Covid-19: How the coronavirus that causes it spreads

A crowd is seen at a roadside stall near the Ayer Itam market in Penang on May 8 in this filepic. It is estimated that four out of five people who have Covid-19 may only have mild or no symptoms, which may result in them infecting other people unknowingly.

There is much that is known, but much more that is unknown about the SARS-CoV-2 virus, which causes Covid-19.

But we do know that this virus spreads easily.