Omicron is less severe than the previous Covid-19 variants because it does not cause as much damage in the lungs, a spate of studies have suggested.
A study by a consortium of US and Japanese scientists on hamsters and mice found those infected with Omicron had less lung damage, lost less weight and were less likely to die than those who had other variants, the Daily Mail reported.
It found mice infected with Omicron had a tenth less of the virus in their lungs compared to those with other variants, the report said.
The findings backed up another paper by researchers at the University of Hong Kong, who studied human tissue in Omicron victims.
They found Omicron grew significantly more slowly in 12 lung samples than earlier strains of the virus, the report said.
Experts believe the fact the super mutant variant tends not to replicate as much in the lower parts of the lungs means it causes less significant damage, which could be behind its reduced severity, the Daily Mail reported.
Data from South Africa showed Omicron sufferers are up to 80 per cent less likely to end up in hospital than those with Delta. And a similar study by the UK Health and Security estimated the risk was 70 per cent less.
Roland Eils, a computational biologist at the Berlin Institute of Health, said there is an emerging theme in the literature suggesting the variant tends to stay outside the lungs.