Background: To reduce the risk of pertussis-related morbidity and mortality in early life, an increasing number of countries recommend maternal pertussis vaccination. However, there is limited knowledge about half-lives of vaccine-induced pertussis-specific maternal antibodies, especially in preterm infants, and factors potentially influencing them.
Methods: We compared 2 different approaches to provide estimates of the half-lives of pertussis-specific maternal antibodies in infants and explored potential effects on the half-life in 2 studies. In the first approach, we estimated the half-lives per child and used these estimates as responses in linear models. In the second approach, we used linear mixed effect models on a log2 transformed scale of the longitudinal data to use the inverse of the time parameter as an estimate for the half-lives.
Results: Both approaches provided similar results. The identified covariates partly explain differences in half-life estimates. The strongest evidence we observed was a difference between term and preterm infants, with the preterm infants showing a longer half-life. Among others, a longer interval between vaccination and delivery increases the half-life.
Conclusions: Several variables influence the decay speed of maternal antibodies. Both approaches have advantages and disadvantages, while the choice is secondary when assessing the half-life of pertussis-specific antibodies.
Clinical trials registration: NCT02408926 and NCT02511327.
Keywords: Tdap; antibody kinetic; half-life estimation; maternal antibodies; pertussis; vaccination in pregnancy.
© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.