December 6-12 2021
Will the Omicron variant able to break through protection conferred by vaccines?
Even though the Delta (Indian) variant remains largely dominant in France, the first cases of the Omicron variant have already been detected. It has become dominant in South Africa and has reached numerous other countries. It carries multiple mutations, many more than other variants. Its spike viral protein, which enables entry of the virus into the cell and which is the principal target of many antibodies that fight SARS-CoV-2, has 32 mutations compared to the original Wuhan strain. Scientists are therefore investigating whether the immunity endowed by anti-COVID-19 vaccines, which have now been in widespread use for several months, will remain effective against the variant.
There are many studies currently underway to investigate whether Omicron is more dangerous than other variants, but it will take some time before we have definitive answers. However, preliminary results suggest that the variant may largely escape the antibodies produced through vaccination: the Pfizer-BioNTech vaccine could be much less effective, up to 40 times less than against the original strain. Moreover, vaccinated individuals have already been infected by the variant. However, these initial results also show that a 3rd dose of the vaccine reinforces immunity against the variant, with an efficacy comparable to that attained by 2 doses against other variants. Several elements also seem to indicate that it is highly transmissible, and it has spread much more quickly than the Delta variant.
In conclusion, Omicron does seem to partially escape antibodies arising from vaccination, but a 3rd dose of the vaccine seems to enable immunity against the variant to be heightened. However, these results are only preliminary and it will be necessary to wait several weeks for them to be confirmed.