Georgy Bazykin: “China has issued the unprecedented quarantine in recent history”
The specialist in genetics and virus evolution about what is known to date about the coronavirus, which has provoked a mess among doctors all over the planet
Georgy Bazykin — the molecular biologist, PhD, Professor at Skoltech and the head of the Molecular Evolution Laboratory at the Institute for Information Transmission Problems of the Russian Academy of Sciences — in his interview with Realnoe Vremya speaks about the bad luck fallen on the ill-fated Wuhan, what we should expect from the new virus, where it came from and whether it is really a dangerous situation. Spoiler: all we know now for certain is that not everything is known, it is too early to panic, but there is already a reason to be alarmed.
“The virus we are seeing is a close relative of SARS”
What is the new coronavirus and where did it come from? Is it brand new or something similar has been observed before?
Mankind has already encountered such viruses before. This is a large group of viruses that infect animals — mostly warm-blooded. Many of them also attack humans — they usually cause a standard cold, which is quickly cured. Coronaviruses, for example, are responsible for some part of viral respiratory infection.
But there have been several cases of serious outbreaks of more severe infections caused by coronaviruses that looked very dangerous. For example, the severe acute respiratory syndrome (SARS) epidemic in 2002-2003 or several outbreaks of Middle East acute respiratory syndrome in the 2010s. And the virus that we are seeing now in China is a close relative of SARS.
Scientists are already talking about this with a high degree of confidence because this time its genomic sequence was obtained very quickly. If we compare it with the genomes of other known viruses, we can see that it is very similar to the human SARS virus of the 2002-2003 outbreak's sample. But it looks even more like a virus isolated from bat's biological samples. Based on this, it is assumed that this outbreak had bats as the source reservoir of the virus.
If we compare it with the genomes of other known viruses, we can see that it is very similar to the human SARS virus of the 2002-2003 outbreak's sample. But it looks even more like a virus isolated from bat's biological samples
So, a bat sneezed on a human, the virus liked to be there, and it spread in it?
It is possible that the primary transmission of infection from a bat to a human occurred not directly but through some intermediate link. But we do not yet know anything for sure about whether the virus had intermediate hosts, and if so, what animals it was. What is certain is this: in this ill-fated market in Wuhan, something was being sold that could become its intermediate reservoir. Seafood was mostly sold there, but there were also live animals and mammals.
There was also some information that it was transmitted from mice to snakes, and then to a human.
Yes, there were preliminary assumptions that the intermediate host could be a snake, but they have not been confirmed. The snakes probably had nothing to do with it. Moreover, in modern biology, there is no confirmed evidence that coronaviruses can be transmitted steadily among cold-blooded animals, which reptiles are.
“The virus can be transmitted at a time when the first symptoms have not manifested yet”
What is known about this virus? At least, the symptoms are known: first, it causes symptoms of viral respiratory infection, then pneumonia quickly develops. Is that so?
As far as we know, something like this. But the required amount of very important information that is needed to accurately describe the mechanics of its action has not been accumulated yet. Most importantly, we do not know what proportion of patients are asymptomatic, many people infected do not come to the doctor, stay home and get well in a few days, as in the case of common cold. There are definitely such people, but we need to calculate their number. Scientists do not know yet for sure what time passes between infection and the appearance of the first symptoms, we do not know how long the infection lasts. We still don't know much. I think there will be much more information in the coming days.
What do we already know for sure?
At first, it was not obvious even that human-to-human transmission of the virus is possible. Now we know it for sure. Also, there has appeared information that it is possible to get infected from a person in whom the first symptoms have not manifested yet, and this is very important for epidemiologists to know. We also know the genetic sequence of the virus. Coronaviruses are generally well studied, but only a few mutations can greatly change their properties. The current virus is similar to atypical pneumonia, but some of its properties, such as mortality and contagiousness, may differ. And they are very difficult to measure in vitro — such things are observed and studied only in the population.
