COVID-19: Here’s what increased testing can tell us…

Yesterday, I started to explain why expanded testing won’t necessarily guide the way out of pandemic lockdowns.

But since it seems to be the topic on everyone’s tongues these days, I feel compelled to present some true and honest facts that you may not be getting anywhere else.

So, today, let’s talk a little more about why the available tests may not actually give us all the answers we’re hoping for. And then we’ll talk about what they can tell us…

The bumpy road to validation

 COVID-19 is a new virus, which means that most of the tests we have on hand aren’t actually validated by the Food and Drug Administration (FDA), even though they’ve been cleared for emergency use. And this isn’t merely due to a time issue, either. Because as I’ll explain, validation itself gets complicated.

For example, calculating a test’s specificity requires validating against samples that we know to be negative for SARS-CoV-2. The problem is how to acquire those samples, since many infected patients can be completely asymptomatic.

(In this case, “specificity” refers to the test’s ability to accurately identify patients without the disease—in other words, its true negative rate. A test’s “sensitivity,” on the other hand, refers to its ability to accurately identify patients with the disease, or its true positive rate.)

The solution here might be to use stored blood samples from before the pandemic hit. But that, too, comes with problems. Like the fact that we don’t know when other coronaviruses tend to circulate, so we can’t determine cross-reactivity. (Not to mention, we don’t know how long those antibodies hang around anyway.)

Nevertheless, we’ve had no choice but to forge ahead and hope for the best, despite these limitations. And the testing we have done has at least helped us to determine just how  lethal the disease really is… which, on the bright side, at least appears to be lower than we originally expected.

Shedding light on mortality rates

One study from Stanford researchers set out to estimate how much of the population in Santa Clara County, CA tested positive for COVID-19. (At the time, Santa Clara had the highest number of confirmed cases in Northern California—it also had the earliest known case in the country.)

Using blood from confirmed COVID-19 patients and pre-pandemic controls, the sensitivity of their test came in at 80 percent, and the specificity came in at 99.5 percent.

And here’s what it found: Among the 3,000 people they tested, 50 were positive for viral antibodies. (I won’t bore you with the details of the subsequent analysis, but in the end, the researchers estimated an overall disease prevalence of 2.8 percent.)

Using that figure, they estimated that anywhere between 48,000 and 81,000 people had contracted SARS-CoV-2 in Santa Clara—a number up to 80 times higher than the confirmed cases they had on record at the time.

This would suggest a fatality fate of just 0.2 percent or lower. But of course, these figures have been disputed by scientists, with different methods offering fatality rates closer to 0.5 percent.

New York State also tested for prevalence, performing antibody tests on grocery shoppers. Their estimates predicted a 20 percent prevalence rate—amounting to roughly 1.7 million New Yorkers—suggesting a mortality rate of 0.9 percent.

Sure, that’s still way higher than your typical flu virus. But as I’ve mentioned here before, it’s also much lower than we feared at the beginning of this pandemic.

So what does that mean for you? Well, as I’ve mentioned numerous times over the past few months, it’s important to know the facts. And the fact is, this pandemic is likely to go on for quite some time—and universal testing isn’t likely to change that. So the best thing you can do right now is to keep your immune system firing on all cylinders by leading a healthy lifestyle. (That includes adopting a healthy, balanced diet, engaging in daily moderate exercise, and getting a proper amount of sleep.) For more guidance, check out my Complete Guide for Year-Round Immunity. This comprehensive guide outlines all of my top immune health recommendations. To learn more, or to order yourself a copy today, click here now!

And be sure to tune back in later this week, because there’s still more I’d like to review with you on this complicated topic…

Source:

 “COVID-19: Why We Can’t Test Our Way Out of This.” Medscape Medical News, 05/06/2020. (medscape.com/viewarticle/929917)