In the early months of the pandemic, the prevailing scientific advice was that frequent handwashing would help stop the spread of Covid-19.
In a closed and poorly ventilated room, these aerosols can float and drift in the air for a long time, greatly increasing the risk of infection. Initially, the World Health Organization and many governments insisted that masks should only be used by caregivers, patients and their close relatives and not by the general public.
Against all expectations, the pandemic showed that it is possible to design new vaccines against an unprecedented disease, and then start administering them worldwide in less than a year.Just over a year after the start of the global vaccination campaign, around half of the planet's population is fully vaccinated against Covid-19, according to the University of Oxford's website Our World in Data.