[The Conversation Africa] Many countries in East Africa have turned to contact tracing and carrying out COVID-19 tests on thousands of individuals as a way of monitoring and trying to limit transmissions of the new coronavirus. In Rwanda, they have been investigating how they can scale up testing significantly. But instead of testing every person - which would require millions of tests - they have turned to a different strategy: pooled testing. Leon Mutesa explains to Moina Spooner, from The Conversation Africa, how this works.