Decreased Passive Immunity to Respiratory Viruses through Human Milk during the COVID-19 Pandemic
Marloes Grobben, Hannah G. Juncker, Karlijn van der Straten, A. H. Ayesha Lavell, Michiel Schinkel, David T. P. Buis, Maarten F. Wilbrink, Khadija Tejjani, Mathieu Claireaux, Aafke Aartse, Christianne J.M. de Groot, Dasja Pajkrt, Marije K. Bomers, Jonne J. Sikkens, Marit J. van Gils, Johannes B. van Goudoever, Britt J. van Keulen
Abstract
Passive immunity derived from antibodies in human milk is important for protecting young infants against invading viruses. During the COVID-19 pandemic, circulation of common respiratory viruses was virtually absent due to preventative measures. In this study, we observed a decrease in human milk antibody levels against common respiratory viruses several months into the COVID-19 pandemic. This waning of antibody levels might partially explain the previously observed surge of hospitalizations of infants, mostly due to RSV, when preventative hygiene measures were lifted. Knowledge of the association between preventative measures, antibody levels in human milk and subsequent passive immunity in infants might help predict infant hospital admissions and thereby enables anticipation to prevent capacity issues. Additionally, it is important in the consideration for strategies for future lockdowns to best prevent possible consequences for vulnerable infants.