ROCHESTER, Minn. -- It was a high-stakes plot point in the 1995 feature-length motion picture "Outbreak."
With a deadly virus contained in a sealed hospital ward, an epidemiologist played by Dustin Hoffman was notified of a strange new case down the hall. No one could understand how the virus, believed to spread through close contact only, travelled that far.
The mystery was quickly resolved, however, as the doctor looked up to a ceiling vent above the sick man's bed.
It opened into an air shaft that travelled back to the isolation ward. He quietly utters the two words that followed in a state of resignation and alarm: "It's airborne."
So far, we have yet to hear a similar determination -- officially at least -- about COVID-19. Were we, many believe it would vastly complicate the way we set about reducing spread during the pandemic.
Less concern about plexiglass and a magical power to staying 6 feet away from others. More concern about opening windows, turning up air flow systems, and not entering closed spaces where someone was recently breathing hard.
Health officials accept that some COVID-19 transmission is through very small airborne droplets known as aerosols. Officially, however, COVID-19 is unlike chicken pox, measles or tuberculosis in that, "most infections are spread through close contact, not airborne transmission," according to the Centers for Disease Control.
There "is no evidence of efficient spread (i.e., routine, rapid spread) to people far away" according to the agency, "... or who enter a space hours after an infectious person was there."
The World Health Organization has recently made a different determination, that COVID-19 can travel in air shafts, even releasing an advisory on air flow systems and COVID. That guidance proposes a minimum ventilation rate per person for nonresidential indoor settings. "Understanding and controlling building ventilation," WHO officials write, "can ... prevent the virus that causes COVID-19 from spreading indoors."
Change does occur in official positions on a new virus. Recently, the CDC began to downplay the role of fomites (contaminated surfaces) in spreading COVID-19, for instance, stating that "the risk is considered to be low."
But that did not cause federal health officials to redirect their attention towards COVID-19 in the nation's HVAC systems. Instead, "at this time, there is no indication of a general community need to use special engineering controls," the CDC states, "such as those required to protect against airborne transmission of infections, like measles or tuberculosis, in the healthcare setting."
If health officials are still on the fence, a trio of recent papers suggest that waiting for authorities to recognize COVID-19 can travel and even linger in the air, and in quantities sufficient to spread illness, is no longer necessary.
They believe the facts on the ground have already done that.
Writing on Twitter, a Harvard scientist framed this new show of certainty in seven words, stating: "this is the week the dam burst."
This is the week the dam broke.#CovidIsAirborne@linseymarr @jljcolorado @DFisman @kprather88 @AndrewMIbrahim, Julian Tang, Yuguo Li, Stephanie Dancer, @trishgreenhalgh, @chipatucsd, @zeynep pic.twitter.com/IxQVtynigv— Joseph Allen (@j_g_allen) April 16, 2021
With "Ten Scientific Reasons in Support of SARS-CoV-2," an article in the British medical Journal, The Lancet, a coalition of American and British scientists pointed out that COVID-19 has been transmitted in superspreader events "that cannot be adequately explained by droplets or fomites" -- including choir concerts and adjacent hotel rooms.
The authors cited asymptomatic transmission from people who are not coughing or sneezing, and they highlighted the fact of viable virus in hospital air filters, as well as rooms and even a car previously occupied by infected persons. They pointed out that animals sharing air vents have given COVID-19 to each other.
Writing the next day in the medical journal JAMA, Harvard physicians cited the fact that "smaller aerosols can stay aloft for 30 minutes to hours and travel well beyond 6 feet." They too, concluded that "far-afield airborne transmission ... of SARS-CoV-2 is occuring."
This, in their view, meant that classrooms, retail shops, and homes if guests are visiting should strive towards 4 to 6 air changes in the room per hour, especially in rooms with ceilings below 12 feet.
That same week, an editorial in the journal BMJ cited "the need for added emphasis on ventilation," stating that "the tiniest suspended particles can remain airborne for hours, and these constitute an important route of transmission."
It's like studying parachutes
"I think most of us in the field who look at this say there's no question there's airborne transmission here," said Mayo Clinic vaccine expert Dr. Gregory Poland.
"The data or lack of data that people bring to the question is something akin to saying, 'how do you know you need a parachute, when no one has done any studies...'"
"How is it that one person who was asymptomatic infected 60 other people in a distanced choir practice?" he asks. "Airborne transmission. There are everywhere from very large droplets, to airborne droplets, so that whole range of droplet size is occuring. It's not one or the other, it's a continuum of size."
Poland says COVID-19 particles could attach to "a piece of dust, mucous, whatever it is, and be maintained in an air current for long period of time," but says "you need a certain number of viruses in order to get infected."
"Putting one virus in your nose is unlikely to result in anything. Putting a trillion viruses in your nose is likely to make you pretty sick. I can't tell you the in-between. We don't know where that cut-off is."
Poland believes there should be stricter standards for ventilation, but says "the problem is, that in most indoor environments, there's not a lot you can do. HVAC systems are expensive."
"Outside of labs and health care systems they are not designed for this ... We do recommend that if you are going to meet, do it outdoors. Anything you can do that will increase ventilation will decrease risk."
Poland points out that during the 1918 flu pandemic, school was held outdoors in the middle of the winter, before resigning himself to add that "I don't think we have the resilience, as a society, to take this seriously enough," to do it ourselves today.
"How do you have a half-million Americans die, 40,000 kids that don't have a parent anymore, and have spring break? Eliminate mask requirements? Lift restrictions? I mean, this stuff doesn't make sense. It defies any logic."