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We are moving according to the realistic scenario for the development of the epidemic, but November will be critical. This was stated in an interview with “Telegraph” by BAS mathematician Prof. Nikolay Vitanov.
– Prof. Vitanov, so far your predictions about the development of the coronavirus epidemic in our country are coming true. You predicted that by the end of August we would reach 16,000 infected, and that is what happened. What do the analyzes at the end of September show?
– We have three scenarios for the development of the epidemic: the best, the most probable and the worst. I work this way because that is how I am a scientist in the West.
The United States has also begun to make its predictions. At the moment, we are moving according to the realistic scenario. In the worst case, the total number of infected people could reach 25,000 by the end of September, but I don’t think that will happen.
The good scenario predicts 20,000 at the end of the month, but it is also unlikely to materialize. So most likely we will exceed those twenty thousand and probably go to about 21,700 infected. The amount above 20,000 also depends on how many people will follow the measures and how many will not.
– Works with the total number of registered cases, not with the assets. Why?
– Because this total gives us an idea of the development of the epidemic and how many people are really affected. We take the number of infected people, which is updated every day in the Unified Information Portal, and we multiply it by 8. Because for every positive sample that we find, there are seven more that we cannot find.
So we capture these 17,435, multiply them by eight and get 139,480.
This is the actual number of people who have encountered the virus. They are about 2% of the Bulgarian population.
– And is it possible that this number changes and at some point we have to multiply by 5 or 10 instead of eight?
– It is possible, yes. At first the number was five and then it became eight. We calculated this with the help of our American colleagues who have supercomputer programs. And when they bet our data, they tell us what that number is. You can change. However, for it to grow, we must have a sharp increase in the number of infected.
– Do changes in the virus itself affect your calculations: the different strains in which COVID-19 becomes easier to spread or more aggressive?
– The basis of our success in prediction is that we do not care what happens to the virus as biology. If there are internal changes to the virus that make it more or less contagious, this will immediately show up in the statistics and our odds will change.
Because our model is designed to adapt to the latest data. And then the values will change automatically. So from a purely biological point of view, we are not interested in the virus, we are interested in the numbers that describe its spread.
– Many people calculate percentages based on the number of new cases registered per day in relation to the number of PCR tests performed. However, they also include already diagnosed cases, which are examined to determine if they still carry the virus …
– Yes, that’s why I’ve always been against this percentage calculation. There are many reasons. First of all, the tests are not done randomly, so the classic statistics are inapplicable. also
the number of samples is currently very large because healthy people go on vacation to Greece
and this pushes down the percentage of positive samples. And when they stop traveling, the percentage of positive samples will increase.
– Many calculations and forecasts are also made around the world. One of them is at the Research Institute of the University of Washington. According to his calculations, in January 2021 in Bulgaria deaths from coronavirus could reach 5,818. What is your opinion?
– It is dangerous to predict so much in the future. I say what our calculations are for a month ahead, because it is easier for people to accept them.
The bad option in which this calculation was made, foresees a very high growth of the infected. We take this 5800 and multiply it by 200.
If in January the number of infected exceeds one million, that is, the number of registered cases is 125,000 (one eighth of the total number of infected), the number of deaths will be the same. Such a thing is not expected and even in the worst case, I think their numbers are inflated.
I don’t think the cases will reach six figures by the end of the year. But from now on, the number is sure to increase, so I am very careful what I say so as not to be accused of instilling fear.
– Is the factor with the opening of schools included in your forecasts?
– Yes, there are such calculations. In fact, the effect of opening schools will not be felt immediately. The incubation period for this virus is relatively long.
The children will go to school on September 15 and before the end of the month, even if they become infected, there will be no events. Also in the first days of October, major changes are unlikely to occur, because most children handle it lightly, not knowing that they are infected. The problem is that they are carriers.
If the child infects an adult, it will also have an incubation period of 10 days. So in mid-October, the effect of the opening of schools is expected to be evident.
Here the main risk groups are two: one is teachers and the other is parents, grandparents. There is a third group of special risk and these are the adolescents of the upper classes.
Because rebellion is natural for the young. Vitanov says “wear masks”, the teenager says “you will tell me.” And their body is already developed, and unlike children, who are often just carriers, older students can get sick. Active athletes are also vulnerable.
