Studies suggest Omicron variant of Covid-19 Is less severe than Delta
The omicron variant causes milder disease than previous versions of the coronavirus, according to a spate of new studies on lab animals and human tissues.
In studies on mice and hamsters, omicron produced less-damaging infections, often limited largely to the upper airway: the nose, throat and windpipe.
The variant did much less harm to the lungs, where previous variants would often cause scarring and serious breathing difficulty.
“It’s fair to say that the idea of a disease that manifests itself primarily in the upper respiratory system is emerging,” Roland Eils, a computational biologist at the Berlin Institute of Health who has studied how coronaviruses infect the airway, , told the New York Times.
In November, when the first report on the omicron variant came out of South Africa, scientists could only guess at how it might behave differently from earlier forms of the virus. All they knew was that it had a distinctive and alarming combination of more than 50 genetic mutations.
Previous research had shown that some of these mutations enabled coronaviruses to grab onto cells more tightly. Others allowed the virus to evade antibodies, which serve as an early line of defense against infection. But how the new variant might behave inside of the body was a mystery.
On Wednesday, a large consortium of Japanese and American scientists released a report on hamsters and mice that had been infected with either omicron or one of several earlier variants. Those infected with omicron had less lung damage, lost less weight and were less likely to die, the study found.