Understand why a highly transmissible Omicron variant does not harm the lungs

New Delhi: As India braces for the peak of the third Covid wave, with Omicron displacing all other existing variants, scientists are scrambling to figure out how this heavily mutated virus spreads so quickly and affects people at an alarmingly high rate while avoiding the lungs, which have been the key organs affected by the Covid-19 respiratory disease.

According to researchers at the University of Hong Kong, the Omicron variant multiplies about 70 times faster inside human respiratory tract tissue than the Delta variant.

When compared to Delta, Omicron reaches higher levels in the tissue 48 hours after infection.

“The discovery suggests that mutations in Omicron have accelerated the process of entering or replicating (or both) inside the tissue,” according to NPR.

According to a slew of studies, it is less severe than the previous variants because it does not cause as much damage in the lungs.

A study on hamsters and mice conducted by a consortium of US and Japanese scientists discovered that those infected with Omicron had less lung damage, lost less weight, and were less likely to die than those infected with other variants.

The Omicron variant is known to evade vaccine efficacy due to up to 36 spike protein mutations.

Another recent study led by researchers at MGH, Harvard, and MIT tested blood from people who received the Moderna, Johnson & Johnson, and Pfizer/BioNTech vaccines against a pseudovirus engineered to look like the Omicron variant.

They included people who had recently been vaccinated or had recently received booster doses, as well as people who had previously been infected with SARS-CoV-2.

The results showed that Omicron neutralization was ‘undetectable’ in the majority of vaccinated people.

The Omicron variant is known to evade vaccine efficacy due to up to 36 spike protein mutations.

“The study demonstrates that Omicron drastically escapes vaccine-induced immunity after primary vaccination series with mRNA-1273 (Moderna), BNT162b2 (PfizerBioNTech) or Ad26.COV2.S (Johnson & Johnson/Janssen) and exhibits increased infectivity in vitro, raising the potential for increased transmissibility,” said Wilfredo F. Garcia-Beltran, Department of Pathology, MGH at Boston.

“Strikingly, Omicron was 4-fold more infectious than wild type (the original version of the virus) and 2-fold more infectious than Delta,” Garcia-Beltran and colleagues wrote in their study.

The data suggests Omicron may be able to infect people at a lower dose than Delta or the original variant.

Inside the lung tissue, Omicron has been reported to be less efficient at infecting cells than delta or the original version of the virus.

“The infection is more focused on the bronchia than the lungs and very fast,” Marc Veldhoen, an immunologist at the University of Lisbon, posted on Twitter.

Scientists now need to measure the viral loads inside people’s respiratory tracts.

With Delta, people have, on average, 1,000 times more virus particles in their respiratory tracts than with the original variants.

“I want to see what the viral loads look like for Omicron. Samples from people who are actually infected — that’s the gold standard. That’s where the action is,” said Garcia-Beltran.

On November 26, 2021, the WHO designated variant B.1.1.529 a variant of concern, named Omicron.

Many aspects of Omicron are being studied by researchers in South Africa and around the world.

According to the WHO, “all variants of Covid-19, including the Delta variant that is dominant worldwide, can cause severe disease or death, particularly in the most vulnerable people, and thus prevention is always key.”

Individuals can reduce the spread of the Covid-19 virus by keeping a physical distance of at least 1 metre from others, wearing a well-fitting mask, opening windows to improve ventilation, avoiding poorly ventilated or crowded spaces, keeping hands clean, coughing or sneezing into a bent elbow or tissue, and getting vaccinated when their turn comes.