Omicron subvariant BA.2 could be more infectious, severe: WHO.
Highlights
- WHO recently cautioned countries eager to lift coronavirus precautions
- The fast-spreading and heavily mutated Omicron variant has rapidly become dominant variant
- BA.2 version of Omicron begins to replace more common "original" BA.1 version in Denmark
Omicron COVID subvariant: The emerging and fast-spreading BA.2 form of the Omicron coronavirus variant has been detected in 57 countries so far, the World Health Organisation (WHO) has said. It has also cautioned countries eager to lift coronavirus precautions, saying Omicron hasn’t yet peaked in many countries.
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According to some studies, the subvariant of the highly contagious Omicron strain could be even more infectious than the original version, the WHO added, however, there no confirmed report about it.
World Health Organization Director-general, Tedros Adhanom Ghebreyesus said, "It's premature for any country either to surrender or to declare victory. This virus is dangerous, and it continues to evolve before our very eyes. WHO is currently tracking four sub-lineages of the Omicron variant, including BA.2."
The fast-spreading and heavily mutated Omicron variant has rapidly become the dominant variant worldwide since it was first detected in southern Africa 10 weeks ago.
In its weekly epidemiological update, the World Health Organization said that the variant, which accounts for over 93 percent of all coronavirus specimens collected in the past month, counts several sub-lineages: BA.1, BA.1.1, BA.2 and BA.3.
Meanwhile, the current COVID-19 vaccines provide robust protection against severe disease and hospitalisation caused by both the Delta and Omicron variants, according to a study.
The research, published in the journal Nature on Monday, demonstrated that the vaccines induce this protection through cellular immunity or the production of protective immune cells, such as so-called killer and memory cells.
Cellular immunity continues to protect from severe COVID-19 disease despite the Omicron variant's evasion of neutralising antibodies, the researchers said.
The team at Beth Israel Deaconess Medical Center (BIDMC) in Israel assessed samples from 47 individuals vaccinated with either the Johnson & Johnson or Pfizer-BioNTech vaccines.
"Our data provide immunological context for the observation that current vaccines still provide robust protection against severe disease and hospitalisation due to the Omicron variant despite substantially reduced neutralising antibody responses and increased breakthrough infection," said corresponding author Dan H Barouch.
The researchers used samples from uninfected individuals who received either the Johnson & Johnson or Pfizer vaccines. They measured CD8+ T cell and CD4+ T cell responses to the original, Delta and Omicron strains of the SARS-CoV-2 virus after one month and then again after eight months following final vaccination.
Both CD4 and CD8 cells, also known as T cells, are white blood cells that fight infection and play an important role in the immune system.
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