The case of a newborn with antibodies to SARS-CoV-2 but no disease has added to debate over how the virus or antibodies are transferred during pregnancy, and if the latter confers protection.

Singaporean doctors are investigating the case and the wider issue in an ongoing study in the city-state’s public hospitals.

The WHO says while some pregnant women have an increased risk of developing severe COVID-19, it is not yet known whether an infected pregnant woman can pass the virus to her fetus or baby during pregnancy or delivery.

The Singaporean case was reported in the local newspaper the Straits Times. The mother said she was infected with coronavirus in March when she was pregnant and that doctors had told her her infant son had antibodies against the virus, but was born without the infection.