(ORDO NEWS) — A new omicron sub-variant of the virus that causes COVID-19, BA.2, is rapidly becoming a major source of infections as cases rise worldwide.
Immunologists Prakash Nagarkatty and Mitzi Nagarkatty from the University of South Carolina explain how it differs from previous options, whether there will be a new surge in cases in the US and how best to protect yourself.
What is BA.2 and how is it related to Omicron?
BA.2 is the newest sub-variant of Omicron, the dominant strain of the SARS-CoV-2 virus that causes COVID-19. Although the origin of BA.2 is still unclear, it quickly became the dominant strain in many countries including India, Denmark and South Africa. It continues to spread in Europe, Asia and many other parts of the world.
The Omicron variant, officially known as B.1.1.529, of SARS-CoV-2 has three major sub-variants in its ancestry: BA.1, BA.2, and BA.3. The earliest omicron subvariant discovered, BA.1, was first reported in November 2021 in South Africa.
Although scientists believe that all subvariants may have appeared at about the same time, BA.1 was predominantly responsible for the winter spike in infections in the Northern Hemisphere in 2021.
The first sub-variant of Omicron, BA.1, is unique in the number of changes it made to the original version of the virus – it has more than 30 mutations in the spike protein, which helps it enter cells.
Mutations in the spike protein are of great concern to scientists and public health officials because they affect how contagious a given variant is and whether it is able to evade the protective antibodies that the body produces after vaccination or prior infection with COVID-19.
BA.2 has eight unique mutations not found in BA.1 and does not have the 13 mutations found in BA.1. However, BA.2 shares about 30 mutations with BA.1. Due to relative genetic similarity, it is considered a sub-variant of Omicron rather than an entirely new variant.
Why is it called the “stealth variant”?
Some scientists refer to BA.2 as a “hidden” variant because, unlike the BA.1 variant, it does not have a distinct genetic signature that distinguishes it from the Delta variant.
While standard PCR tests are still able to detect the BA.2 variant, they may not be able to distinguish it from the Delta variant.
Is it more contagious and deadly than other options?
BA.2 is considered more transmissible, but not more virulent than BA.1. This means that although BA.2 may spread faster than BA.1, people may not get sick more often from it.
It is worth noting that although BA.1 dominates the number of cases worldwide, it causes less severe disease compared to the Delta variant. Recent studies from the UK and Denmark suggest that BA.2 may pose the same risk of hospitalization as BA.1.
Does previous BA.1 infection provide protection against BA.2?
Yes! A recent study showed that people previously infected with the original BA.1 subvariant have strong protection against BA.2.
Because BA.1 has caused widespread infection worldwide, it is likely that a significant percentage of the population has protective immunity against BA.2. That is why some scientists predict that the likelihood of BA.2 causing another major wave will be lower.
However, while natural immunity acquired after infection with COVID-19 can provide reliable protection against re-infection with earlier variants, it weakens against Omicron.
How effective are BA.2 vaccines?
A recent peer-reviewed pilot study of more than 1 million people in Qatar found that two doses of Pfizer-BioNTech or Moderna COVID-19 vaccines protected against symptomatic BA.1 and BA.2 infection for several months and then drop to about 10 percent.
However, revaccination was able to raise the level of protection back to almost the original level.
It is important to note that both vaccines were 70-80% effective in preventing hospitalization or death, and this efficacy increased to more than 90% after an additional dose.
How concerned should the US be about BA.2?
The increase in BA.2 cases in some regions of the world is most likely due to a combination of higher transmissibility of the virus, weakened human immunity, and loosening of restrictions on COVID-19.
CDC data suggests that the number of cases of BA.2 is steadily increasing and, as of early March, accounts for 23% of all cases in the United States. Scientists are still arguing about whether BA.2 will cause a new surge in cases in the US.
Although BA.2 infections are likely to increase in the coming months, protective immunity from vaccination or previous infection provides protection against severe illness.
This may reduce the likelihood that BA.2 will cause a significant increase in hospitalizations and deaths. However, the US lags behind other countries when it comes to vaccinations, and lags even further behind when it comes to revaccination.
Whether another devastating surge occurs depends on how many people are vaccinated or previously infected with BA.1.
However, developing immunity from a vaccine is much safer than from contracting an infection.
Getting vaccinated and taking precautions like wearing an N95 mask and social distancing are the best ways to protect yourself from BA.2 and other varieties.
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