Against Covid-19, Imperfect Measures Do the Most Good
It is a basic instinct of infectious diseases clinicians and researchers to seek and prescribe prophylactics or treatments that are almost guaranteed to benefit the patients who entrust us with their care.
With Covid-19, this instinct can be counterproductive.
The new coronavirus travels through populations too quickly and unpredictably for us to wait to tackle it until we have devised nearly flawless solutions. The widespread implementation of imperfect prevention measures, therapies and vaccines may be the fastest way to get a handle on the crisis.
Even those communities in the United States that are faring relatively well against the virus right now are still dangerously close to a tipping point: Infection rates and deaths could shoot up again suddenly, as in this summer. But there is another possible tipping point, too, in the other direction.
With more comprehensive use of even moderately effective prevention and treatment strategies, cases of infection and deaths could decrease substantially within weeks. It would be safer then to reopen schools and relax physical distancing restrictions.
There are to using to detect coronavirus infections, even though those are less accurate than the standard polymerase chain reaction (P.C.R.) tests, which can return a positive result or long after a person has ceased to be infectious. The paper tests have a rapid turnaround time; if deployed , they could be an effective first-detection tool.
A mask, especially one made of cloth, is a primitive block against respiratory viruses, and in terms of efficacy it probably pales in comparison with , the gold standard of barriers for preventing infectious diseases. Measuring a mask’s effectiveness at the individual level — particularly in the real world where use is intermittent and imperfect, and where people wear various types of masks — is devilishly challenging.
But based on mathematical modeling, my research group found, as it described in (a paper not yet peer-reviewed), that a mask worn by an infected person that filtered only 50 percent of the virus that person exhaled would lower the chances of their transmitting the virus to someone else by 10-60 percent (depending on how much of the virus the infected person carried at the time). When an infected person and another person are both masked, the chance of a transmission decreases by 40-80 percent.
When these effects are extended to an entire population, the overall impact can be profound, and when deployed along with other measures, they could mean the difference between case numbers that suddenly skyrocket and the of . Since seem to be , even slightly better masking practices among people who cannot avoid situations that favor clusters of outbreaks — like extended time spent in crowded and poorly ventilated settings — could bring outsize benefits.
May 24th note: the information about this article is hidden for a class exercise, but will reappear in a week after students have time to do the exercise