Are One In Three People Infected With SARS-CoV-2 Asymptomatic?

Daniel Oran and Eric Topol from the Scripps Institute have done a massive review of multiple studies and have come to the following conclusion:

...At least one of three people infected with SARS-CoV-2, the virus that causes Covid-19, do not develop symptoms. That’s the conclusion of a review we just published in the Annals of Internal Medicine. It summarizes the results of 61 studies with more than 1.8 million people...


Why does this matter to Oran and Topal?

Two reasons...

First, they argue that focusing testing on those folks that are symptomatic likely misses the boat when it comes to population-based viral spread:

...Even though knowledge about asymptomatic infection has greatly evolved, tactics for combating the pandemic have not. It is now obvious that testing only those with symptoms, as was common early in the pandemic, is a mistake because it ignores the invisible legions of infected people who have no symptoms...


Second, they argue that failing to test the asymptomatic could actually make things worse once more arms receive their dose(s) of vaccine:

...The rollout of Covid-19 vaccines brings with it the risk of a new wave of asymptomatic infections. The two vaccines authorized by the Food and Drug Administration {from Pfizer and Moderna} have been proven to prevent illness, but not asymptomatic infection. Even after vaccination, the coronavirus may still temporarily take up residence in the lining of the respiratory tract, making it possible to infect others. Preliminary results from one vaccine trial seem encouraging, with an apparent two-thirds reduction in asymptomatic infection after the first dose. But many other studies are underway.


So what's the solution?

Oran and Topal suggest that we should go big with antigen testing widely applied and done repeatedly like, it turns out, has been successful at some American universities:

...What’s needed is a pivot to a different type of testing. Antigen tests, which look for a bit of coronavirus protein, cost just a few dollars each and can yield results in minutes. Like home pregnancy tests, they require minimal instruction. Antigen tests are ideal for spotting people who are infectious, rather than those who may be long past the infectious phase of Covid-19, or who harbor such low levels of the virus that they are unlikely to infect others.

Inexpensive rapid home tests would help infected people isolate themselves before they could spread the virus. Frequent testing — at least several times per week — is essential, as demonstrated by successful testing efforts at some universities, which have enabled students to return to campus...

Real food for thought, I reckon, as we race to get to vaccine-driven herd immunity before the variants catch us.

(more on the variant stuff tomorrow).

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This story caught my attention because a good friend, colleague and guitar player is getting ready to send his eldest kid to one of the American schools concerned...It was he that first mentioned the succcesses they've had with rigorous, multi-pronged testing...I presume, but stand ready to be corrected, that the same might be said of our local Lotuslandian film industry?

And, to take this further, Topal and Oran conclude that this issue is even worse when you consider the folks who are infectious but 'pre-symptomatic...The piece cited above in STAT News is really worth a read if you are interested but don't want to wade through their scientific paper.


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