Covid-19 testing is a major public good

Washington

TO TRACK the presence of Sars-CoV-2, the virus that causes Covid-19, the United States is relying heavily on polymerase chain reaction (PCR) live virus testing at massive scale. In the most common version of this approach, samples - nasal swabs or saliva - are sent to relatively large laboratories, with the goal of returning results within 24-48 hours. Unfortunately, while some priority tests receive speedy turnaround, it now typically takes 7-22 days to get results across most of the country. For a fast-moving virus like Sars-CoV-2, which can progress from infection to final outcome (death or recovery) in as little as eight days, long delays mean that PCR virus testing is a waste of time and money. By the time you know the result, it is too late to do anything different.

For "surveillance testing" - an essential part of preventing outbreaks - two highly unequal worlds are emerging. Big companies and universities will pay top dollar to test all their staff at high frequency (once or twice a week, with quick results), while everyone else will effectively not be tested (because results obtained after more than three days are of negligible value). This arrangement is not only hugely unfair (in ways that will become increasingly visible); it will also contribute to repeated resurgence of the disease in the coming months.