Sorry again for off-topic ...but a very informative interview
translated with google
According to Prof. Drosten
Covid19 started very likely in the Chinese fur industry
www.republik.ch/2021/06/05/herr-drosten-woher-kam-dieses-virusMr Drosten, you have been researching coronaviruses for seventeen years. Most of us have only known such viruses since January 2020. How did coronavirus become the focus of your work?
In 2003, a doctor in Singapore contracted an unknown virus. Then he flew to New York, and there he got sick. It was known that he had been in contact with seriously ill patients in Singapore. On the return flight, the plane landed in Frankfurt for a refueling stop. The man was taken off board and placed in an isolation ward. At that time I was working in Hamburg at the Tropical Institute, which looks after imported infectious diseases, and had just developed a laboratory method that can identify viruses that had never been seen before. That's how I got involved in this detective story. At that time it was already epidemiologically clear that something was going around that was new, transmissible and triggering pneumonia, but nobody knew what kind of virus that was.
How did you proceed?
I was just in Frankfurt for my doctoral examination and visited colleagues there. They had just started their first cell culture and gave me samples. I applied the new method, and it turned out that there were sequences in it from a coronavirus that was not yet known.
And that is the story of the discovery of Sars?
After that, it was only a few more steps together with the colleagues from Frankfurt to show that it was this virus that had made the doctor so sick. At the same time, the Centers for Disease Control and Prevention in Atlanta had additional sample material from a second patient, a WHO doctor who had died of this disease in the intensive care unit in Bangkok. We were able to show through a joint investigation: two patients who have never met, but who both had an indirect epidemiological connection to China, where the first outbreaks of this disease had been registered, got sick in the same way from the same virus.
How long did this detective work last?
The main thing happened in a week.
In 2012, you also played an important role in the Mers coronavirus, which causes a serious infectious disease that is often fatal.
It was seen then that the same disease appears regularly in hospitals in the Middle East and is passed on between hospitals. You saw: there is an extremely deadly virus. Those who were originally infected may each infect another person, who in turn infected another - before the virus soon died out. So it was not transmitted from person to person on a permanent basis. Still, it kept popping up. Where from? It had to come from an animal that is in constant contact with humans, most likely a farm animal.
How did you go about it?
All types of farm animals were looked through. It wasn't a long process.
And how could you corner the virus?
Yes. Various laboratories have teamed up and tested all farm animal samples from the Middle East that were available for antibodies. One saw: the camel is it. The virus is often carried into hospitals by older men who deal with camels. In Saudi Arabia, camel breeding is, to put it casually, a kind of men's hobby.
What did you do then? Shot all the camels?
The best thing is to vaccinate the virus from its source. You can vaccinate the camels. There are farm animals, they are available, they are standing around. But camels sometimes have extreme sales prices and their owners often do not want to have them vaccinated: For many owners, if you stick a vaccination needle into it, it is like the S-Class getting a scratch. Sometimes that triggers very similar feelings.
They said this virus is transmitted from person to person two, three, four times. Why does Mers run dead afterwards, but not other coronaviruses?
First of all: a respiratory virus like Mers, which is transmitted from person to person at all, is of course much closer to a pandemic than other zoonotic viruses like rabies. Rabies is transmitted again and again from animals to humans, but then rarely continues from person to person. The decisive factor is that viruses are always adapted to their host, Mers to the camel. So if the virus wants to learn to transmit itself better from person to person, then this adaptation, i.e. the corresponding mutations, must take place in people. The virus does not learn that in the camel. For that, those initial two, three, or four generations of human-to-human transmissions are absolutely essential. Even so, a pandemic does not come about that easily.
Why?
A virus that is just at the beginning of a pandemic is not yet so highly contagious: an infected person is usually more likely to infect one person than five or ten. So there is only a limited amount of virus in circulation, and so only a limited number of mutations can arise. These mutations are always random. And coincidence, as evolution shows, rarely leads to a fairly optimized organism becoming even better. The virus is usually on the verge of extinction in humans - unless it produces the right mutations quickly enough and by chance.
A pandemic doesn't come about that easily, you say. Is that the reason that, despite decades of coronavirus research, you were surprised by Sars-CoV-2?
