Donald Trump and Boris Johnson both wore masks in public recently.
By Helier Cheung, BBC News
In the past few days, both US President Donald Trump and UK Prime Minister Boris Johnson have been seen wearing masks in public for the first time.
It's a dramatic turnaround - Mr Trump previously mocked others for wearing masks, and suggested some might wear such personal protective equipment to show their disapproval of him, even after the US Centers for Disease Control recommended face coverings.
Meanwhile, the UK government was initially reluctant to advise the general public to wear face coverings, even as other countries in Europe did.
It introduced rules requiring people to wear face coverings on public transport in June, and now says people in England must wear face coverings in shops or face a fine.
Globally, many authorities - including the World Health Organization (WHO) - initially suggested that masks were not effective in preventing the spread of the coronavirus. However, they are now recommending face coverings in indoor spaces, and many governments have even made them mandatory. Read more >>