New cases of COVID-19 worldwide from January 23, 2020 to April 15, 2021, by day

On April 15, 2021, there were 816,276 new cases of coronavirus (COVID-19) worldwide. The total number of deaths from COVID-19 has reached almost three million.

Life under lockdown

Lockdowns around the world have helped to slow the spread of new infections – restrictions include working from home, limiting public gatherings, and banning all non-essential travel. The number of new cases continues to fall, but there is understandable concern about relaxing guidelines too soon, especially while the virus is still circulating at a very high rate. Countries are being urged to continue widespread testing, and experts have warned that some measures, such as social distancing and the wearing of face masks in public, may stay in place for the foreseeable future.

Testing remains important

For many countries, widespread testing is an essential part of any plan to reopen society. Rapid diagnostic tests (RDT) are increasingly being used to detect infection in patients. One type of RDT analyzes a sample to look for antigens – molecules found on the SARS-CoV-2 coronavirus – but the more common type of RDT tests for the presence of antibodies. The detection of antibodies in a blood sample means the body has been exposed to the virus, and immune system cells have reacted by producing antibodies to fight it. Mass testing is a strategy used to quickly identify areas with high cases, making it easier to isolate groups and prevent the spread.