Antitetanus toxoid antibodies in mothers and neonates: a single-centre study from Uganda

Abstract

Background: Neonatal mortality due to tetanus persists in Uganda despite the mandatory vaccination of pregnant mothers. Maternal antibodies wane within a year. Uganda's maternal vaccination guidelines do not specify the timing or frequency of tetanus shots, contributing to suboptimal transfer of tetanus antibodies to neonates. We aimed to determine the prevalence and factors associated with protective tetanus antibodies among newborns at Kawempe National Referral Hospital.

Methods: We conducted a cross-sectional study among 293 mother-newborn pairs. At delivery, neonatal cord and maternal venous blood were collected and titred for antitetanus antibodies using a quantitative ELISA kit. The primary outcome of the study was the proportion of newborn babies with tetanus antibodies ≥0.1 IU/mL. Associated factors were determined using generalised linear models for the Poisson family with a log link and robust variance estimation.

Results: A total of 258/293 (88.1%) newborns had protective antibody titres. Factors associated with adequate protective antibodies in the newborn included: high (≥0.1 IU/mL) maternal antibody titres, first antenatal visit ≥12 weeks of gestation and receiving a tetanus toxoid (TT) shot ≥28 weeks of gestation. However, number of doses received before current pregnancy was not associated with adequate protective antibody titres.

Conclusion: There is a high prevalence of adequate protective levels of antibodies among TT-vaccinated mothers. Maternal titres and a third trimester TT dose correlate with adequate levels of protective anti-TT antibodies among newborns. A third trimester TT dose is recommended.

Keywords: epidemiology; health services research; microbiology; neonatology.