COVID-19: omicron infection increases neutralizing immunity against delta, according to South African study

Infection with the omicron variant of SARS-Cov-2 creates a neutralizing immune response against delta, which may make reinfection with the latter less likely.

If this lower capacity of delta to infect those who have passed omicron is combined with the data that indicate that the new variant, at this time, is less pathogenic, this result may have positive implications in terms of reducing the burden of COVID-19 of serious illness.

Study leader Alex Sigal of the African Health Research Institute (South Africa) indicated that, if “omicron turns out to be less pathogenic, this may show that the course of the pandemic has changed”. “Ómicron will take over, at least for now, and we may have fewer disruptions in our lives. “

The research, carried out with a small sample of patients, was published in the MedRxiv repository, where the texts have not yet been reviewed by other experts.

Omicron infections are spreading rapidly around the world, often even in the face of high levels of delta cases, and it is still unclear how these two variants will interact.

“Increased neutralization of the delta variant in omicron-infected individuals may lead to a decreased ability of delta to re-infect these individuals.”Said the Sigal.

The study analyzed plasma from 15 previously vaccinated and unvaccinated people who passed COVID-19 during the great wave of infections in South Africa with the emergence of omicron.

The objective was to test the ability of the antibodies to control both variants in the laboratory, known as the “neutralization”, Which was performed around the time they had their first symptoms and fourteen days later.

As expected, the results show a developing antibody response to omicron, with a 14-fold neutralization during this time.

But, in addition, it was seen that they developed a greater immunity against the delta variant, with an increase in the neutralization of the latter of 4.4 times.

The study also indicates that vaccinated participants were able to mount a better neutralizing response against delta, while the response in the unvaccinated was more variable.

On the contrary, the study points out, omicron escapes the neutralizing immunity caused by delta and, therefore, can re-infect individuals already infected by it.

These results are consistent with the fact that omicron is displacing delta, since it can provoke an immunity that neutralizes the latter.

The implications of this shift would depend on whether omicron is actually less pathogenic than delta. “If so, the incidence of severe disease COVID-19 would be reduced and the infection could shift to be less disruptive to individuals and society.”, Conclude the authors