Washington (AFP)
Contamination with the new coronavirus responsible for the Covid-19 pandemic protected macaques from reinfection 28 days later, according to a Chinese study published Thursday in the journal Science.
Immunity to the coronavirus following an initial infection, and its duration, remain unanswered questions in humans: it will be necessary to wait for other waves, and perhaps months or years, to know if the millions of people infected at the start of the pandemic are protected or not.
In the meantime, scientists from Peking Union Medical College have performed an experiment on rhesus macaques, usually used because of their similarities to humans, to find out if short-term immunity existed.
Six macaques were infected in the trachea with a dose of the SARS-CoV-2 virus. They developed mild to moderate symptoms, and took approximately two weeks to recover.
28 days after the first infection, four of the six monkeys received another dose of virus, but this time, despite a brief rise in temperature, they "did not show signs of reinfection with the same strain of SARS-CoV- 2 during their initial recovery period, "write the scientists.
The peak viral load in monkeys was reached three days after the first infection, the researchers also discovered, by taking frequent samples.
Thanks to numerous analyzes, they observed a stronger immune response after the first infection, with in particular more so-called neutralizing antibodies (blocking the virus), "which could have protected the same non-human primates against short reinfection term".
It will take other experiments to see how long this immune defense stays in place.
© 2020 AFP