Inclusion criteria | Exclusion criteria | |
---|---|---|
Parents | All mother–child pairs that live in a proximity to Utrecht | Acquired or innate immune deficiencies |
Parents currently breastfeeding and intending to continue breastfeeding until at least 3 months postpartum | Insufficient control of the Dutch language | |
Infant | Severe cardiac or pulmonary disorders or other severe organ diseases | |
Severe prematurity defined as GA < 32 weeks |