Coronaviruses are generally well studied, but only a few mutations can greatly change their properties. The current virus is similar to atypical pneumonia, but some of its properties, such as mortality and contagiousness, may differ
How does the virus behave in the body, how is it transmitted?
As with most other coronaviruses, the transmission occurs mainly through airborne droplets. What we are seeing now suggests that the transfer takes place with fairly close contacts. There is the concept of the epidemiological cluster: this is when viruses that are very similar or identical in their genetic sequence infect several people who are in close contact with each other. These are usually people within the same family or patients who infect healthcare workers. But how active the infection is, for example, in transport, is still unclear, but it seems that the proportion of such infections is much smaller.
“The coronavirus changes more slowly than the flu virus. It's good”
How quickly such virus mutates, is it possible to develop a vaccine against it with a stable effect?
This is a virus whose genetic material is RNA, not DNA like you and I have. There are also other viruses organised the same way — for example, the flu and HIV. They mutate very quickly. But the coronavirus changes more slowly than viruses of, for example, influenza or human immunodeficiency. This is, in principle, good because it gives chances that when a vaccine is developed it will stay working longer.
Did they develop something against SARS at the time, didn't they?
Yes, but this vaccine has not been perfected. It only reached the first stage of clinical testing. No further progress was made because the outbreak faded and everyone's priorities changed. I think it will be the same now if the outbreak fades just as quickly.
Between outbreaks, the motivation of pharmaceutical companies is not so great, it is much more important to make a vaccine against the usual seasonal flu, which kills tens of thousands of people every year. It also needs to be constantly updated, of course. With outbreaks of new, hitherto unknown infections, when we do not yet know how it will end — everything is much more unpredictable. And now we just don't know how it will end.
Between outbreaks, the motivation of pharmaceutical companies is not so great, it is much more important to make a vaccine against the usual seasonal flu, which kills tens of thousands of people every year. It also needs to be constantly updated, of course.
Is it possible to keep up with changes in the virus? How long does it take on average to develop a vaccine for a new type of infection?
In this situation, we need to follow not so much the change of the virus, since it, fortunately, changes slowly enough, but for the development of the outbreak — it needs to be localized. As for the vaccine, its creation will take several months. But it is not enough to develop it — then the tests will begin. And they can drag on for months and years. Of course, in an emergency, the process can be accelerated, and the vaccine (if there are hints that it is effective) will be used as soon as its safety is proven.
Are there antiviral drugs in principle, how available are they and how do they work? We are talking about those drugs that are really fighting the virus, not the immune system of the body.
Such drugs do exist — for example, anti-retroviral drugs against HIV. Some ready-made drugs are now being tested in China on coronavirus patients. It is good to use existing drugs, of course, because they have already passed clinical testings. This means that even if we don't know anything about their effectiveness relative to a specific strain of coronavirus, we know for sure that they are at least safe.
In principle, humanity already has a certain stock of tools that can be used in the fight against viruses. For example, monoclonal antibodies that have already proven themselves well in the Ebola situation. But all this cannot be automatically transferred to a new pathogen, it requires additional development and testing.
“The panic in 2009 was not because people were dying more but because it was a completely new virus”
How long does a virus with airborne transmission take to cover a large area? Is it time to hide in the bunker?
As you can see, it took two weeks to conquer China. In neighbouring countries, this can also happen quite quickly. The situation is alarming, but this is not an urgent reason to start panicking. For example, there was no way to stop the 2009 swine flu outbreak, and remember the fuss? Meanwhile, since then, this particular flu has caused a seasonal outbreak in our country, and the situation is perceived as a completely usual, seasonal flu. It affects a huge number of people every year, but only a small proportion of them die. Perhaps, the same situation will be recorded with the new coronavirus.
The panic was in 2009 not because more people were dying but because it was a completely new virus that could be very dangerous. Then that went well: it turned out that the danger of it is comparable to the usual seasonal flu, which had been before it. On the one hand, the number of deaths was huge, on the other — there were no more or not much more than every year on a global scale according to statistics.
