Omicron: Emergence of variant causing less severe infections could mark the end of pandemic, say scientists

"We're now in a totally different phase," said Monica Gandhi, an immunologist at the University of California, San Francisco, according to the report.

"The virus is always going to be with us, but my hope is this variant causes so much immunity that it will quell the pandemic."

The Omicron variant was first detected in South Africa just more than a month ago, and scientists in the country had cautioned to wait and watch till enough data could be gathered to analyze how the new variant affected the people.

But data from the past week suggest that a combination of widespread immunity and numerous mutations have resulted in a virus that causes far less severe disease than previous iterations.

A study on patients hospitalized in South Africa has revealed that they were 73 percent less likely to develop severe disease than patients admitted during the delta-dominated third wave, the report said.

"The data is quite solid now that hospitalizations and cases are decoupled," said Wendy Burgers, an immunologist at the University of Cape Town.

Earlier, much of the alarm over Omicron was raised due to the variant's large number of mutations, many of which are on the spike protein, the part of the virus responsible for helping it invade host cells.

Those mutations not only allowed the virus to easily infect the unvaccinated but also evade antibody responses from both previous infections and vaccines.

The virus' ability to infect the lungs is one of the factors that decide the severity of infection. While a mild infection starts from the nose and travels down the throat but remains confined to the upper respiratory tract, a severe infection travels further to the lungs, that's usually when more severe symptoms occur.

But five separate studies in the past week suggested that the variant does not infect the lungs as easily as previous variants.

Bloomberg reported that five separate studies in the past week suggested that the variant does not infect the lungs as easily as previous variants.

In one study, released as an online pre-print by a large consortium of Japanese and American scientists, hamsters and mice infected with omicron experienced far less lung damage and were less likely to die than those infected with previous variants.

Another study out of Belgium found similar outcomes in Syrian hamsters, which have been known to experience particularly severe illness with previous iterations of the virus.

In Hong Kong, scientists studied a small number of lung tissue samples from patients collected during surgery and found that omicron grew more slowly in those samples than other variants did.

Burger said this change has to do with the change in the virus' anatomy.

"It used to use two different pathways to get into cells, and now because of all the changes to the spike protein, it's preferring one of those pathways," she said. "It seems to prefer to infect the upper respiratory tract rather than the lungs."

 This means less severe infection, but also more transmissibility as the virus replicates more often in the upper respiratory tract, from which it can more easily spread, Burgers underscored.

While Omicron is good at penetrating the first line of defence posed by the antibodies, they are less capable of avoiding the second-line defences of vaccines and prior infections: T-cells and B-cells.

T-cells are making the second line of defence or attacking a virus once it makes its way into the body's cells if antibodies fail to prevent infection in the first place.

A study on Covid patients showed that about 70-80% of the T-cell response is preserved compared with previous strains of the virus.  This means that those who are vaccinated or had an infection in the past six months, their T-cells can Omicron and fight it off relatively quickly.

This latest research will need to be followed up with further study, the report said.

If the findings hold up to additional scrutiny, it just might explain why current infections appear to be more mild than in previous waves of the virus.

"When you start to see different kinds of data all pointing in the same direction, you begin to feel more confident that it's going to hold up," said Jessica Justman, a Columbia University Medical Center epidemiologist, stated the Bloomberg report.

Despite this, the hospializations and deaths will rise still rise though the numbers would tick up slower than before.

"When your denominator is very large because many, many people are getting infected, you still wind up having many people going to the hospital who need care," Justman said.

Higher case numbers will also still create disruption in work, travel and schooling as authorities take measures to curb the spread.

Gandhi, at University of California, San Francisco, said that while case numbers might be reaching records, she hopes omicron's combination of high transmissibility and mild infection might signal the beginning of the end, the Bloomberg report stated.

However, vaccinated patients infected with Omicron developed strong immune responses against other versions of the virus as well, she said, referring to a study in Hong Kong.

"I hope this variant creates profound immunity in the population," she said, according to the report. "It will hopefully end the pandemic," she added.