Does concern raised over the sensitivity of testing mean that every statistic about COVID-19 is bogus? No, that's not true: A recent article raised important questions about the sensitivity of standard tests and whether a positive test is the same as saying someone is contagious. It's not. Many who test positive may be carrying insignificant amounts of the virus. But this doesn't mean that testing is useless -- and it certainly doesn't mean that all statistics related to the disease can't be believed. That's an illogical leap.
The claim appeared in an opinion piece (archived here) published by RT -- a Kremlin-controlled news agency -- on September 3, 2020. Under the headline, "Up to 90% of people who test positive for Covid barely carry any virus & are not contagious. Every stat about the disease is bogus," it opened:
It has been revealed that the standard tests being used in the US to diagnose Covid-19 cases are far too sensitive, with the vast majority of people marked down as being positive actually turning out to be negative.
Users on social media saw this title, description and thumbnail:
Up to 90% of people who test positive for Covid barely carry any virus & are not contagious. Every stat about the disease is bogus
It has been revealed that the standard tests being used in the US to diagnose Covid-19 cases are far too sensitive, with the vast majority of people marked down as being positive actually turning out to be negative.
The RT piece riffed off a recent New York Times article, titled "Your Coronavirus Test Is Positive. Maybe It Shouldn't Be." The Times article made the case that the usual tests may be identifying people as positive when they're, in fact, carrying insignificant amounts of the virus and are not likely to be contagious. It drew a distinction between a standard PCR test, which gives a yes-no answer to whether someone is infected, and a test that provides some estimate of the actual amount of virus present. Here's its explanation:
The PCR test amplifies genetic matter from the virus in cycles; the fewer cycles required, the greater the amount of virus, or viral load, in the sample. The greater the viral load, the more likely the patient is to be contagious.
This number of amplification cycles needed to find the virus, called the cycle threshold, is never included in the results sent to doctors and coronavirus patients, although it could tell them how infectious the patients are.
The Times went on to report on data that included cycle thresholds, from Massachusetts, New York and Nevada. Its review found that "up to 90 percent of people testing positive carried barely any virus." That's the statistic that the RT article ran with and, at least according to reporting by The Times, it's not wrong.
The RT story, however, misses an important caveat, which is that "not contagious" may mean "not contagious yet" in some cases. People who are newly infected may have low viral loads, but could become contagious as the disease progresses and their viral loads rise. The solution, according to an epidemiologist cited by The Times, is more frequent testing to see which way the viral load in a patient is evolving.
In contrast, the RT piece states:
What these findings bring is absolute assurance that the testing to this point has been an utter waste of time, and that not one statistic concerning this pandemic - from cases to deaths to infection rates - can be believed.
Obviously, that's not true. There is no "assurance" that testing has been futile -- that's an erroneous interpretation of The Times article. In fact, health experts generally agree that the opposite is true: Testing is critical to the COVID-19 response. Finally, even if we were to assume that testing has been useless, that wouldn't mean that all statistics related to the pandemic can't be believed. That's a leap too far.
NewsGuard, a company that uses trained journalist to rank the reliability of websites, describes rt.com as:
The website of RT America, a 24/7 TV news channel and Russian government disinformation and propaganda effort. RT was previously known as Russia Today.
According to NewsGuard the site does not maintain basic standards of accuracy and accountability. Read their full assessment here.
