How deadly is the coronavirus? How much of the population has already been infected? How widespread is immunity? The models politicians are relying on to make radical decisions in the COVID-19 crisis aren’t always 100 percent reliable.
By Manfred Dworschak, Veronika Hackenbroch und René Pfister
It’s a large-scale experiment unlike any other: Eighty million people across Germany are trying to protect themselves from a virus, with tens of thousands of them already infected — a number that is increasing by the thousands each day.
Stage two, the shutdown of public life, has long since begun. Everyone is listening to science, hanging on every word from virologists and epidemiologists. The mantra: flatten the curve. If too many people get sick at once, they warn, there won’t be enough intensive care beds for the most severe cases.
But how many infections can be prevented by closing schools? To what extent does closing the borders help? No one can say for sure. The effectiveness of strict shelter-in-place rules, such as those put in place by Italy and Spain, is also entirely uncertain.
With a lack of concrete knowledge about the adversary, the only thing politicians can do in their haste is experiment. Over the next few weeks, the measures taken in the fight against the novel coronavirus and COVID-19 must be monitored and, if necessary, adjusted. But sooner or later, the question will arise as to how long extraordinary measures like this can be kept in place. And above all: What happens next?
In China, to be sure, the strict epidemic regime is now being carefully relaxed in the hope that the number of infections won’t begin to rise again immediately.
Optimists believe that COVID-19 can indeed be stopped by this initial response and that the virus can be kept under control over the long term with just a low number of infections.
A Protracted Battle?
Other researchers expect the battle to be more protracted. They fear the pandemic will flare up repeatedly despite all the measures taken.
But all forecasts are based on model calculations in which unknown factors are lurking. For example: How contagious is a person who is carrying the virus? How many infected people will actually get sick with it? How many of those who do fall ill will actually die?
Scientists rely on plausible values when making forecasts. Normally, they also indicate how likely it is that their values are inaccurate. But such margins for error aren’t particularly helpful to politicians at the moment because they have to make concrete decisions. And it currently appears that they are doing their best to prepare for the worst possible pandemic path.
A much-cited study, compiled by a team led by epidemiologist Neil Ferguson at Imperial College in London, supports their pessimism. Ferguson’s calculations suggest that the fight against the virus is likely to drag on for years in several grueling stages. The crisis won’t end, according to this view, until a vaccine is found.