Sitting relaxed together, without worrying about infection - who doesn't want that?
Photo: Sven Hoppe / DPA"What if herd immunity was closer than scientists thought?" Asks the New York Times in a major article. Instead of the initially assumed 60 to 70 percent immune people in the population, it might only need 50 percent - or even less. Some experts believe that herd immunity may already be reached at 20 percent. Then we could defeat the coronavirus much easier than we thought, so the assumption.
Oh, that would be nice! Just a few more infections and everyone could go back to their old life, with parties without worries, shopping without mouth and nose protection and long-haul flights where you just have to have a guilty conscience because of the climate.
But that's not going to happen. Three reasons herd immunity is most likely not working.
Viruses have other plans
"Trick question: How many circulating respiratory viruses do you know of that have caused herd immunity?" A virologist recently asked on Twitter. The researcher himself resolves: "None, otherwise they would not circulate. Viruses adapt to evade the immune response or to change it in order to survive."
In fact, other coronaviruses - just like countless other viruses - have been circulating for a long time without ever having said goodbye through herd immunity.
Even measles, which induce lifelong immunity, could ultimately only be permanently suppressed with the help of a vaccination. Before vaccination, the viruses kept finding new, non-immune hosts among young children.
Incredible suffering
Much more important than theoretical considerations about the evolution of viruses is the now clear recognition that coronavirus infections can be dangerous. Sure: Many of those affected cope with the infection with no or only mild symptoms. But a relevant proportion becomes ill, suffers permanent damage or dies.
Even places with large outbreaks are still a long way from herd immunity: in New York, for example, around 21 percent of people have antibodies. It is still unclear whether these actually protect against a second infection.
According to antibody studies, however, one region in Europe may be close to herd immunity: In the Italian province of Bergamo with the capital of the same name, 57 percent of the population have antibodies against Sars-CoV-2. The Italian National Statistical Institute shows how many people died in Bergamo in the past few months - and how many there were on average in the respective months in previous years: In March 2015 to 2019, an average of 897 people died in the province, in March 2020 there were 6059. Also in April 2020 there were more than twice as many deaths as in the previous months: 1801 compared to 796. About 1.1 million people live in Bergamo.
If you want to clarify the situation on site differently: Here you can read what the mayor of Bergamo said on March 18 from the city's clinics, here you will find the diary of a man from the Italian city.
In addition, people who survive Covid-19 according to such statistics can suffer permanent damage. There are increasing reports of those affected who have been seriously ill for months, even if the frequency of these problems cannot yet be quantified.
The virologist Sandra Ciesek, professor at the University Clinic Frankfurt, answered the question of whether herd immunity was achievable, therefore to SPIEGEL: "First of all, this path is not at all desirable because the virus causes a lot of damage and a lot of people die would. "
The fact that Germany had comparatively few deaths in connection with the coronavirus at this time is due to the fact that the idea of achieving herd immunity was not seriously touted here.
Without long-term immunity, there is no herd immunity
One of the big questions about the coronavirus cannot yet be answered clearly, namely how long the immunity to the pathogen lasts after an infection. At least at the moment there is encouraging evidence that immunity could last long or long term, but this cannot be said for sure. In other words: Even in Bergamo you cannot be sure that another coronavirus wave could hit many people again at some point. The hope is, of course, that the immunity will last, but if this is not the case, herd immunity cannot be achieved anyway, or only for a short time.
So what to do
To go on like this forever is unacceptable. Again, allow the virus to spread freely, too. How can this be resolved? The solution is vaccines. There are currently 29 vaccine candidates in clinical trials, i.e. they are being tested in studies on volunteers. Another 138 preparations are in the preclinical phase: they are already being researched, but not yet tested on humans.
If some of these candidates prove effective and safe, we could actually achieve herd immunity - without paying a terrible price for it.
Icon: The mirror
