Russia (bbabo.net) - Immunity acquired from a previous coronavirus infection is less effective against omicron than against other variants, so reinfections are on the rise, but the risk of severe COVID-19 remains low. Nature writes about it.
The researchers explain this feature by saying that the new variant is likely to be able to bypass the body's immune defenses. This conclusion was made by scientists from different countries, interviewed by Nature.
“Now the situation has really changed. We are talking about a variant with many properties that interfere with immunity,” says Light Abu-Raddad, an infectious disease specialist at a clinic in Doha (Qatar), who studies how post-vaccination immunity, as well as natural immunity, protects against Omicron in those who have been ill.
"Omicron's ability to infect people who have antibodies either after vaccination or after infection is a key reason why the recent spike in infections is so significant," said Marm Kilpatrick, an infectious disease researcher at the University of California at Santa Cruz.
Understanding the likelihood of reinfections is critical to assessing how high the spike in COVID-19 cases can be and whether hospitals can handle such a load, says Katherine Bennett, an epidemiologist at Deakin University in Melbourne, Australia.
The first data on the features of "omicron", including its ability to cause a recurrence of the disease in previously ill people, were obtained in South Africa. Now this is confirmed by studies conducted in different countries.
For example, according to the UK Health Protection Agency, more than 650,000 Britons are likely to have been infected twice, most in the past two months. Until mid-November, reinfections accounted for only about 1% of reported COVID-19 cases, but this has now increased to about 10%, an order of magnitude. Moreover, the true scale of re-infections can be much higher, because some cases remain undiagnosed.
Scientists are also trying to assess the level of protection of people from reinfection - these data are presented in an article published in the New England Journal of Medicine. The researchers calculated that natural immunity after experiencing COVID-19 was about 90% effective in preventing alpha, beta, or delta infection, and only 56% effective against omicron.
However, protection against the severe course of COVID-19 caused by "omicron" in those who had previously been ill remained high - about 88%.
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