EIn principle, it is possible to spread the new lung disease Covid-19 to slow down. You can stop the virus, prevent the accumulation of serious illnesses. China has demonstrated this to the world, in its cities of over a million, especially outside of the Hubei province. Scientists and politicians around the world are now grappling with the question of how the virus can be handled appropriately.
The research work of epidemiologists – the experts who analyze and calculate the spread of infectious diseases, among other things – is important for these decisions. One of them is Sebastian Funk, who leads a team at the Center for the Mathematical Modeling of Infectious Diseases at the London School of Hygiene & Tropical Medicine. The German is a specialist in dealing with statistics, mathematical formulas and computer simulations.
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Together with colleagues, Funk investigated a month ago whether and with what effort one could prevent the spread of the Sars-CoV-2 coronavirus. For the analysis carried out in Trade magazine “The Lancet” appeared, the researchers translated the peculiarities of the virus and human behavior into mathematical formulas and simulated the contagion chains and disease courses on the computer.
The London researchers have run through thousands of simulations, with ever-changing variables. Two are particularly important. First, how many people are infected on average? This number is called the R0 value, the Funk team expected values from 1.5 to 3.5. Secondly, it is important to know how many people are infected before they even feel sick and consider taking a test.
Both values are primarily in the biology of the virus – but the number of infections is by no means only natural. It can be reduced by testing all people with symptoms as quickly as possible and isolating the infected and all contacts if the results are positive. In many Funk simulations, the epidemic has been successfully stopped in this way – but only with considerable effort. According to the result, 70 to 80 percent of all contact persons of an infected person should be found very early.
Efforts are not in vain
In an early phase with only a few infected people, such a procedure is not difficult. Contact tracking was successful in January when a Chinese employee of Webasto in Bavaria infected 14 colleagues. And a few countries such as Singapore, Taiwan and South Korea seem to continue to master strict containment along this path.
In a number of other countries, including Germany, this opportunity seems to have passed. “In Europe, the containment phase is obviously over,” says Funk. And even if one could still track all infections in Germany, the infection pressure from neighboring countries would be too great at some point.
The virus is in the world. Its complete eradication, as was the case with the Sars lung disease in 2003, will hardly succeed. However, this does not mean that further efforts are in vain.
“Tracking individual contacts will soon no longer be an effective tool,” says Funk. Nevertheless, one has to do everything possible to slow down the spread. “The major concern in all countries is that hundreds of people need to be treated in the intensive care unit at once.”
A slower spread could not only save the hospitals from collapse. Soon there could be better treatment options and hopefully a vaccine in a year or two. Until then, all hope rests on the “non-pharmaceutical interventions” – measures such as the much-discussed school closings or in the absence of public meetings.
Here, too, the epidemiologists try to assess the effect. They not only use their computer models for this, but also analyze the past. In the winter of 1918/1919, 500,000 to 675,000 people died of Spanish flu in the United States alone – however, the epidemic was very different from city to city.
Lessons from the Spanish flu
That was partly because whether the cities introduced school closures and other measures early on – this was the result in 2007 both independently of each other an American study and a UK work. In Philadelphia, for example, the danger of the epidemic was first downplayed and public life was only restricted when the health system was overwhelmed by the number of sick people. In St. Louis, measures were initiated after the first cases occurred – schools, churches and all other places of assembly were closed.
In Philadelphia, more than 12,000 people have died of Spanish flu. With 0.7 percent of the population, the number of deaths across all waves of flu in the city was more than twice as high as in St. Louis.
“A large number of interventions, which were used early on, proved to be very effective in 1918,” said Richard Hatchett, head of the American study, commenting on the results of the analysis in 2007. “And that gives hope that they would prove similarly useful if there were another epidemic without an effective vaccine being available.”
Today Hatchett heads the Coalition for Epidemic Preparedness Innovations (CEPI) international vaccine initiative. In an interview, he described the new corona virus as the most terrifying disease that he has encountered so far.
“We know from the historical data that it is important to start the protective measures early,” says Sebastian Funk.
Does that mean you should close all schools immediately? You cannot answer this question without thinking about another question. It reads: How long would the country last?
