When I last checked the Covid-19 trend line, it showed an encouraging flattening in the rate of growth of new cases in the US. China and South Korea had brought things under control much earlier and it looks like Hong Kong and Australia are also doing well. France, Italy, and Germany are definitely showing signs that they have passed the peak and slowing down the rate of growth.
But one of the concerns with the US data is that due to the massive incompetence of the Trump administration in rolling out testing and collecting data, testing is nowhere near a widespread as it should be.
From the beginning of the coronavirus crisis, lapses by the federal government have compromised efforts to detect the pathogen in patients and communities. A diagnostic test developed by the Centers for Disease Control and Prevention proved to be flawed. The F.D.A. failed to speed approval for commercial labs to make tests widely available. All of that means that the U.S. has been far behind in combating the virus.
Nationally, an average of 145,000 people have been tested for the virus each day over the past week, according to the Covid Tracking Project, which reported a total of nearly 3.1 million tests across the United States as of Tuesday night.
State health officials and medical providers around the country say they are unable to test as many people as they would like. Many of them say the biggest challenge is getting not the diagnostic tests themselves but the supplies to process them, including chemical reagents, swabs and pipettes. Manufacturers are facing a huge global demand as every country fights the pandemic, with many attempting the widest-scale testing they have ever undertaken.
So less that 1% of the country has been tested so far. It seems like one has to display symptoms of the disease to get tested, unless you are a wealthy person and/or a celebrity who seem to be able to get tested even in the absence of symptoms. This means that asymptomatic carriers of the virus are not showing up in the data, leading to undercounting.
Furthermore hospitals in the US are reporting that some patients are testing negative when their symptoms seem to clearly point to them having the disease, exacerbating the undercounting problem.
Tests turning up negative even when all signs point to COVID-19 has been a common experience in American hospitals over the past month, public health experts have told ProPublica. It’s unclear what proportion of these negative results are inaccurate — known as “false negatives” — and whether that’s due to some external factor, like bad sample collection, or because of an issue inherent in the tests’ design.
Neither the major test manufacturers, the U.S. Food and Drug Administration or the U.S. Centers for Disease Control and Prevention would say how common false negatives are. While the FDA requires test-makers to report any known instances of false negatives as a condition of granting them provisional approval, known as emergency use authorizations, no such reports are visible in a database the agency maintains for that purpose.
Nearly all tests have some degree of false negatives and false positives but in cases like this the former is more significant in terms of public health, because one wants to limit the number of carriers wandering around in public, unknowingly infecting others. Not knowing the rate of false negatives is concerning.
When the country starts to loosen its restrictions, it may be the case that you might need a certificate that you have tested negative to be able to go to your workplace, so that your co-workers feel comfortable around you. But if the tests have a high false negative rate, that might lead to a false sense of reassurance.