Whose coronavirus strategy worked best? Scientists hunt most effective policies

Scientists are scrambling to work out what effect specific measures, such as social distancing, have in slowing the spread of COVID-19.Credit: Ivan Romano/Getty Hong Kong seems to have given the world a lesson in how to effectively curb COVID-19. With a population of 7.5 million, it has reported just 4 deaths. Researchers studying Hong Kong's approach have already found that swift surveillance, quarantine and social-distancing measures, such as the use of face masks and school closures, helped to cut coronavirus transmission -- measured by the average number of people each infected person infects, or R -- to close to the critical level of 1 by early February. Working out the effectiveness of the unprecedented measures implemented worldwide to limit the spread of the coronavirus is now one of scientists' most pressing questions. Researchers hope that, ultimately, they will be able to accurately predict how adding and removing control measures affects transmission rates and infection numbers.