PW) during antenatal care to prevent mother-to-child transmission. Scale up of these tests implies a need to accurately forecast and procure benzathine penicillin (BPG) to treat the additionally identified PW with syphilis. Methods: Country-reported antenatal syphilis screening and treatment coverage values in 2019 were scaled up linearly to 95% coverage by 2030 for 11 focus countries. Antenatal syphilis screening coverage was substituted with HIV screening coverage to estimate potential contribution of rapid dual HIV/syphilis tests in identifying additional PW with syphilis. BPG demand was calculated for 2019 through 2030 accordingly. Results: The estimated demand for BPG (in 2.4 million unit vials) using current maternal syphilis prevalence and treatment coverage will increase from a baseline of 414,459 doses in 2019 to 683,067 doses (+65%) in 2021 assuming immediate replacement of single HIV test kits with rapid dual HIV/syphilis tests for these 11 countries. Continued scale up of both syphilis screening and treatment coverage to reach elimination coverage of 95% will result in an estimated demand increase of 160%, (663,969 doses) from 2019 baseline for a total demand of 1,078,428 BPG doses by 2030. Conclusions: Demand for BPG will increase following adoption of rapid dual HIV/syphilis test kits due to increases in maternal diagnoses of syphilis. To eliminate congenital syphilis, country programs will need to synergize with disease surveillance programs to accurately forecast BPG demand with scale up of antenatal syphilis screening to ensure adequate treatment is available for pregnant women diagnosed with syphilis. Funding: This study was made possible by support from the Bill & Melinda Gates Foundation, the Clinton Health Access Initiative, the U.S. Centers for Disease Control and Prevention, Atlanta, USA and the World Health Organization, Geneva, Switzerland Declaration of Interest: None to declare.