STEVE INSKEEP, HOST:
What should we make of what the CDC said and then unsaid? On Friday, the Centers for Disease Control and Prevention published new guidance. It said the coronavirus is airborne. That does not refer to the little droplets that travel a few feet from an infected person. To scientists, airborne means the virus may travel considerable distances, and aerosol transmission might be one of the most common ways that it spreads. The guidance was up all weekend and then removed on Monday. The agency says this was a draft posted in error.
Dr. Ali Khan is here to talk with us about this. He's a former CDC official, now the dean of the College of Public Health at the University of Nebraska Medical Center in Omaha. He's on Skype. Good morning.
ALI KHAN: Good morning, Steve. Thank you.
INSKEEP: And welcome back to the program. Wasn't it already widely understood that there was airborne transmission?
KHAN: Yes, Steve, absolutely. So there's nothing new in this change in guidance that there's a minor role for airborne transmission, and we knew this from SARS coronavirus 1, and we now have additional data from this new SARS coronavirus 2. So the disease is predominantly large-particle aerosol. So that's why this is predominantly aerosol.
So this is somebody standing in front of you who's coughing, speaking, sneezing, singing, for example, as the major mode of transmission. Occasionally, we get this disease from contaminated surfaces. And then there's a minor role, again, for these small particle aerosols, which is what is referred as airborne transmission, and these are transmitted farther than six feet away, potentially around a corner, especially in poorly ventilated indoor spaces. And then, finally, there's a yet even more minor role, probably, for transmission by via feces. So nothing new here.
INSKEEP: Well, what do you make of this unremarkable guidance being published and then withdrawn?
KHAN: Confusing. So CDC's not perfect and certainly has made some mistakes this past year. But with due respect to the agency, it's hard to imagine that this is one of them, given the scrutiny that they've had in all of their messaging. And for example - so just last week, we saw a flip-flop from CDC on testing of asymptomatic persons. We saw documented proof of manipulation of CDC's official publication. So, you know, it's not hard to understand people questioning that these changes may be deliberate interference by the ministry of obfuscation and misdirection.
INSKEEP: Which, of course, is not an official government office, but I gather you're suggesting the Trump administration is not happy with what the CDC is saying and is encouraging it to change things.
KHAN: Well, we've seen the deliberate undermining of public health over the course of this outbreak for political purpose, and we have seen numerous examples now of deliberate change of guidance that's not evidence-based.
INSKEEP: Can we still trust what the CDC tells us, then?
KHAN: Unfortunately, it's becoming harder to trust what CDC tells us. And this is extremely unfortunate because trust is the most important thing we need during a pandemic, as we tell people that regardless of this minor role of aerosol transmission, we have the tools available to us today to stop this outbreak in its tracks with test, trace and isolate, and please do our part of wearing a mask, washing our hands and socially distancing. And this trust is going to be even more important as we tell people to roll up their sleeves and get vaccinated, hopefully sometime at the end of this year and into next year.
INSKEEP: I'm glad you mentioned things like masking. I want to know if the practical advice after all of this confusion is still basically the same so far as you see it - see people outdoors rather than indoors, six feet apart, wear a mask, that sort of thing.
KHAN: Correct. The guidance doesn't change. So there's lots of nice, sophisticated aerobiology studies now that look at what happens when you sneeze and cough and how far these particles go and whether there's virus riding along in them. But we know that if we wear our masks and we couple that with the public health strategy of testing, isolating and tracing people, that we can get this disease under control. And, actually, many countries have done so, and some have even eliminated it, like, you know, Taiwan and New Zealand and China.
INSKEEP: Dr. Ali Khan, University of Nebraska. Thanks.
KHAN: Thank you. Transcript provided by NPR, Copyright NPR.