That a pandemic can come is clear to anyone working on viruses that jump from animals to humans. We had worked on Mers for several years and saw: This virus has the first foot or the first toe in the door. I was surprised by the current Sars-2 because I ... Yes, well, ultimately, because until recently I lived in the naive idea that the transitional landlord, that was with Sars-1 crawling cats and raccoon dogs, that this is in principle controlled in China.
What does it mean that the transitional host is controlled?
It is not as if one has to assume that bats bring such a virus directly to humans. I myself examined Sars-like coronaviruses in bats in field work. These Sars viruses in bat populations are also found in Europe. It can be shown in the laboratory that they are not so easily transferred from bats to humans. So you ask yourself: which animal is in between? Often these are farm animals that are crammed together in large herds, in which the virus can boil up. Humans interact with these animals differently than with distant wild animals such as bats. Take fur animals. Raccoon dogs and crawling cats have their fur pulled lively over their ears. They emit death screams and roar, and aerosols are created in the process. Humans can then become infected with the virus. These animals were clearly the source at Sars-1. That is scientifically proven. For me it was a closed story. I thought that this type of pet trade had been stopped and that it would never come back. And now Sars has come back.
How did it come back?
There are different hypotheses. That’s another big topic in the media right now.
„There is the thesis: This virus could have escaped from a laboratory. This is supported by the fact that Sars-2 is particularly contagious for humans. So far it is not possible to explain how this came about through natural selection. You can do that with Mers and Sars. Then there is the thesis that the virus mutated on Chinese fur farms. Mr. Drosten, where did this virus come from?
I am also thinking in the direction of the fur industry. This laboratory hypothesis does exist, of course. If you look at it from a purely technical point of view, if you just look at the genome, that's within the realms of possibility. But I can say: I know the techniques very well that you would need to change a virus in this way. If someone had developed Sars-2 in this way, I would say they made it pretty awkward. It shouldn't have been so difficult.
What do you mean?
There are actually two laboratory theses. One would be malice that someone has intentionally constructed such a virus. The other would be the research accident, that in spite of good intentions and curiosity an experiment went wrong. The malevolent thing, to be honest: you have to talk to the secret service about it. As a scientist, I cannot judge that.
And what about the research accident?
If you were to think about it now, you wanted to change certain things: The most striking thing is the so-called furin cleavage site, the furin cleavage site, a genetic property of the virus' spiky protein.
The furin cleavage site: With Sars-2, it ensures that the virus can better penetrate the human cell?
Yes exactly. So, let's imagine someone wanted to see what happens if you give a coronavirus this furin cleavage site that you know from influenza viruses: does it make it more malicious? For this I would take the Sars-1 virus, in a form that I can also change in the laboratory. So a DNA clone. Do you understand me?
We try it. Explain it to us.
You can't just put a virus in a glass dish and do some kind of experiment with it. Building a DNA clone like this from a virus takes two to three years of molecular biological work. Incidentally, researchers actually made such clones from the original Sars-1 virus. So if you had wanted to develop a kind of Sars-2 in the laboratory, you would have added changes, for example this furin site, to such a Sars-1 clone. To find out, does this adaptation make the Sars virus more contagious? But that was not the case here. The whole backbone of the virus is different: Sars-2 is full of deviations from the original Sars-1 virus.
What does that mean: the whole backbone is different?
Let me explain it with a picture: To check, for example, whether adjustments make the virus more contagious, I would take an existing system, incorporate the change and then compare it with the old system. If I want to know whether a new car radio improves the sound, I take an existing car and replace the radio there. Then I compare. I'm not building a completely new car for it. But that's exactly how it was with Sars-2: The whole car is different.
And that means?
This idea of a research accident is extremely unlikely for me because it would be far too cumbersome. The idea of malicious use by some secret service laboratory somewhere: if anything, something like that would probably not come from the Wuhan Virology Institute. This is a reputable academic institute.
What is the most plausible for you?
Carnivore breeding. The fur industry.
Why?
