A new study looked at the coronavirus variant Omicron in mice and Syrian hamsters and found that lung infections, clinical illness, and pathology with B.1.1.529 were milder compared to other SARS-CoV-2 variants. The results were published na revista Research Square.
A team of American and Japanese researchers evaluated micron and other variants — with different combinations of mutations — in 129 mice, in three laboratories in the Consortium of the Evaluation of Viral Evolution (SAVE) of the National Institute of Allergy and Infectious Diseases.
The research used microcomputed tomography to check lung abnormalities in animals infected with Delta strain (B.1.617.2), initially identified in India and that left the world on alert due to its high rate of transmission, and compared with mice infected by Ômicron.
The images revealed that Syrian hamsters infected with Delta had a more severe disease picture (with pulmonary sequelae and severe disease), while those infected with Ômicron had a substantially lower disease score.
The results also showed that strains that had the N501Y mutation, such as the D614G strain — the first variant of Covid-19 — or Beta (B.1.351), made about 10 to 15% of mice lose weight
In contrast, with Ômicron infection, none of the 129 animals lost weight.
The scientists also assessed the viral load of Syrian hamsters infected with Ômicron and other variants.
They wrote that “Mice infected with WA1/2020 N501Y / D614G or Beta sustained high levels of infection in the nasal wash, nasal concha and lung. And that means, that level of infection was previously associated with evidence of mild pneumonia.
Still, the research says that “the most severe Ômicron infections and illnesses were seen in mice that express hACE2 — a protein that helps the coronavirus to enter cells—which is consistent with the results of other strains and variants of SARS-CoV-2,” they wrote.
The researchers emphasize that more research is underway to determine the basis of attenuation in mice and Syrian hamsters and to determine how it relates to the patterns of Ômicron B.1.1,529 infection observed in humans.
Furthermore, they believe the discovery could pave the way for further studies on vaccines against Ômicron.
Reference: CNN Brasil
