A woman gave birth to a baby with coronavirus antibodies.
The Singaporean mum, who was infected with the coronavirus in March when she was pregnant, delivered a child who did not have Covid-19.
The baby did have coronavirus antibodies however, giving them protection against the deadly disease, the Straits Times newspaper reported on Sunday.
"My doctor suspects I have transferred my Covid-19 antibodies to him during my pregnancy," mum Celine Ng-Chan told the paper.
Ng-Chan had been mildly ill from the disease and was discharged from hospital after two-and-a-half weeks.
The World Health Organisation says it is not yet known whether a pregnant woman with Covid-19 can pass the virus to her foetus or baby during pregnancy or delivery.
To date, the active virus has not been found in samples of fluid around the baby in the womb or in breast milk.
Doctors in China have reported the detection and decline over time of Covid-19 antibodies in babies born to women with the coronavirus disease, according to an article published in October in the journal Emerging Infectious Diseases.
Transmission of the new coronavirus from mothers to newborns is rare, doctors from New York-Presbyterian/Columbia University Irving Medical Center reported in October in JAMA Pediatrics.
The question of when people do and don't get antibodies has continued to throw up some surprising answers.
Earlie this month three children in one family in Australia were found to have developed Covid antibodies, despite testing negative for the coronavirus.
Researchers from the Murdoch Children’s Research Institute have detailed the unusual case in a new report.
The parents had tested positive and were showing symptoms for coronavirus, after attending an interstate wedding without their children.
Despite being in close contact with their infected parents, none of the three children tested positive for the virus.
However, antibody tests revealed that all family members had antibodies in their saliva.
Dr Melanie Neeland, who led the laboratory-based aspect of the report, said: "The youngest child, who showed no symptoms at all, had the strongest antibody response.
“Despite the active immune cell response in all children, levels of cytokines, molecular messengers in the blood that can trigger an inflammatory reaction, remained low. This was consistent with their mild or no symptoms.”
