To investigate the antibody based immune response (ELISA RBD antibodies (IgG) ) on day 28 after the second vaccination in pregnant women, age matched control non-pregnant women and postpartum lactating women. The definition of response will be based on a serological correlate of protection for COVID-19 based on SARS-CoV-2 spike(S)-protein specific serum IgG antibody levels (in IU/mL or seroconversion (a≥4-fold increase of the geometric mean concentration (GMC) of anti-S protein IgG antibodies over baseline)). For those with a previous COVID infection, the in house multiplex assay from Sciensano will be performed to discriminate between previous infection and vaccination

To investigate the antibody based immune response (ELISA RBD antibodies (IgG) ) on day 28 after the second vaccination in pregnant women, age matched control non-pregnant women and postpartum lactating women. The definition of response will be based on a serological correlate of protection for COVID-19 based on SARS-CoV-2 spike(S)-protein specific serum IgG antibody levels (in IU/mL or seroconversion (a≥4-fold increase of the geometric mean concentration (GMC) of anti-S protein IgG antibodies over baseline)). For those with a previous COVID infection, the in house multiplex assay from Sciensano will be performed to discriminate between previous infection and vaccination