(Washington) The adage that the best is the enemy of good is tragically illustrated in the inadequate COVID screening strategy – 15 in the United States, argue researchers who advocate the adoption of rapid tests for a dollar, imprecise but repeatable several times a week by the entire population.
Posted on August 3 2020 at 15 h 44
France Media Agency
Michael Mina, professor of epidemiology at Harvard, has been campaigning for weeks for what he called shoddy, “bad” or more colloquially “crappy” tests. The idea is to break away from the current model of high-precision molecular tests (PCR tests), which are still too rare in much of the United States, for which people often queue for hours, and wait. days, or even a week, for results.
He proposed that the United States Drug Agency (FDA) authorize the marketing of rapid tests, done at home from a strip of paper that would change color in a quarter of an hour for give the result, like a pregnancy test.
These tests have a low sensitivity, ie they miss a lot of positive cases and therefore give a lot of “false negatives”, but for Michael Mina and other experts, this strategy would be more effective in terms of public health since at the population level, the number of cases identified would be greater than at present.
These rapid tests are good on average at detecting people who shed a lot of viruses, that is, when they are very contagious, at the very beginning, while PCR tests are very sensitive and even detect low concentrations of the virus, which happens at the end of the illness, when people are hardly contagious anymore.
“We are so attached to high-end and expensive tests that we do not test anyone,” lamented Michael Mina recently in the podcast This Week in Virology. “Maybe we just need a null test. If it is so cheap that it can be used frequently, then it might detect 85% of people who are contagious, instead of less than 5% ” .
The director of the Harvard Global Health Institute, Ashish Jha, returned to the charge on Monday.
“These tests are not so bad,” he told reporters. “When you're very contagious, and you have a lot of viruses in your throat and elsewhere, the test improves a lot.” However, “from an epidemiological point of view, this is exactly the time when we want to detect people”.
Even if the rapid test misses half of the cases, it is likely that with two tests per week, it will eventually detect them.
Everyone recalled that in addition, the current system misses nine out of ten cases, since relatively few people are screened, according to estimates from the Centers for the Fight against Diseases.
The FDA has yet to clear any of these strip tests, which are said to cost between $ 1 and $ 5.
“I fear that our federal government is stuck in an insane thinking pattern for this pandemic”, regretted Ashish Jha.