Point-of-care diagnosis of active syphilis for the elimination of congenital syphilis

Burnet Institute
Organization Location: 
Melbourne, Australia

Annually, syphilis contributes to more than half a million adverse pregnancy outcomes affecting both mothers and newborns. Congenital syphilis affects more newborns than any other infection (including HIV or tetanus) with many infants dying within the first year of life, and its elimination has recently become a global priority. Treatment of syphilis is simple and inexpensive, but diagnosis of active syphilis is challenging, requiring venous blood collection, laboratory equipment and trained staff, which hampers implementation and thus delivery of these potentially life-saving treatments. Rapid point-of-care diagnostic tests can increase uptake by facilitating same-day treatment of pregnant women to treat maternal disease and prevent stillbirth and congenital syphilis. However, existing point-of-care tests cannot differentiate between active syphilis and past or treated syphilis, limiting their impact particularly in high-prevalence settings. We propose to optimize and pilot-test a finger-stick based rapid syphilis point-of-care test, featuring a novel IgM antibody test (developed by Burnet Institute) that offers specificity for active infection, in combination with a total antibody test (developed by Omega Diagnostics) that offers optimal sensitivity, in one single test-strip. This test will be optimized against “gold standard” reference tests, using approximately 60 plasma samples representing active syphilis, past syphilis and healthy controls (ICRHK, Kenya). Test performance will be validated in a “blinded” beta-testing study using an independent panel of plasma samples (n=300, NCSTDs, China). The results will allow us to estimate the potential impact of the test in reducing congenital syphilis, providing the basis for future implementation studies.

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