On the UnHerd youtube channel, they interviewed "Swedish expert Prof. Johan Giesecke" who said (around 3 minutes in) that while there's science behind hand washing to prevent the spread of disease,
but the rest of them [measures] like border closures, school closures, social distancing there's almost no science behind most of these.
Giesecke seem to be fairly well-known, e.g. he has a WHO page which says "he was the first Chief Scientist of the European Centre for Disease Prevention and Control (ECDC)."
So is what he saying true, especially about social distancing?