Regular COVID-19 testing for groups most likely to spread the virus more efficient, cost-effective than random testing. Credit: Shutterstock

As COVID-19 infections begin to rise again, a novel testing strategy proposed by researchers at the University of Oxford at the start of the pandemic has become urgent once again.

The strategy aims to bring the virus’s reproduction number (R) down to below 1, by concentrating testing resources on particular groups in the population that are most likely to spread the infection to others, rather than testing the general population at random.

“Governments around the world are looking for a testing