A 90-year-old Belgian woman who died from COVID-19 in March had contracted two variants of coronavirus at the same time, which is believed to be the first documented case of its kind, a scientific congress and Belgian media said on Sunday.

The case, discussed at this year's European Congress on Clinical Microbiology & Infectious Diseases (ECCMID), shows that it is possible to catch two COVID-19 variants simultaneously, the society that organized the congress said in a statement.

The society said the woman became sick with Alpha and Beta types first identified in Britain and South Africa and her doctors said she could have contracted the infections from two different people.

The woman, who was treated at a hospital in Aalst near Brussels, had not been vaccinated, Belgium's Dutch-language public broadcaster VRT said.