BA.2 Omicron Subvariant Similar To BA.1 In Severity Of Illness, Ability To Infect: Study

An international team of researchers have shown in a new study that the BA.2 subvariant of Omicron is similar to BA.1 in both severity of illness and the ability to cause infection.

Representative Photo | The scientists found that plasma from people who were vaccinated and then infected with BA.1 or earlier variants exhibited a smaller decrease in effectiveness against BA.2.

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New Delhi: An international team of researchers have shown in a new study that the BA.2 subvariant of Omicron is similar to BA.1 in both severity of illness and the ability to cause infection. Omicron is now the dominant version of SARS-CoV-2 and BA.2 is the dominant subvariant causing Covid-19 in nearly seven dozen countries. 

The peer reviewed study, led by University of Wisconsin-Madison virologist Yoshiro Kawaoka and his colleagues in Japan, was recently published in the journal Nature. The findings contrast with a recent study from another research team that relied on recombinant virus bearing spike proteins from BA.1 and BA.2.

How Was The Study Conducted?

In a statement released by University of Wisconsin-Madison, Kawaoka said the previous study indicates BA.2 may be more pathogenic than BA.1. But when the rescuers used an authentic virus, they found that BA.2 is not more pathogenic, Kawaoka said.

The researchers relied on rodent models for the disease. They tested viruses isolated from human samples, and observed that both subvariants of Omicron caused less severe illness compared to earlier strains, including Delta and the original strain of SARS-CoV-2 that emerged in late 2019, the study said.

Findings Of The Study

Existing therapeutic monoclonal antibodies and antiviral drugs were found to remain effective against BA.2. Monoclonal antibodies are man-made proteins that act like human antibodies in the immune system. 

The researchers observed that plasma from vaccinated individuals and from people who recovered from earlier infections was less effective at neutralising both subvariants of Omicron relative to earlier virus strains. Also, plasma from people infected with BA.1 was less effective at neutralising BA.2.

Then, the scientists found that plasma from people who were vaccinated and then infected with BA.1 or earlier variants exhibited a smaller decrease in effectiveness against BA.2.

Kawaoka said if one is vaccinated and then infected, they are protected against many different variants, especially compared to prior infection alone or vaccination alone. 

According to the statement, the team is now testing the newest subvariants of Omicron, including BA.2.12.1, which recently began spreading quickly in New York state.