Brooks Fallis is a critical care physician and the former medical director and division head of critical care at the William Osler Health System.
It’s just like the flu. About 99 per cent of people are fine after infection. It does not spread in schools. It does not hurt children. The vaccine will end the pandemic. Herd immunity is nearly here. Only hospitalizations really matter.
All mainstream messages. All wrong.
The latest message? The new wave of COVID-19 cases driven by the Omicron variant might be mild. The truth is that SARS-CoV2 is a nasty virus, and we continue to underestimate it.
We have the tools to combat Omicron, but we currently lack the will. It’s time to hold politicians to account and demand a better response.
Vaccines have been working remarkably well and remain the best way to prevent severe disease. Every Canadian should take every dose they are eligible to receive, and Canada should also be working to vaccinate other countries around the world.
Despite vaccines, the arrival of Omicron is daunting for a few reasons: The new variant has greater immune evasion than other versions of the virus, population immunity from second doses is waning, the administration of third doses has been regrettably slow and our health care system is fragile and understaffed.
Most importantly, Omicron has an explosive rate of growth, with cases doubling every two to three days. Spread will be fast and extremely hard to control.
Three features of SARS-CoV2 transmission run counter to our inherent mental model of infections, but are vital to understand. First, there’s presymptomatic transmission, which refers to the ability of the virus to be spread by people who feel completely normal and have no idea they are sick. Without broad recognition of this aspect of transmission, we will always struggle to contain COVID-19.
Next, the airborne factor. The virus is primarily transmitted by breathing in small particles (aerosols) that float in the air like smoke after being exhaled by an infected person. Infectious aerosols accumulate in indoor, poorly ventilated spaces. The virus is not primarily spread by large respiratory particles from coughing and sneezing (droplets), unwashed hands (contact) or unsanitized objects or surfaces (fomites).
Finally, there’s overdispersion, a term that describes the tendency for roughly 80 per cent of future cases to come from only about 10 to 20 per cent of current cases. Some people minimally spread the virus while others exhale infectious aerosols like ash from an erupting volcano.
The combination of these three features drives superspreader events and infection clusters, which in turn drive the pandemic. Omicron is putting these processes into overdrive. Rather than watching cases rise exponentially, is it not preferable to make immediate changes in exchange for better pandemic control, preservation of the health care system, and avoidance of death and chronic disease?
Public health groups, including the World Health Organization, initially espoused the idea that COVID-19 spreads through droplets. They have since resisted educating the public about airborne transmission or meaningfully altering their guidance. Now that we know about the airborne threat, our long-term goal should be to upgrade ventilation and filtration in all indoor spaces.
But it is impossible to upgrade every building quickly. We need to risk-stratify these spaces by the types of activities performed there, the number of people present and the feasibility of continuous N95 respirator masking.
Indoor workplaces where close contact is unavoidable – such as factories, warehouses, meat-packing plants, long-term care homes and hospitals – should shift to continuous respirator mask use. Each workplace also needs to provide large “safe rooms” with upgraded ventilation and filtration, with enough space for distancing so that masks can be safely removed during breaks.
Upgrading ventilation and filtration should be done primarily in places where continuous masking is impossible (restaurants, bars, congregate living environments) or challenging (daycares, schools). Any indoor space where masks will be removed needs government-mandated ventilation standards, and government subsidies to help it meet those standards quickly.
Rapid testing should become standard immediately prior to entering any indoor space where masks will be removed, including restaurants, bars and in-home gatherings of different households. This would require governments to make massive volumes of rapid tests easily available, free of charge. In addition, regular screening through rapid testing three times weekly would help keep the virus out of schools, which are the most challenging infection-control environment.
Rapid tests can help find the most infectious presymptomatic people before they enter these places.
An aggressive approach to public education coupled with transmission reduction and a high vaccination rate is our best chance to combat Omicron. The point of these interventions is not to restrict personal freedoms. It’s to preserve them, and prevent lockdowns or heavier restrictions.
By stopping transmission before it happens, schools, hospitals and businesses could remain open and functional.
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