THE QUESTION
.
They thought the worst was behind them, and yet the people of Manaus (Brazil) are currently facing a dramatic outbreak of the Covid-19 epidemic, combined with saturation of hospitals and a shortage of oxygen tanks .
Watch the video: Covid-19: in Manaus, Brazilians must provide the necessary oxygen themselves to their sick relatives - Watch on Figaro Live
Last spring, this city - the most populous in the Amazon - had already paid a heavy price for the virus, recording a mortality 4.5 times higher than that usually observed.
A recent study published in the journal Science even suggested that 76% of the population was infected between March and October.
So some scientists expected group immunity to protect Manaus from a second wave.
However, this is not what happened.
How to explain it?
CHECKS
.
Group immunity is reached when a virus can no longer spread in a population, since it only encounters people who are already immune (naturally or via a vaccine).
In other words, it is when the virus has difficulty finding new "
virgin
"
organisms
to colonize and that it will, in fact, spread more difficult, or even die out.
In the case of Sars-CoV-2, the level of immunity needed to stop the epidemic has been estimated
This article is for subscribers only.
You have 79% left to discover.
Subscribe: 1 € the first month
Can be canceled at any time
I ENJOY IT
Already subscribed?
Log in