This is a study prospective cohort study at an urban academic centre, with two parts:

1. Health outcomes, and maternally transferred antibodies, in babies born to mothers who had antenatal COVID-19 and convalesced before delivery, followed up until 12 months of age
2. Safety and protective properties of breast milk after lactating women are vaccinated against COVID-19

This proposal aims to provide a multi-faceted approach to study how immunity may be transferred - both transplacentally and through breastfeeding, from mother to child, in the context of COVID-19.

We first recruit all babies delivered to mothers convalescent from antenatal COVID-19, to 1) follow up their growth and development, and 2) study the protective effects of antibodies transferred from mother to child transplacentally during pregnancy, as well as postnatally through breastfeeding. We compare these to a cohort of healthy controls whose mothers did not have COVID-19 during pregnancy.

Next, we compare the protective effects of antibodies transferred during breastfeeding from mother to child after lactating mothers are vaccinated against COVID-19, to that of natural infection. We also study the safety of breastfeeding after vaccination by looking for vaccine components in the breast milk.

Inclusion Criteria:

Lives in Singapore

Exclusion Criteria:

Prematurity Congenital abnormalities Primary immunodeficiencies Autoimmune disorders

For group 3; only lactating women recruited

Part 1 of study - infants Part 2 of study - lactating women