Omicron infection would confer low quality immunity

In March, nearly 80% of French people had a complete vaccination schedule and nearly 60% had received the booster. Yet the virus is spreading and the numbers of theepidemic have been on the rise in recent days. Notably, the effective R is greater than 1, which means the virus is actively circulating.

It’s the Omicron variant which is currently the majority, in France and in the world. It is more transmissible than its predecessors. The vaccines are less effective against the variant Omicron only against the original strain of the virus, which led the government to carry out the campaign to recall the vaccination. However, it is less dangerous. While the number of new daily cases was close to half a million at the end of January 2022, the number of hospitalizations fortunately did not soar.

However, between people who have already had the virus and those who are vaccinated, how is it possible that there are still more than 80,000 new contamination per day ? According to a study recently published in Cellit could be that the immunity conferred by the Omicron variant of coronavirus provides only low quality protection. In other words, it would be possible to be contaminated several times.

A study in vaccinated subjects

The authors of this study were interested in the rates ofantibody neutralizers against the Delta variant, against the Omicron variant and against the original strain of SARS-CoV-2 in fully vaccinated individuals, some of whom also received the booster dose. They analyzed 259 samples from 128 patients.

Without surprise, they observed that levels of neutralizing antibodies decline over time in vaccinated individuals. Furthermore, the more clinically severe the infection, the higher the level of neutralizing antibodies.

Differences between Omicron and Delta infection

Infection with the Omicron variant of SARS-CoV-2 generates much lower levels of antibodies than those generated by contamination with the Delta variant. This may be partly explained by the fact that an infection with the Delta variant triggers more discreet clinical pictures.

In conclusion, an infection by the Omicron variant generates much lower subsequent protection than that which was generated by an infection by the Delta variant. This means that a person infected with Omicron would be fairly poorly protected on the one hand against reinfection with Omicron and on the other hand against infection with another variant.

To counter the occurrence of a new variant potentially more contagious and more dangerous, it is necessary to limit the circulation of the virus. Because the more the virus circulates, the more opportunities it has to carry out a mutation.