Researchers at Columbia University Irving Medical Center, in collaboration with colleagues from the University of Hong Kong, thus confirm Omicron’s immune escape capacity, both against vaccines and against natural infection. These results raise awareness of the need for new vaccines and treatments that even anticipate the possible – and continued – evolution of the virus.
Dr David Ho, MD, senior author and director of the Aaron Diamond AIDS Research Center recalls that a striking feature of the Omicron variant is the “alarming” number of changes in the spike protein of the virus that pose a threat to efficacy. current therapeutic vaccines and antibodies. Thus, the Omicron variant shares some common mutations with the Beta and Delta variants, it also has 22 additional substitutions (insertions and deletions) which are specific to it, in the state of current knowledge.
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Antibodies, natural and vaccine, less effective against Omicron
Here, researchers are testing the ability of antibodies generated by vaccination to neutralize Omicron in laboratory tests, both by opposing antibodies to Omicron-mimicking pseudoviruses and to live viruses. The antibodies were from patients doubly vaccinated with one of the 4 most widely used vaccines (Moderna, Pfizer, AstraZeneca, Johnson & Johnson). Experience shows that:
- the antibodies generated by these vaccinated individuals are significantly less effective at neutralizing Omicron vs. the original strain;
- the same goes for antibodies from previously infected people: these antibodies are even less likely to neutralize Omicron;
- people who have received a booster shot of one of the two mRNA vaccines are likely to be better protected, even if their antibodies still show reduced neutralizing activity against Omicron.
“These new data suggest that the vaccine and natural immunities mounted against the original strains are less effective against the Omicron variant and therefore that people vaccinated or previously infected remain at risk of infection” explains Dr Ho.
“Even a 3rd injection may not fully protect against infection with Omicron,
but this reminder remains advisable because it confers a certain immunity ”.
These data are in line with the findings of recent neutralization studies., as well as with the first epidemiological data from South Africa and the United Kingdom, which confirms that the efficacy of 2 doses of the vaccines against the symptomatic disease is considerably reduced against Omicron.
“Most monoclonal antibodies are unable to neutralize Omicron”: given early in the infection, monoclonal antibodies can prevent many patients from developing severe COVID. This study suggests that all of the therapies currently in use and most in development would be much less effective against Omicron,
assuming they work ”.
In neutralization studies carried out with monoclonal antibodies, only one (Brii198 approved in China) shows significant activity against Omicron. A marginal form of Omicron is also completely resistant to all the antibodies used in clinics today, the researchers say.
Omicron is the most comprehensive “escape” scientists have studied to date.
Especially since the Columbia team identifies 4 new cutting-edge mutations which further promote this immune escape.
It is now “To anticipate the evolution of the virus”, because it is no exaggeration to think that SARS-CoV-2 is only 1 or 2 mutations away from being completely resistant to current antibodies, whether monoclonal antibodies used as therapies or antibodies generated by vaccination or infection with the previous variants.
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