For example, there was no way to stop the 2009 swine flu outbreak, and remember the fuss? Meanwhile, since then, this particular flu has caused a seasonal outbreak in our country, and the situation is perceived as a completely usual, seasonal flu
And now, according to statistics, there are more deaths than the average?
It's hard to say. I have already said above: we do not yet know how many cases go away easy and almost asymptomatic. We don't know how many people got sick, we don't see the denominator. But without this figure, we can't estimate the percentage of deaths.
Is it really necessary to completely close cities and borders now? How do they fight the spread of such viruses in principle, and are there any other examples from recent history?
China has issued unprecedented quarantine in recent history effectively restricting the movement of 60 million people. How effective this will be is anyone's guess.
Historically, quarantines helped to slow the spread of infection, they give the opportunity to buy time, but one hundred percent impenetrable quarantine does not exist. It can't be the only measure. It is important to use the full range of measures that epidemiologists have. Now cases are already appearing far outside of China. It is important to trace these cases, to track the history of contacts of people — for example, those who brought the virus to the United States, to localize the contacts as much as possible. But we must understand that it is impossible to completely exclude the transfer of the virus across the border in our time.
Quarantine is the extreme measure and not always completely effective, any quarantine sooner or later is broken through. At the same time, we must understand that this measure is very expensive — both in terms of human rights violations, and in terms of economics, and in terms of that people find themselves without any of the necessary resources.
Is there really a reason to talk about a serious biological threat?
It certainly is — any new infection must be considered a biological threat until proven harmless. The question is how serious it is. The rate at which the virus is spreading and the proportion of severe cases are not yet fully understood.
Now scientists and doctors are most afraid of the beginning of uncontrolled spread of the virus around the globe — especially in those countries where everything is not very good with medicine
“I am afraid that these assessments are underestimated”
Very scant and limited information is coming from China. At the same time, we know how closed this country is. Are there any indirect hints in these unprecedented actions of it that something very serious is going on and that they are not telling us something?
In those cases of diseases and deaths that we know about — “officially confirmed” — I think we can believe. In China, a complex multi-step system is in place to confirm that they are indeed associated with the coronavirus. I am more afraid that these assessments are underestimated. Because in the Chinese medical system, confirmed cases are those that have received reliable biological confirmation in laboratory test systems. And often the laboratory where this is confirmed is located tens or even hundreds of kilometres from the place where the affected is located. And this all causes delays in informing. Therefore, again, I am afraid that this may be an estimate from below because confirmed cases are not all cases that actually take place.
The situation is certainly serious. But so far, the coronavirus has claimed significantly fewer lives than the seasonal flu virus does every year. And if we manage to contain this outbreak, then the situation will remain the same.
Then why are epidemiologists all over the world so alarmed?
Now scientists and doctors are most afraid of the beginning of the uncontrolled spread of the virus around the globe — especially in those countries where everything is not very good with medicine. For example, quite a large passenger traffic is established from China to Africa, and this is a scenario that raises concerns. After all, in many African countries, the level of development of the healthcare system is very low.
Can we talk about a pandemic yet?
I don't think so. A pandemic is a more global problem when the infection is evenly distributed in many countries. It's too early to talk about this now — we can talk about an outbreak. A pandemic is when the WHO introduces an international emergency regime, but it has not yet been introduced.
We need to wait for the situation to develop. If the virus gets into the country, then surely recommendations from the ministry of healthcare will follow immediately
How do scientists study the spread of infections?
For this purpose, there are data and mathematical models that have been used for a long time. For example, there is an array of data about all flights that are made between all countries of the world. There are long-developed epidemiological mathematical models that tell us how viruses will spread in a so-called naive population that has not previously encountered this particular virus.
The problem is that all these models require knowledge of parameters: the rate of spread, the duration of the incubation period, the length of time after infection, and mortality. If you give the wrong parameters, the model will give you the wrong answer. As the parameters are refined, we will understand the situation better and better. And the model is not a fortune teller: it gives only a range of probabilities and describes various scenarios for the development of the situation. It is impossible to predict which of them will be implemented until it is implemented.