Is coronavirus airborne or not? B.C.’s Dr. Henry lays out the science of COVID-19

VICTORIA (NEWS 1130) – As the world adapts to new rules under pandemic restrictions, there is still a debate over how the coronavirus travels in the air.

It’s not a new debate and it likely won’t be settled in black and white terms. If you want the simple answer you won’t get it from B.C. Provincial Health Officer Dr. Bonnie Henry.

She says scientists have been trying to nail down whether some viruses can remain in the air for long periods or travel long distances, for years.

“When we talk about something in the healthcare world as being ‘airborne transmitted,’ what we’re talking about are viruses that are in very small particles that can last in the air for many hours, often, and then can float in the air column and can be transmitted down the hallway or through the ventilation system, for example,” she explained.

“And the ones that we most commonly associated with that type of transmission are viruses like measles, smallpox was one that would be transmitted through the air, as well as bacterial infections like tuberculosis.”

Henry adds when we’re talking about viruses like COVID-19 and influenza, they’re primarily in “larger droplets” that are spread by close contact with an infected person and don’t tend to survive in small particles.

“There’s a range of size [of droplets] when somebody’s talking but we know that the amount of virus and the moisture the virus needs to stay alive is a bit more for some of these viruses like influenza and COVID,” she says.

Henry was responding to a question from The Canadian Press at her June 6 provincial update. She was asked to comment on an open letter from 239 scientists worldwide, asking the World Health Organization to change its recommendations on the airborne transmission of COVID-19.

Henry says that letter was likely trying “to foment a bit of controversy,” and says she agrees with the WHO.

“So in the fact that it’s transmitted through the air, I think we’re all on the same page about that. And the fact that it’s not transmitted long distances, in the air column, we’re all on the same page about that.”

The letter, dated July 6, appeals “to the medical community and to the relevant national and international bodies to recognize the potential for airborne spread of COVID-19.

“There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission,” the commentary, titled “It is Time to Address Airborne Transmission of COVID-19”, reads.

It adds studies have shown “beyond any reasonable doubt that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and pose a risk of exposure at distances beyond 1 to 2 m from an infected individual.”

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Henry says the WHO has been doing “an amazing job” at keeping up with COVID-19 and believes the WHO’s side isn’t being represented.

“COVID is only one of the latest viral infections in this case where we have these discussions,” Henry said Monday.

“Where the challenge comes is we know that there is a gradation of how droplets come out when somebody coughs, or sneezes, or talks and it is the smaller ones that can be breathed deep into the lungs and it’s the larger ones that are often deposited up in the back of the throat or in the top of the lungs.”

In terms of how the science informs policy, Henry says using precautions specific to each environment is the way to go.

So hand hygiene, and mask and eye protection is important indoors or if you’re close to people and if you’re working in health care or a care center extra layers of protection become more important.

Henry adds we’ve seen evidence that outbreaks, such as  those detected in meat processing plants, have been mitigated with the use of plexiglass screens and increased ventilation.

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