I have no evidence for this, except the clearly proven origin of Sars-1, and this is a virus of the same species. Viruses of the same species do the same things and often come from the same source. In Sars-1, this is scientifically documented, the transitional hosts were raccoon dogs and crawling cats. That is assured. It is also certain that raccoon dogs are used extensively in the fur industry in China. If you buy a jacket with a fur collar anywhere, it is the Chinese raccoon dog, almost without exception. And now I can tell you that there are no studies in the scientific literature - none at all - that shed light on the question of whether raccoon dog breeding stocks or other carnivore breeding stocks, for example minks, carry this virus, Sars-2, in China .
How is that possible?
I cannot answer that. All I can tell you is just going there, swabbing and doing PCR.
Why not do that? Wouldn't it be essential to know how the virus came to humans?
There is no published study on this. In 2003 and 2004 there were large studies that were made in China and which proved the connection to raccoon dogs and crawling cats for Sars-1.
Do we understand you correctly: The world was upside down for a year because of a pandemic, we are all making a huge effort here to make this virus disappear - but you didn't even go to the possible place of origin and cut back on it?
There was a WHO visiting mission in China. But the breeding stocks, which are distributed in many regions of the country, should of course be looked at systematically. Samples would have to be taken across the country. I don't know if Chinese scientists do that. It cannot be ruled out. I don't know if there won't be a study coming out next week that will explain this. It can be anything. I can only tell you: I have no information on this.
Why didn't you come to China with this WHO commission?
In principle, I am ready to get involved. In the specific case, the WHO, which put the mission together, did not approach me.
Back to the fur farm: can you explain how it works? In your opinion, how did Sars-2 come from the bat via the transitional host, the Chinese raccoon dog, into humans?
Fur animals are predators. They eat small mammals. They also chase bats in the wild. And bats only have one short window a year where they all have their young at the same time. A lot of newborns fall from the ceiling and they lie on the floor. And these wild cats know that. They go into bat caves and eat their fill. This is a holiday season for some, there is a lot to eat. And they can catch such viruses in the process. Some of these fur farms are wild animals, so wild-caught animals are added over and over again. That’s why it’s easy to imagine that such viruses will be introduced into these breeds. And you can watch TV reports how it then works, this fur harvest: This is an industry with close contact with people, where they can become infected.
What can you do if you discover a virus in such a company?
These are breeding farms. There's a fence around it. All animals could be vaccinated. If you had a vaccine. Of course you can also cull the whole population, as was done in Denmark, so that the virus is gone again. It doesn't come back so quickly either, at least not in this variant. What you have to realize, of course, is that if you were to examine such stocks now, you might not find the virus that was there - possibly - a year and a half or two ago. If there was a cull in between. Or if the virus has died in some other way.
Since the turn of the millennium, we've seen Sars-1, Mers, then Sars-2. What's happening?
For the two Sars pandemics, one can say: fifty or sixty years ago, when an intercontinental flight was the exception and only diplomats flew to China, for example, and trade with Asia was carried out via shipping containers - at that time such a virus would not have spread so easily. Travel makes it easier for a local epidemic to turn into a pandemic. At the source, at the transition from animals to humans, we humans use more and more land in the wild animal area and intensify livestock husbandry. The hunger for meat of growing humanity. The denser and larger the animal population, the greater the chances that a virus, once it is introduced into the population, will explode and mutate like Sars-2. The richer people get, the more they use animals. Mers is a good example of this.
In what way?
The camel as a religious sacrificial animal has a long tradition and is very valued. But it also costs a lot of money. Poor religious people take sheep instead. But the more people got rich in that region, the more camels were sacrificed. For example, during the Hajj season on the Arabian Peninsula, 40,000 camels are slaughtered every year as sacrificial animals. Fifty years ago that didn't even begin to exist. Ultimately, wherever in the world, it is about the modification of natural systems: a large population of livestock in any place is always something artificial. Animal use does not exist in nature. No species uses any other species in this way.
In Switzerland there is hardly any discussion about how we got into this pandemic, but all the more violent when we get out of it as quickly as possible: a third of the population has now been vaccinated at least once. Restaurants, bars, shops, wellness - everything is open. The summer comes. The number of infections is falling, although it is still at a high level, but it is falling almost continuously. Is the pandemic over with us, with our vaccination rates?
