SoylentNews is people
SoylentNews
Testing half the population weekly with inexpensive, rapid-turnaround COVID-19 tests would drive the virus toward elimination within weeks—even if those tests are significantly less sensitive than gold-standard clinical tests, according to a new study published today by CU Boulder and Harvard University researchers.
Such a strategy could lead to "personalized stay-at-home orders" without shutting down restaurants, bars, retail stores and schools, the authors said.
"Our big picture finding is that, when it comes to public health, it's better to have a less sensitive test with results today than a more sensitive one with results tomorrow," said lead author Daniel Larremore, an assistant professor of computer science at CU Boulder. "Rather than telling everyone to stay home so you can be sure that one person who is sick doesn't spread it, we could give only the contagious people stay-at-home orders so everyone else can go about their lives."
[...] They then used mathematical modeling to forecast the impact of screening with different kinds of tests on three hypothetical scenarios: in 10,000 individuals; in a university-type setting of 20,000 people; and in a city of 8.4 million.
[...] When it came to curbing spread, they found that frequency and turnaround time are much more important than test sensitivity.
For instance, in one scenario in a large city, widespread twice-weekly testing with a rapid but less sensitive test reduced the degree of infectiousness, or R0 ("R naught"), of the virus by 80%. But twice-weekly testing with a more sensitive PCR (polymerase chain reaction) test, which takes up to 48 hours to return results, reduced infectiousness by only 58%. When the amount of testing was the same, the rapid test always reduced infectiousness better than the slower, more sensitive PCR test.
That's because about two-thirds of infected people have no symptoms and as they await their results, they continue to spread the virus.
"This paper is one of the first to show we should worry less about test sensitivity and, when it comes to public health, prioritize frequency and turnaround," said senior co-author Roy Parker, director of the BioFrontiers Institute and a Howard Hughes Medical Institute investigator.
Journal Reference:
Daniel B. Larremore, Bryan Wilder, Evan Lester, [et al]. Test sensitivity is secondary to frequency and turnaround time for COVID-19 screening. Science Advances, Nov. 20, 2020; DOI: 10.1126/sciadv.abd5393
(Score: 3, Informative) by Rich on Monday November 23 2020, @09:14AM (1 child)
If it works, there will basically be no spread. The dangerous spreading mostly occurs (according to C. Drosten, but cf new Chinese report) around asymptomatic infection days 4-5 and symptomatic days 6-7. After that, infectiousness drops off and is mostly gone by day 14. We can therefore assume that the high viral load that causes symptoms (body cleans out infected cells, maybe overreacts with cytokines) exists before symptoms in an asymptomatic state. If the vaccination avoids symptoms in all patients, it is a pretty safe assumption that the vaccine-induced antibodies don't cause the viral load to rise to dangerous levels in the first place. The same thing would hold for an anti-viral agent that catches the virus by its ACE2 affinity, or synthetic antibodies (but you'd need a huge lot of fast and sensitive testing to know when to apply those before it is too late, or administer them in advance). It would not hold for a medication that modulates the immune response in a way that it can clean up, but does not badly hurt the organism in the course.
(Score: 2) by RS3 on Monday November 23 2020, @02:06PM
Wow, that makes sense. A gem of useful information, thank you.
And of course, dovetail in the hygiene / habits of someone infected. At the start of the pandemic, medical experts talked about covering your mouth when coughing, especially using your elbow.
Best to quarantine, of course, but even then you can spread the germs onto everything in your environment, and possibly spread it depending if you live with people, or somehow come into contact, maybe mail / ship a package. A report came out some weeks ago that SARS-CoV-2 virus can survive on hard surfaces for up to 28 days, so even if infected person pretty much stops shedding, could still be carrier / spreader. I think, anyway, but maybe it's much lessened and almost negligible? Well, not negligible if someone could get infected from visiting someone who had COVID say 24 days prior.
Thanks again.