Those who have recovered from the Omicron coronavirus strain may have a fourfold increased immunity to Delta, according to scientists from South Africa.
Experts noted that there is every reason to believe that the Omicron strain could strengthen human immunity against the Delta variant and reduce its ability to re-infect. They examined 13 patients, seven of which were vaccinated against coronavirus with Pfizer or Johnson & Johnson compounds. Eleven patients were affected by Omicron.
Examining the antibody response, scientists found that participants who had contracted the Omicron variant had a more than four-fold (4.4) increase of neutralisation against the Delta variant two weeks after the research started. Apart from that, the patients were said to have a 14-fold increase in protection against reinfection by Omicron.
"The increase in Delta variant neutralisation in individuals infected with Omicron may result in decreased ability of Delta to re-infect those individuals", the scientists said.
The consequences of this displacement would depend on whether or not Omicron is less pathogenic than Delta.
"If so, then the incidence of COVID-19 severe disease would be reduced and the infection may shift to become less disruptive to individuals and society", they noted.
Researchers also warned that it's unclear what exactly contributes to the immune response – Omicron-induced antibodies, vaccinations, or immunity from previous infection. The study, led by Khadija Khan, has not yet been peer-reviewed by other experts, as it was published due to the urgent nature of the pandemic.
Earlier reports claimed that most of those affected by Omicron in South Africa showed mild symptoms that haven't led to hospitalisation. According to local data, these patients are 70 percent less likely to develop severe disease compared with Delta.
Last week, the head of the World Health Organisation (WHO) office in the Russian Federation, Dr Melita Vujnovich, suggested that the Omicron strain could become a "live vaccine" against COVID-19 and help defeat the pandemic. According to her, while this outcome is possible, there are not yet enough patients infected with Omicron to conduct a study.
Nevertheless, WHO Director-General Tedros Adhanom Ghebreyesus earlier confirmed the danger of the Omicron strain for those who have been vaccinated or have recovered from COVID-19.