Congenital Syphilis in Honiara, Solomon Islands

Congenital syphilis remains a significant cause of newborn mortality and long-term neurodevelopmental problems in some low- and middle-income countries. This study was done in Honiara, Solomon Islands to determine the incidence of babies born to mothers with a positive venereal disease research laboratory (VDRL) test and a positive Treponema pallidum haemagglutination assay (TPHA); to determine the VDRL status of newborns and features of congenital syphilis; and to estimate the proportion of stillbirths associated with syphilis.

All neonates born to VDRL-positive mothers, including stillbirths were included between April and July 2019. Neonates were examined, investigated and treated.

Among 1534 consecutive births, 1469 were live births and 65 (4.2%) were stillbirths. One hundred and forty-three neonates were born to VDRL-positive mothers: 130 (90.1%) were live infants and 13 (8.9%) stillbirths. Of the 130 VDRL-exposed live-born infants, 72 (55%) had reactive VDRL and a positive TPHA and 7 (9.7%) had clinical signs of congenital syphilis. Five of the infants with clinical signs of syphilis infection had a 4-fold higher VDRL titre than their mother. Four infants of VDRL-positive mothers died during admission, all of whom had clinical signs of syphilis. Ninety percent of affected infants were born to mothers who were not treated or only partially treated during pregnancy.

In this study, 1:210 live-born babies had clinical and serological evidence of congenital syphilis, and evidence of Treponema infection was found disproportionately in stillbirths. In a setting where Treponema infections are common, an empirical approach to prevention may be needed.