“Why?”
– Because, as is known, this virus attacks the lungs. And if the body is used to high oxygen consumption, and suddenly oxygen is drastically reduced, this can lead to big problems.
– It sounds very logical, and at the same time the story of our first rocket Grigor Dimitrov about how hard the virus was infected, surprised most of the people, precisely because we accept that he is an athlete – young, healthy …
– Yes, it’s simple: the virus interrupts the flow of oxygen and Grigor Dimitrov, who needs a lot of oxygen, handles it harder than a man like me, who is in front of the computer all day and does not need much oxygen.
In the same way it can be explained why COVID-19 managed to beat the wrestling champion Nikolay Shterev. However, he is a great fighter who needs a lot of oxygen, and the virus disrupts him and his body cannot cope despite his immune system, which was probably very strong.
– You avoid the numbers, but if we go back to the students, what growth in patients can we expect?
– We will know at the end of October and in November. We have these forecasts, but I cannot say them. Society is very sensitive on these issues.
If you react in time and the situation is controlled, you can easily achieve a form of face-to-face training for Christmas,
which will save the school year, because at least there will be a quarter. According to the prescribed measures, when a case of contagion occurs in a class, that class is dissolved, and when there are many classes, the school closes. So this will be the most obvious indicator of the situation. When schools start to close, you know the situation is dire.
– According to world statistics, Bulgaria ranks 81st in the world in number of infected …
– If you look back, there are few countries whose population is larger than ours, which means that we are doing well. How we proceed is up to us. I really like to tell the Bulgarian “Don’t fuck around, fuck the virus”.
Because we screwed up once. At the beginning of June we had 6 infected per day. And then I realized that we had to be careful not to lose the carp, because then we had to go back to fishing it. A lot of people laughed at me then, but we still miss the tent and made a problem for ourselves. In June and July we reached 300 cases.
Then, in August, with the effort of the entire system and thanks to the holidays and vacations during which people dispersed, the epidemic subsided. Now our starting position for September is good, we have 100-150 cases, which is not much.
So as long as we don’t miss the carp, I don’t expect to go much further. It is even possible to fall further down.
– And when to expect the next peak?
It is already taking shape if you look at what is happening in Asia, especially in the Philippines and Indonesia. The spread will be from there in the direction of Europe and the United States, but it depends on how quickly it reaches us.
The second wave will probably come to us in the middle of autumn from Western Europe.
November is likely to be critical in terms of distribution.
– You mentioned the holidays as a factor for reducing the epidemic in August. Now, however, can we expect import cases of Bulgarians returning from abroad and what are the critical points?
– You are talking about the so-called long pass or transfer of the infection from one place to another. Spain is critical of the Bulgarians.
There are many Bulgarians there and it is possible that they will spread the infection from there and this will be overlooked. Furthermore, in these cases it is more difficult to find the contact persons.
Therefore, after the end of the Christmas season, I hope that more people will consciously follow the rules, which in Bulgaria have never been very strict.
Nobody forces us to send a text message when we go out, but simply to keep our distance, or to wear masks everywhere, but to put them on when we are in public places, especially indoors, such as stores and pharmacies.
It depends on our behavior which of the scenarios we will follow.
– What burden can our healthcare system bear?
– At the beginning of the epidemic, 300 infected people a day was a problem. Subsequently, the health system was strengthened and
now we can withstand two to three weeks for every 500 infected per day.
I don’t expect the healthcare system to collapse in September or October. The main problem is that although we stock up on materials, protective equipment, beds, what we cannot accumulate are specialists.
And they get infected and diminish. This is the great challenge for the system.
This is the:
- Born in 1965 in Veliko Tarnovo
- He graduated from the Faculty of Physics at the University of Sofia and defended his dissertation in Physics.
- He went to Germany, where he studied fluid mechanics, and in 1998 defended his second dissertation for the degree of Doctor of Science at the University of Bayreuth.
- He specializes in “Time Series Analysis” in Dresden.
- In 2001 he returned to Bulgaria and began working at the Institute of Mechanics of the Bulgarian Academy of Sciences, where he still works today.
- He earned a Ph.D. and later became a professor
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