Preterm infants are at increased risk of developing infections early in life due to a less mature immune system compared to full-term infants. Moreover, protection by the placental transfer of maternal antibodies in general and specifically against vaccine antigens has shown to be significantly lower in very preterm infants (gestational age (GA)< 32 weeks) compared to term infants. In this study we aim to investigate the immune system development of very preterm infants. Adequate immune response to vaccination is considered both clinically important as well as a functional test of the immune system. However, data on the antibody and Ag-specific memory B cell response to vaccination in preterm infants are limited.~Primary objective is to study the antibody immune response to routine vaccinations in very preterm infants (GA<32 weeks). Secondary aim is to study the immune system more extensively using flow cytometry, ELISA and single cell transcriptomics to measure development of Ag-specific memory B cells raised in response to vaccination, and by using proteomics, epigenetics, and microbiome studies.
In this study the response to vaccination and development of the immune system in very preterm infants upon the current vaccination schedule will be compared to healthy term infants.