What we are discussing here as a pandemic is: An infectious disease is spreading in such a way that you have to intervene, even if it is with lockdown measures, because you have nothing else. Now we have something extra that reduces transmission much better than contact measures: vaccination. Both together and the warmer temperatures, which reduce transmissions by around 20 percent, means that the numbers are going down. The trick now is not to reduce the measures too quickly, otherwise it will hit back again exponentially. But to tare it with a certain sense of proportion. Of course, that has to be done by politicians, which are not acting purely on a science-based basis, but rather with a certain compromise on objectives. If things go on like this now, with a sense of proportion, and if the pandemic is defined as we have just done: then, yes, the situation will then be over.
Will we soon have herd immunity?
Explain what you mean by that.
Herd immunity is when, depending on the source, 70 or 80 or 90 percent have been vaccinated or have become immune from illness and then the virus can no longer circulate. This means that the non-vaccinated are also protected.
Yes. That won't work here.
What do you mean?
This was a misunderstanding from the start, if you took it to mean that herd immunity means: 70 percent will become immune - regardless of whether through vaccination or infection - and the remaining 30 percent will no longer have any contact with the virus from then on. It's just not the case with this virus. Anyone who does not get vaccinated will become infected with Sars-2. The term herd immunity comes from veterinary medicine, where such considerations were actually made in earlier years, for example with the rinderpest virus, the measles virus of cattle. Highly transmissible, but with a vaccination to keep it away for life. Then you can really do such calculations: We have a livestock population that is self-contained - how many of the animals do we have to vaccinate now so that the virus cannot circulate? That's where this term comes from.
Humans don't live in flocks.
Humans are not a closed group. We have travel and exchange and continuity, so even without traveling there is the neighboring village, and that has a neighboring village again, and so it goes on, around the world. And this is how viruses will spread, according to their basic ability to spread. In a few years, one hundred percent of the population will either have been vaccinated or infected. Even after that, Sars-2 will still infect people, but these will no longer be initial infections. The initial infection is the stupid thing, after that the disease that causes it is less bad. It will probably be some kind of, yes, I want to say: get a cold.
We have talked a lot about global vaccination inequality over the past few weeks. As long as billions of people have not yet been vaccinated, this virus can continue to mutate. Or will he run out of tricks at some point?
Presumably the latter is the case.
Why?
To understand this we need to talk about the immune system. Different parts of the immune system protect us from infection and disease. Antibodies that protect us from infection subside quickly and can only recognize the virus in a few places. So we can get infected again relatively soon, especially if the virus has mutated precisely in those places.
But?
But we only get slightly sick. Because that part of the immune system that protects us from disease is much more sustainable. The vaccination therefore probably actually protects us from getting seriously ill for several years. Responsible for this are the so-called T cells, which have been talked about constantly for a year: unlike antibodies, they don't really care if the virus mutates a little: T cells can recognize it on the basis of many different characteristics. The virus can easily lose some of its characteristics through mutations.
So that means: the worries that the virus that is floating around will mutate and that the current vaccinations will soon be worthless are not justified?
What you can see: The difference between the virus variants that have appeared on different continents is not that great. From a virological point of view, there are good reasons to assume that Sars-2 doesn't have that much more in store than what it has been able to show us so far. Coronaviruses mutate more slowly and less strongly than, for example, flu viruses, which actually have a much greater pandemic potential. I cannot imagine a mutant that suddenly gives the majority of those who have been vaccinated a serious illness again.
What about those who approach autumn unvaccinated - the children?
So purely technically: Yes, you can vaccinate them. It will hardly ever suddenly become clear that the vaccination is dangerous for children and that there is an undetected risk - after all that is already known today. The big question is about self-interest for the children: You can of course vaccinate so that the school runs smoothly. But what about the burden of disease in children? Nobody can say exactly at the moment. How many children continue to have symptoms after an infection, even if it is mild? A study has just come out that shows: about four and a half percent of infected children still have symptoms such as loss of smell, loss of taste and permanent fatigue after a month. Do you want that for your child? Four percent is not a small amount. The other is what is known as multi-system inflammation syndrome, which affects one in a few thousand: a serious illness that can last up to six months. From a parent's perspective, my child would be vaccinated. Clear case. I don't want this risk.