A new study on the effectiveness of our immune response to variants of the Covid-19 was published this Friday in the British journal Nature Medicine .
What is the immunity of a person infected with the coronavirus several months ago if they encounter one of these variants? To find out, the authors of the study took the serum of people cured of Covid-19 infected with the “historic” strain.
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In this serum are the antibodies. Scientists have observed their behavior against the British and South African variants. For the first, even a serum taken 9 months after the first contamination remains just as effective, the English variant is neutralized in 95% of cases.
The efficiency drops to 60% and above all it takes a lot more antibodies – 6 times more – to be able to neutralize it. People with a weak immune response are therefore particularly at risk.
The researchers found that only 7% of the population had been infected with the virus, of whom more than 80% had had no symptoms. Around 40% of the infected people produced neutralizing antibodies that could be detected for the entire study period.
The researchers conclude that most people in Wuhan are still susceptible to SARS-CoV-2 infection, and that a mass vaccination campaign is needed to achieve herd immunity.
The researchers also wanted to determine what is the level of response provided by the vaccines, that of Pfizer in this case. A week after the second injection, the numbers are similar: just as effective against the British variant as against the historic strain, but only 60% against the South African.
This new study confirms the results of previous laboratory research, but goes further. This time the authors used authentic viral strains that came closer to what is seen in real life.