To mask or not to mask…..
A study done by van Doremalen, et al, through NIAID (National Institute of Allergy and Infectious Diseases) published in NEJM in mid March which I briefly discussed on my previous blog on March 21st somehow answered that question incompletely. They found that infectious viruses could remain in the air for up to three hours, in experimental model. The WHO, US CDC have been advocating mitigation policies based on that experimental study which frankly led us to where we are right now. But another study published in mid June in PNAS (Proceedings of the National Academy of Sciences in the USA) by Zhang, et al showed that airborne transmission, especially from aerosolization from a person nearby, is highly virulent and represents the dominant route for the transmission of this thing. They analyzed the trend and mitigation measures in the 3 epicenters that time-Wuhan, Italy, and NYC-from late January to early May. Other mitigation measures, such as social distancing implemented everywhere, are insufficient by themselves in protecting the public. That PNAS study concluded that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop this thing.
Long story short: yes, there is still a lot of uncertainties in the viral transmission but overwhelming evidence based on epidemiological and real time experience suggests that this thing is indeed airborne, at least temporarily. Not the same as TB, Measles or Varicella. Definitely not the same as the Motaba virus when Colonel Sam Daniels (played by Dustin Hoffman in the movie Outbreak) realized that it mutated and became airborne. This is contrary to earlier experimental studies that led us, including this data-avid ID doctor, astray. So wear mask like there’s no tomorrow, and practice social distancing.
Yes, science could be tentative once in a while. Scientists can make mistakes and they sometimes do. But science indeed self corrects all the time.