The anti-Covid vaccines could lose part of their effectiveness in the face of the Omicron variant: this is suggested by five papers just published in the journal Nature and conducted by David Ho of Columbia University, New York on all vaccines in use, as well as on monoclonal antibodies approved as an anti-Covid therapy. Indeed, from a series of laboratory tests, it emerged that the neutralizing effect of the antibodies induced by vaccines in 54 subjects - including 15 subjected to the third booster dose - is low against Omicron.
The efficacy of monoclonal antibodies developed against other virus variants was also found to be low.
The vaccines in use against the coronavirus all work by inducing the immune system of the vaccinated to recognize and attack the Spike protein, therefore, the researchers explain, a reduction in the effectiveness of the vaccines against Omicron which has a Spike protein rather different from that of the previous variants of the SArs-CoV-2, with over 30 variations on its sequence. Experts also isolated 4 other new variations on Omicron's Spike protein.
To verify the effectiveness of the vaccines on Omicron, US experts studied the neutralizing activity of the four main anti-COVID-19 vaccines - Pfizer-BioNTech, Moderna, Johnson & Johnson,AstraZeneca - against Omicron on samples from 54 participants vaccinated with two doses (including 15 with booster doses of Pfizer-BioNTech or Moderna).
The researchers observed a significant decline in the efficacy of the Omicron vaccines, even with antibody samples from two participants who had previously tested positive for SARS-CoV-2.
However, for those who received the booster doses of Pfizer-BioNTech or Moderna, the researchers found a minor decline in the neutralizing activity of the antibodies.
Finally, the decrease in efficacy was also significant for 17 of the 19 monoclonal antibodies tested.
Only romlusevimab and sotrovimab are shown to remain effective even against Omicron, the researchers conclude.