“Closing the schools in Germany at the present time would only make sense if you are prepared to keep them closed for a long period of time, that is to say for months, or to close them again if the number of cases increases,” says Funk .
Important for the situation picture: Test as much as possible
Studies have shown about an investigation by Australian epidemiologists from February: “If you are willing to close schools for only two or three weeks, then it is better to wait until the epidemic has progressed – but before the peak of the number of cases,” says Funk. In order to determine the best time for this, one has to get a good picture of how many cases there are in the population – so test as much as possible.
The decision for or against school closings is complicated. They have proven their worth in fighting influenza pandemics. And from a recent investigation in Shenzhen we know that children are infected just as easily as adults. “But we are dealing with a completely new virus here,” says Funk. Different rules could apply here. Children who are infected with the new coronavirus usually develop weak symptoms. “The big question is whether children can still spread the disease,” says Funk. “If not, then school closings wouldn’t do much.”
“Schools are not the driving force”
“In China, schools were closed from the start of the epidemic, and that didn’t stop the spread,” says Bruce Aylward in one Interview with the reef portal portal. The WHO epidemiologist was recently in China for nine days as the head of a team of experts who took stock of the situation on site. “Later, the schools didn’t stay closed, not even in Singapore and Korea, because it was concluded that schools are not the driving force.”
So it is quite possible that school closures are not the best weapon against this virus. It may even be more important to keep the children away from their schoolmates and away from their grandparents in order to protect them from infection. Children hardly get sick when they catch the virus, but they can pass it on to their grandparents. And people over 65 are often particularly seriously ill if they have contracted the corona virus.
When schools are closed, not only children miss the school material, often a parent has to stay at home for childcare – and may then be missing at an important point. “All of these questions can not only be answered from the epidemiologist’s point of view, there are always economic and social aspects,” says Sebastian Funk.
Many of the theoretically possible protective measures weaken the economy and ultimately the health system. How many people find themselves in an emergency because of losing their job or income? How big is the psychological damage? How many doctors and nurses are missing in hospitals when their children are not allowed to go to school?
With all of this, there remains the question of what you aim for in the long term. Maximum braking with the greatest possible effort? Even in Wuhan, the first measures, such as decommissioning traffic and closing most public places, have not completely prevented new infections. This only succeeded when all people stayed in their apartments, shows a new one Study from Chinathat was put online by peers prior to peer review.
What will happen if the drastic measures are lifted again? “China will then face the same problem as other countries now – that new cases will be brought in from outside,” says Sebastian Funk.
The German virologist Christian Drosten now assumes that there could be a wave of infections in Germany that will not weaken even in the warm weather in summer. In a podcast by NDR He urges that the vulnerable sections of the population, i.e. people of retirement age or with previous illnesses, be protected from infection.
It depends on political decisions – and on private ones
Drosten also strongly advocates canceling events wherever possible. And if the authorities cannot bring themselves to do this, everyone should be prepared to give up. Attending concerts or soccer games. At meetings and parties that are unnecessary. It may not be an important meeting in the office. Of course, you can also get infected in the office – but if a colleague falls ill there, the contacts can be tracked quickly. How do you know who sang at the stadium next to you for two halves?
The more often and the longer many people meet, the closer they get to each other, the greater the risk that there will be more and more new infections. Because those who have infected themselves often only notice that the disease sets in after a few days, sometimes only after two weeks. But even before you feel the first scratch in your throat before the fever begins, you can pass the virus on to others. In Berlin, 16 people were infected who celebrated in the same bar for one night. Probably only one other guest – who felt fit enough to go out.
In the next few days and weeks, it will not only be a matter of political decisions. But also on very private ones. The behavior of every single person who thoroughly cleans his hands, keeps his distance and stays at home with the slightest sign of illness, instead of squeezing into the full subway – this is also a lesson from China.
Nothing really can be predicted at the moment, says Sebastian Funk. There is still hope that the virus will prove to be less dangerous than expected, even if it is waning given the situation in Italy and elsewhere. However, he dares to make a prediction: “I believe that we must prepare for fundamental changes in our lives in the coming months.”
Assistance: Wiebke Hollersen