A screen divides a cashier, left, and customer right, at a pay point in a Spar supermarket, in Johannesburg, Tuesday, March 24, 2020, the day after it was announced that South Africa will go into a nationwide lockdown for 21 days from Thursday to fight the spread of the new coronavirus. For most people the virus causes only mild or moderate symptoms . For others it can cause more severe illness, especially in older adults and people with existing health problems. (AP Photo/Denis Farrell)