When it comes to managing a pandemic well, you have to have as much information as possible to be able to take the right decisions. This knowledge is provided by science. But social urgency comes up against the fact that, by design, science is slow: it has to be very convinced before reaching any conclusions, to make sure it is correct. This difference in pace has created moments of tension since the emergence of covid-19, regarding, for instance, the issue of how the virus is transmitted: despite the months that have passed, no agreement has yet been reached, and this complicates defining the measures that are most effective in preventing contagion.