Pandemics: Do we need an app for that?

Enlarge (credit: Purism)

Right now, with huge numbers of infected individuals and a limited testing capacity, the US has no way of knowing who's at risk for a SARS-CoV-2 infection. The ultimate goal of socially isolating, however, is to reduce the levels of infection so that we can do what's called contact tracing: figuring out everyone an infected individual has been in contact with and isolating and testing them. If implemented effectively, this will catch newly infected people before they become contagious, keeping the virus from spreading.

That process, however, relies on contact tracing being efficient and accurate enough to identify anyone at risk before they move on and infect multiple new people. A new study by a group of Oxford researchers suggests that SARS-CoV-2 is simply too infectious for this to work well. The team isn't without a solution, though: a smartphone app that caches contact information and alerts all contacts as soon as a positive test result happens.

Without a trace

Contact tracing is, in principle, really simple. Once an infected individual is identified, they're interviewed to ask where they've come into contact with other people for a while. In reality, it's a nightmare. People's memories are faulty, and it can be difficult to reconstruct everywhere they've been. And it's one thing if they know they visited a few friends or family members; it's something else if they rode a bus or stopped by a large store. Identifying who was even in the same place at that time can take days if not weeks.