A growing body of evidence suggests that the Omicron Covid variant is more likely to infect the throat rather than the lungs, which may explain why it appears to be more infectious but less lethal than other versions of the virus.

Six studies, four of which were published since Christmas Eve, have found that Omicron does not harm people's lungs as much as Delta and other previous Covid variants. Other scientists have not yet reviewed the studies.

On his account, Professor of virology at University College London Deenan Pillay said: “The result of all the mutations that make Omicron different from previous variants is that it may have altered its ability to infect different sorts of cells.” 

“In essence, it looks to be more able to infect the upper respiratory tract cells in the throat. So it would multiply in cells there more readily than in cells deep in the lung. This is really preliminary but the studies point in the same direction.”

According to Prof. James Stewart, researchers from the University of Liverpool's Molecular Virology Research Group published a pre-print on Boxing Day showing that Omicron causes "less severe disease" in mice. According to the study, mice infected with Omicron lose less weight, have lower viral loads and have less severe pneumonia.

“The early indications are that it's good news, but that’s not a signal to drop our guard, because if you’re clinically vulnerable, the consequences are still not great – there are deaths from Omicron. Not everyone can rip their masks off and party.”

The most recent scientific research comes amid a debate over the best way to conduct home testing.

Although the tests were continuously monitored by researchers, the UK Health Security Agency stated that there was no evidence that rapid tests differed in their ability to detect the Omicron or Delta variants.