COVID-19's new Omicron variant is airborne, adding challenges to limiting spread

Alberta's top doctor says Omicron is spreading through the air with far greater frequency than previous variants, prompting her to recommend upgraded masks.

Dr. Deena Hinshaw, Alberta's Chief Medical Officer of Health, said Tuesday far more recent cases are being linked to single events and airborne transmission.

The advice is being echoed amongst doctors across the country as provinces take steps to limit the impact of a fifth wave.

"A lot of the gaps that you see in the surgical mask, especially on the sides are plugged up with an N95 masks, they filter 95 per cent of particles," said Dr. Kashmir Pirzada, an emergency room physician and representative of medical advocacy group Masks4Canada. "So your chances of getting a viral load high enough to get an infection is a lot less.”

Recent projections from the BC COVID-19 Modelling Group predict Alberta could hit 6,000 cases per day by the first week of January under current conditions.

Alberta went from an average of 644 new cases over the past weekend, to 818 confirmed and probable on Monday, followed by 1,380 reported for Tuesday.

"Previously, we thought maybe like one-in-10, or one-in-20 people with COVID [were due to] airborne transmission, maybe that's now up to like 20 per cent, or 30 per cent of people with COVID," said Dr. Daniel Gregson, infectious disease specialist and associate professor of internal medicine at the Cumming School of Medicine. "It could be that that the viral load is higher. We don't have good evidence for that yet.

"So you can imagine jumping on an elevator where somebody has been there without a mask on, and they may have contaminated the air in that space."

Since the early days of the pandemic, masks were primarily meant to significantly reduce spread through droplets — the tiny drops of saliva and virus that hang in the air as people are speaking. Airborne virus lingers much longer, appearing to add to Omicron's highly contagious nature.

The province introduced some new measures Tuesday and has asked Albertans to limit their weekly contacts by half and to upgrade their masks if possible. Cloth masks and the standard disposable surgical mask, while better than nothing, are far less effective due to lower quality filtration and a generally loose fit.

However, finding retailers with supply of N95 masks is a challenge. Costco and Home Hardware stores are sold out in the Calgary area, as are many Superstore, London Drugs and Calgary Co-op locations, an issue some retailers report has been a longstanding problem.

Non-profit Masks4Canada has published a list of suppliers as well as a guide to fitting masks on its website.