I can't really speak to the individual measures that might have been put in place in different European places and whether they were effective. I do know that what we have been calling for is rapid antigen testing before people get onto flights so that travellers can have that additional degree of confidence.
What we have seen from the studies that have taken place so far is that there are a very small number of travellers who have been testing positive, less than 1%. What we have now is testing on international arrivals. It would be even better to have it prior to departure.
There are many different ways to design that. Obviously the best way would be to have a very accurate predeparture antigen test. There are other places that have combined a test several days prior to departure with a rapid test at the airport. There are different ways of doing it.