A woman who recently died from Covid-19 was recently found to have been infected with two separate strains - at the same time.
Doctors revealed that the 90-year-old was diagnosed with both the British Kent and South African variants, in a case believed to be the first of its kind. Unfortunately, the woman died within five days of her symptoms worsening.
The discovery has implications for how the viruses interact in an infected person, with it worried the alarming phenomenon could generate deadlier variants that dodge vaccines and spread more easily.
Dr Anne Vankeerberghen, a molecular biologist at OLV Hospital in Aalst, Belgium, where the incident occurred, said: "Both these variants were circulating in Belgium at the time.
"So it is likely the lady was co-infected with different viruses from two different people. Unfortunately, we don't know how she became infected."
The 90-year-old was admitted on 3 March - and tested positive that day. She lived alone and received nursing care at home. She had no major underlying health problems - and had not been vaccinated.
A throat swab showed she had caught the 'Kent strain' first found in south east England - and another first detected in South Africa.
Initially, the patient was breathing well and had no signs of respiratory distress. But she declined quickly - and died five days later.
Dr Vankeerberghen said: "This is one of the first documented cases of co-infection with two SARS-CoV-2 variants of concern."
Their presence was confirmed by PCR (polymerase chain reaction) testing on a second respiratory sample through genome sequencing.
All viruses, including SARS-CoV-2 that causes Covid, mutate.
In the pandemic different types are split into two groups - VOCs (variants of concern) and VOIs (variants of interest).
It has helped the World Health Organisation (WHO) prioritise monitoring and research.
