Reacción a "Reaction to early laboratory data on how antibodies respond to the omicron variant"

The in vitro trials that are underway are only trying to verify the loss of neutralising capacity of the antibodies generated by the vaccine due to mutations in the neutralising epitopes of the virus spicule, but the loss of neutralising capacity (partial, very unlikely to be total) does not indicate that the vaccine has lost effectiveness, because the cellular immunity generated is much broader and covers many more epitopes of the protein, so the cellular memory will almost certainly remain conserved against the omicron variant.

The only thing that will probably be observed is a greater contagiousness (transmissibility) as our immune system will not be able to neutralise the virus so quickly in the respiratory mucosa after vaccination. But this need not be alarming as long as there is no loss of effectiveness in the first objective of vaccination, which is to prevent serious disease. The partial loss of neutralising capacity of the antibodies generated by the vaccine, in itself, I do not believe is a reason to reformulate the original vaccine given the time and cost involved. It is much more important to vaccinate the unvaccinated.

In vitro cellular immunity results will take a few weeks longer because they are much more complex to perform. In any case, we must always wait for real-world behavioural data, monitor the evolution of the new variant, the course of disease in vaccinated and unvaccinated individuals and be very attentive to possible vaccine failures in fully vaccinated and immunocompetent individuals.

A partial loss of neutralising capacity of the antibodies generated by the vaccine is to be expected, but cell-mediated immunity to the vast majority of the epitopes of the spicule protein will be preserved. This will imply a greater capacity for contagion or even reinfection, which would be mild and would not imply a loss of vaccine effectiveness.

For the time being, it is unlikely that we are facing a scenario in which omicron is a true escape variant that would require reformulation of the initial vaccine and revaccination of the entire population, something that would take quite some time.