Contact tracing apps now cover nearly half of America. Its not too late to use one. – MIT Technology Review

Can these apps help? Early in the pandemic, apps that warn about potential covid-19 exposures were promoted as a way to contain transmission, and countries like Singapore and Australia launched their services in the spring (though early adopters had problems too). But without a coordinated national effort in the US, states created a patchwork of systems that launched at staggered times and didnt necessarily work across local borders. The first wave of US apps launched in August, months after those in other parts of the world, and in some areas they are arriving once widespread community transmission has already taken place. In Californiathe most populous state in the UScases are surging, for example, and most people are under a stay-at-home order.

At this point in the pandemic, experts say its too late for these apps to dramatically lower transmission on their own. But the software is still useful for keeping you personally safe and aware of when you should get tested. As vaccinations begin and cases go down again, experts say theyll be even more important.

On an individual level, in fact, its more important now than it was three months ago, because theres a lot more virus circulating in the community than there was three months ago, said Rajeev Venkayya, who helped write the USs first national strategy on pandemic preparedness in 2005.

Julie Samuels led the task force that developed New York states app. She puts it this way: In American society, people are really looking for a silver bulletfor the one thing that we can do to stop covid. The way to think about the app is that its one more layer of protection. If it keeps even one more person from getting covid, isnt that worth it?

Additional reporting by Lindsay Muscato

This story is part of the Pandemic Technology Project, supported by the Rockefeller Foundation.

For each app, we document who is producing it and where it is available. We also ask five questions, guided by principles put forward by the American Civil Liberties Union.

For each question, if we can answer yes , the app gets a star. If we cannot answer yeseither because the answer is negative or because it is unknownthe rating is left blank. Theres also a field for notes that can help put things in context.

In addition, we document the basic technology underlying the app. Heres an explanation of the key terms.

A public version of the underlying data is kept in a tab ofthis read-only spreadsheet. If you have an update, correction, or addition to the tracker, please email the relevant information to us at CTT@technologyreview.com.

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Contact tracing apps now cover nearly half of America. Its not too late to use one. - MIT Technology Review