In a Brazilian metropolis, because of the many people who were already infected, they hoped that Corona would not return - in vain.
A study now points to mutations.
The Brazilian city of Manaus was the focus of the first corona wave - researchers suspected herd immunity here.
A recently published study has taken another look at the phenomenon - with a view to virus mutations.
The team of scientists is now urgently advising to investigate the issue of secondary infections more closely.
São Paulo / Oxford - The concept of herd immunity without vaccination is crumbling, at least with Sars-CoV-2.
What is meant by this is that once infected, they are henceforth immune to the virus.
The first to come to mind is Sweden with its “Sonderweg”, which was assumed to strive for this (the government there vehemently denies this).
And Brazil, which with Manaus had a kind of “model city”.
According to a study, in October 2020 more than 70 percent of the approximately two million inhabitants were infected with the novel corona virus.
So herd immunity?
Researchers set the critical threshold at 60 to 70 percent.
However: The second wave hits Brazil with force.
Manaus too.
Study on corona herd immunity: infection rate of the mutation as a danger
Merkur.de * had previously reported doubts about herd immunity.
According to a virologist, not everyone infected has enough antibodies to be protected enough against a second infection - and the new mutations (Brazil, Great Britain, South Africa) are also an important factor.
A new
study published
in the specialist journal
The Lancet
also revolves around them
.
The research team in São Paulo and Oxford looked for reasons for the renewed corona outbreak.
Your theses:
There was never herd immunity in Manaus - the extrapolation of the study just mentioned was too optimistic (see second infection in the case of a lack of antibodies).
The immunity after the first wave has decreased - the researchers believe that this is an unlikely explanation.
Corona mutations reduce immunity: The much-noticed virus variant P.1 is currently spreading in the country.
The team sees evidence that she may be more resistant to antibodies directed against the previous pathogen.
Mutant P.1 could be significantly more contagious: According to the researchers, it shares characteristics with the pathogen B.1.1.7, which was discovered in Great Britain and which is apparently more infectious.
Corona mutation in Brazil: Entry bans due to "P.1" protests against Bolsonaro
Brazil is one of the countries hardest hit by the pandemic in the world.
More than 223,000 people have died there in connection with or from Covid-19 - that is the highest number after the USA.
The corona mutant P.1 has now also been found in other countries.
In Germany, Brazil is currently - like other high-risk areas - an entry ban.
There were protests against President Jair Bolsonaro in several Brazilian cities over the catastrophic situation.
“Tropical Trump”, as critics call him, had repeatedly played down the pandemic.
The far-right head of state also questioned the effectiveness of vaccines.
According to a recently published survey by the Datafolha Institute, Bolsonaro's popularity has declined: According to this, only 31 percent rate him as “good” or “very good” - in December it was 37 percent.
(frs)