OMICRON ANTIBODIES
Source: The Indian Express
Context
The current wave of Covid-19 highlights a high risk of reinfection by the Omicron variant of SARS-CoV-2.
How does Omicron evade Antibodies?
- Researchers analysed the antibody neutralisation capacity of 120 people infected with the original SARS-CoV-2 Strain or with the Alpha, Beta, Gamma, Delta, Zeta or Omicron (Sub-variant BA.1) Variants.
- They found that, unlike its predecessors, Omicron appears to be able to evade the antibodies generated by all other variants, the University of Geneva.
- The researchers, from the University's Centre for Emerging Viral Diseases and the Geneva University Hospital, have published their findings in Nature Communications.
- In vaccinated individuals, the neutralisation capacity is also reduced, it remains far superior to natural immunity alone.
- This could explain why Omicron is responsible for a net increase in vaccine breakthrough infections, but not in hospitalisations.
- The research team took blood samples from 120 volunteers previously infected with one of the different variants, unvaccinated or vaccinated and infected, either before or after vaccination.
- The aim was to determine how well the antibodies generated during the first infection were able to neutralise the different variants of SARS-CoV-2.
- "Omicron proved to be the most effective at evading pre-existing natural immunity as well as, to a lesser extent, that induced by vaccination," according to the researcher Benjamin Meyer.
- Anti-body levels against ancestral SARS-CoV-2 in vaccinated people are roughly 10 times higher than in people who have only developed post-infection immunity.
- The combination of the two, known as hybrid immunity, seems to maintain even higher and broader reactive antibody levels.
- Omicron can evade existing immunity and cause an infection but hospitalisation and death due to covid-19, even with Omicron, are still reduced after vaccination.
- Nevertheless, SARS-CoV-2 retains an astonishing ability to mutate.
- Vigilance is still required, especially as the epidemiological curves have been rising sharply since the appearance of BA.5, quoted researcher Isabella Eckerle.
