Simulation Study Suggests SARS-CoV-2 Surveillance Sensitivity Hinges on Testing Rates

A team from the Netherlands, Switzerland, and the US considers relationships between SARS-CoV-2 surveillance success and factors ranging from COVID-19 testing rates and sampling approaches to SARS-CoV-2 sequencing proportions in low- and middle-income countries. As they report in Nature Genetics, the researchers recognize that SARS-CoV-2 test rates are declining around the world, with rates averaging some 27 tests per 100,000 people each day in low- or middle-income countries. Based on their simulations, they suggest that countries with test rates of roughly 100 tests per 100,000 people a day would be better poised to pick up new SARS-CoV-2 variants and achieve relatively reliable variant prevalence estimates. At the moment, they say "low testing rates and spatiotemporal biases delay time to detection of new variants by weeks to months and can lead to unreliable estimates of variant prevalence, even when the proportion of samples sequenced is increased."