Unfortunately, the latest data now shows that testing is falling across much of the U.S. According to Johns Hopkins University, the average number of COVID-19 tests conducted per 1,000 people declined in the past week in 30 states — more than half the country. Nationally, the average number of daily tests dropped by 8.75 percent during the same period, from 822,470 on July 29 to 750,517 on Aug. 4. (...)
The good news is that there might be a simple solution: new tests that prioritize speed over sensitivity.
Storms aside, the main reason U.S. testing is going down instead of up is because the type of testing we’re doing — PCR (polymerase chain reaction) — seems to have reached its limit. PCR tests are the gold standard for diagnosing COVID-19, and rightly so: They correctly identify more than 98 percent of positive cases.
But they’re also slow, and getting slower. As the virus spreads, more and more potentially exposed Americans are demanding tests, forcing overwhelmed U.S. labs to compete with other countries for the supplies required to process so many samples. Often, labs run out. As a result, crippling backlogs have been delaying test results for so long they’ve essentially become worthless. (...)
Americans seem to be getting the message. “Long wait times and long turnaround times means people are just giving up,” Dr. Ashish Jha, director of the Harvard Global Health Institute, tweeted Tuesday.
The collapse of U.S. testing has, in short, exposed its fatal flaw. Costly and cumbersome PCR tests are fine when an outbreak is relatively modest; in that situation, you can afford to invest in a slower, labor-intensive test that won’t miss any positive cases because you want to stop the virus from spreading before it’s too late.
But when it’s already too late — when more than 4.8 million infections have been reported and nearly 160,000 people have died — the PCR infrastructure can’t keep up.
That’s why experts such as Dr. Michael Mina, an assistant professor of epidemiology at both Harvard Medical School and the Harvard T.H. Chan School of Public Health, are suggesting we scrap it and start over.
“We need to change the whole script of what it means to test people,” Mina recently explained.
Imagine a $1, at-home, paper-based test that’s as easy to distribute and use as a pregnancy test. Imagine waking up in the morning, adding saliva or mucus to a tube of chemicals, waiting 15 minutes, dipping a paper strip in the tube and reading your results — instantly.
Now imagine every single person in America doing this every couple of days.
So-called rapid antigen tests aren’t science fiction. In fact, they already exist. Two such tests, made by BD and Quidel, have received emergency authorization from the Food and Drug Administration, though both still require instruments to run. (The governors of six states announced this week a joint bid to purchase a total of 3.5 million of these antigen tests.) Another $1 antigen test has been put to use in Senegal. And U.S. companies such as E25Bio and Sherlock Biosciences have developed at-home tests as cheap and easy as the one described above.
These are not the same thing as the antibody tests you might have heard of, which detect virus-fighting substances in the blood of people who were infected previously (and may therefore have immunity). Rapid antigen tests are meant to detect ongoing, active infections.
So why isn’t the U.S. government mass-producing antigen tests and distributing them freely to everyone? The major hurdle, so far, has been what news stories tend to describe as “accuracy.” But “sensitivity” is a better way to think about it.
Storms aside, the main reason U.S. testing is going down instead of up is because the type of testing we’re doing — PCR (polymerase chain reaction) — seems to have reached its limit. PCR tests are the gold standard for diagnosing COVID-19, and rightly so: They correctly identify more than 98 percent of positive cases.
But they’re also slow, and getting slower. As the virus spreads, more and more potentially exposed Americans are demanding tests, forcing overwhelmed U.S. labs to compete with other countries for the supplies required to process so many samples. Often, labs run out. As a result, crippling backlogs have been delaying test results for so long they’ve essentially become worthless. (...)Americans seem to be getting the message. “Long wait times and long turnaround times means people are just giving up,” Dr. Ashish Jha, director of the Harvard Global Health Institute, tweeted Tuesday.
The collapse of U.S. testing has, in short, exposed its fatal flaw. Costly and cumbersome PCR tests are fine when an outbreak is relatively modest; in that situation, you can afford to invest in a slower, labor-intensive test that won’t miss any positive cases because you want to stop the virus from spreading before it’s too late.
But when it’s already too late — when more than 4.8 million infections have been reported and nearly 160,000 people have died — the PCR infrastructure can’t keep up.
That’s why experts such as Dr. Michael Mina, an assistant professor of epidemiology at both Harvard Medical School and the Harvard T.H. Chan School of Public Health, are suggesting we scrap it and start over.
“We need to change the whole script of what it means to test people,” Mina recently explained.
Imagine a $1, at-home, paper-based test that’s as easy to distribute and use as a pregnancy test. Imagine waking up in the morning, adding saliva or mucus to a tube of chemicals, waiting 15 minutes, dipping a paper strip in the tube and reading your results — instantly.
Now imagine every single person in America doing this every couple of days.
So-called rapid antigen tests aren’t science fiction. In fact, they already exist. Two such tests, made by BD and Quidel, have received emergency authorization from the Food and Drug Administration, though both still require instruments to run. (The governors of six states announced this week a joint bid to purchase a total of 3.5 million of these antigen tests.) Another $1 antigen test has been put to use in Senegal. And U.S. companies such as E25Bio and Sherlock Biosciences have developed at-home tests as cheap and easy as the one described above.
These are not the same thing as the antibody tests you might have heard of, which detect virus-fighting substances in the blood of people who were infected previously (and may therefore have immunity). Rapid antigen tests are meant to detect ongoing, active infections.
So why isn’t the U.S. government mass-producing antigen tests and distributing them freely to everyone? The major hurdle, so far, has been what news stories tend to describe as “accuracy.” But “sensitivity” is a better way to think about it.
by Andrew Romano, Yahoo News | Read more:
Image: uncredited
[ed. See also: Fast, Less-Accurate Coronavirus Tests May Be Good Enough (NYT).]
