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Spectators between cardboard friends in the Max-Schmeling-Halle in Berlin during a volleyball game
Photo: ANNEGRET HILSE / REUTERS
The global vaccination campaigns are raising hopes that the corona pandemic will end soon.
But instead of the much-invoked herd immunity, some scientists prefer to speak of the "new normal".
However, this is not a devaluation of the vaccinations, because they still have the potential to take the horror of the pandemic.
According to projections, the pandemic will come to a standstill on its own if enough people are immune, either because they have been vaccinated or because they have become infected.
When herd immunity could be achieved depends on how quickly the pathogen spreads.
Epidemiologists measure this with the reproduction factor, the famous R-value, which even laypeople are now familiar with.
However, this depends on many factors, for example whether more contagious variants spread or whether people adhere to hygiene rules.
Initially, experts assumed that in the case of the new Sars-CoV-2 coronavirus, herd immunity could be achieved if 60 percent of the people in the country are vaccinated.
Other estimates are now more likely to be 80 percent.
Free beer with vaccination
The first scientists are already completely deviating from the hope of herd immunity.
The data expert Youyang Gu recently renamed his well-known model "The path to herd immunity" to "The path to normality", reports "Nature".
According to the journal, there are five reasons for doubts about herd immunity:
Vaccines are not evenly distributed
.
While half of the people in Israel are already fully immunized, in the surrounding countries Lebanon, Syria or Egypt it is less than one percent.
The vaccination rate is also very different within individual countries such as the USA.
According to "Nature" in the US states of Utah and Georgia, less than ten percent are vaccinated, in Alaska and Mexico more than 16 percent.
In addition, there is currently no vaccine for children and adolescents.
The proportion of vaccinated adults should therefore be higher.
But in Israel the willingness to vaccinate is apparently declining.
Israeli authorities are already promoting the vaccination with free beer and pizza, reports data analyst Dvir Aran from the technological institute in Haifa.
New variants could endanger herd immunity
.
In Manaus, Brazil, it is estimated that more than 60 percent of people were infected.
In fact, the number of infections had initially decreased, but then the virus came back after the virus variant P1 spread.
If this can overcome the immune system despite surviving the infection, experts fear, it could also escape vaccination protection.
Immunity may not last long enough
.
According to initial studies, once infected people are often immune to Covid-19 for at least months, even if older people are more likely to be infected again.
How long the protection will last cannot be said for sure, because the virus has only been around since the end of 2019.
The same goes for the effects of vaccinations.
The protection may not last long enough for 60, 70 or even 80 percent of people to be immune at the same time.
It is still
not clear whether the vaccinations will also
prevent
infections
.
The first analyzes speak in favor of it, but so far there is no certainty.
As the vaccination progresses,
people may feel too safe
and no longer adhere to other rules.
Study: Vaccinations alone cannot stop a pandemic in the foreseeable future
According to a study recently published in The Lancet Infectious Diseases, a third wave threatens in Great Britain if measures are relaxed too quickly.
Vaccinations alone could not push the R-value below 1 according to the model calculations.
If all measures were abolished immediately, the value would jump to 1.58.
100 infected people would then infect an average of 158 more people, and the virus would inevitably spread.
This could result in 130,000 Covid deaths by January 2024.
The scientists admit that the vaccines could possibly protect better against deaths and serious illnesses than priced into the model calculations.
Nevertheless, they recommend loosening corona measures only slowly.
In particular, the vaccinations are no substitute for masks, contact tracking and tests.
"Then we breed these escape variants here in Germany."
The physicist and modeler Viola Priesemann from the Max Planck Institute for Dynamics and Self-Organization also warns of new mutations.
"In the worst case, a variant develops that forces us to start again with the vaccination from scratch," said Priesemann on Wednesday evening on the ARD talk show "Maischberger".
So-called escape variants developed where many people had already been vaccinated, explained Priesemann.
If many have been vaccinated and at the same time there is a high incidence, "then we breed these escape variants here in Germany," said Priesemann with a view to the upcoming summer.
Another reason to keep the number of new infections as low as possible.
So what does the future look like if the vaccinations may not bring herd immunity?
Long-term prognoses assume that Covid-19 could become endemic and break out again regularly, similar to the flu.
However, this is not necessarily a cause for despair.
Stopping the transmission of the virus is a way to return to normal, said Stefan Bottle, epidemiologist at the London School of Hygiene & Tropical Medicine, the journal Nature.
It is time for more realistic expectations.
Even if vaccinations should not allow herd immunity, however, they reliably protect people from severe courses and could prevent deaths.
The Covid-19 disease may not go away completely, but its omnipotence will likely decrease.
With material from dpa