Fortunately, technological solutions to the slow test problem may now be available. One option is antigen tests, which come back in an hour or so rather than a week. Another is saliva tests, which simply require someone to spit on a piece of paper. Saliva tests are much cheaper and can get results much faster than a typical nasal swab test. Antigen tests were first authorized by the FDA back in May, and saliva tests have just been authorized recently.
The concern about these tests is their accuracy. Both kinds of rapid tests are less accurate than the slow nasal swab tests, meaning that if you test negative, there’s a small but real chance you could still be infected. Saliva tests, for example, catch infections only about 90% of the time. People who test positive on an antigen or saliva test will still probably want to confirm their diagnosis with a slower traditional test.
But antigen and saliva tests can be extremely effective for contact tracing. Even 90% accuracy is good enough to identify the majority of people who have been exposed through personal contact.
Saliva tests’ very low cost could also make mass testing feasible. Essential workers and vulnerable populations such as the elderly could literally be tested every day, reducing the need for contact tracing and allowing virus outbreaks to be contained very quickly.
Finally, rapid tests will make it easier to do clinical trials for Covid-19 treatments. Treatments such as monoclonal antibodies have great promise as potential cures for coronavirus, and they could potentially be available earlier than a vaccine. But trials for these therapies have been held up by the slowness of U.S. testing; subjects must take the drug within just a few days of being infected, so if they can’t be tested in time, they’re ineligible. Rapid tests could potentially solve this problem, if regulatory agencies allow it.
If past behavior is any guide, the Trump administration is unlikely to roll out a national effort to make rapid testing widespread. But now that the FDA has authorized such tests, state governments and philanthropic organizations can still do their utmost to make them available to all Americans. There’s no better hope for stopping the virus this fall.
Noah Smith is a Bloomberg Opinion columnist. He was an assistant professor of finance at Stony Brook University, and he blogs at Noahpinion.