Explained: Why Omicron is less severe?

New Delhi, Jan 03: Though dubbed mild, the sudden surge in Omicron variant of the coronavirus has become a major source of concern. Scientists and medical experts are keeping a close track of the variant and any related developments.

A recent study on lab animals and human tissues is providing evidences of why the highly infectious Omicron variant showing mild symptoms than previous Covid-variants.

Studies on mice and hamsters have found that Omicron produced less damaging infections to the lungs, and instead was limited largely to the nose, throat, and windpipe, according to The New York Times.

"It is 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 was quoted as saying.

Similar views were expressed by experts at Hong Kong University, which said the omicron variant infects around 70 times faster than delta and the original Covid-19 strain, though the severity of illness is likely to be much lower.

The study, conducted by a team of researchers led by Michael Chan Chi-wai, found that the newest variant of concern replicated less efficiently -- more than 10 times lower -- in the human lung tissue than the original strain which may signal "lower severity of disease."

The study, which suggests that omicron jumps faster from one person to another but doesn't damage lung tissues as much as its predecessor strains did, is yet-to-be-published.

A study conducted by South Africa also showed Omicron variant of the COVID-19 appears to be having a less severe impact than the earlier variants.

However, World Health Organisation is worried about the omicron and delta variants of COVID-19 combining to produce a "tsunami" of cases.

"I'm highly concerned that omicron, being more transmissible (and) circulating at the same time as delta, is leading to a tsunami of cases," Tedros Adhanom Ghebreyesus said at an online news conference.

That, he said, will put "immense pressure on exhausted health workers and health systems of the brink of collapse." WHO said in its weekly epidemiological report that the "overall risk" related to omicron "remains very high."

It cited "consistent evidence" that it has a growth advantage over the delta variant. It noted that a decline in case incidence has been seen in South Africa, and that early data from that country, the U.K. and Denmark suggest a reduced risk of hospitalization with omicron, but said that more data is needed.