According to experts, the third dose should provide adequate protection for the Omicron variant as well. If not, Pfizer could develop an ad hoc vaccine in 100 days. Modern too is already at work
The Omicron variant is spreading rapidly, even in Europe (a first case has also been identified in Italy): could it pierce the vaccines available today?
Strain B.1.1.529, reported on November 24 in South Africa, has numerous mutations, some of which have already been seen – separately – in the previous variants Beta, Gamma and Delta. From the first data we know that Omicron is most likely more infectious than Delta, ie it spreads rapidly, but for now it does not appear to be pathogenic anymore. It will take a few weeks to figure out if it escapes the immune system of the vaccinated.
We have three hypotheses before us – he underlines Carlo Federico Perno, director of the Microbiology Unit at the Bambino Ges pediatric hospital in Rome -. The first (probable) that Omicron, as happened to the Alpha, Beta, Gamma and Delta variants, does not escape the coverage offered by current vaccines. The second: mutations produce a change in the Spike protein that makes it less sensitive to the immune system. In this case (possible) the efficacy of the vaccines remains good, but falls compared to what has been observed so far with Delta. In the third scenario, which I think is highly unlikely, the Spike protein is so mutated that the vaccine is no longer effective. If so, we would have to start the cycle over with a new vaccine. I consider this remote option because the antibodies cover the area of the Spike protein that binds human cells: if that specific part were to change significantly, the virus would risk being unable to attach to our cells anymore. Remember that it is not the amount of mutations that need to worry us, but possibly their quality and the final conformation of the Spike. In the summer of 2020, a single mutation, D614G, quickly supplanted all previous strains.
Will the third dose protect us from the Omicron variant?
In all vaccines, the third dose stabilizes the immune response in the long term (even for life), therefore it is reasonable to believe that the third injection can also increase protection against Omicron, unless the option for which the strain it completely escapes the vaccine-induced immune response. With the booster we should reach antibody levels such as to be able to cover this variant too – said Rino Rappuoli, research and development manager of GlaxoSmithKline Vaccines, as well as scientific coordinator of the Mad Lab of Toscana Life Sciences -. We know that the third dose is indispensable for long-lasting immunity and to cover variants; in a year we will see if there will be a need for a fourth or fifth dose. It depends on how we vaccinate the rest of the world: in Africa just 6% of the population immunized.
If new vaccines are needed, when will they be available?
According to Pfizer, a possible vaccine against Omicron can be developed in 100 days. The company is studying the variant and has announced that within a couple of weeks it will be able to understand if it escapes the immune system. Moderna is also working on it: We have three lines of defense running in parallel: a booster with a higher dose (100 mg); two candidates booster multivalents that anticipate mutations such as those that emerged in the new variant; a specific candidate (mRna-1273.529) said Stphane Bancel, chief executive officer of the US company.
possible a further increase in infections?
In a report, the European Center for Disease Prevention and Control (Ecdc) writes that the overall level of risk associated with the Omicron variant is rated as high to very high. To avert this, he explains, genomic surveillance remains of the utmost importance and it is strongly advised to avoid travel to and from known affected areas (the first cases have been reported in South Africa and Botswana. ed). European countries are urged to give the highest priority to vaccination of non-immunized or partially covered individuals and to consider the dose booster.
November 28, 2021 (change November 28, 2021 | 14:07)
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