Last updated on January 22, 2022

How the Virus spreads
Most COVID protections have been designed around that the assumption that, like influenza, this virus is mostly spread through comparatively large ballistic droplets produced by coughing or sneezing which tend to rapidly fall within one to two meters from the source patient. More transmissible airborne viruses like measles are spread by aerosols which are routinely emitted in the course of ordinary breathing and which are small and light enough to remain airborne much longer, travel beyond 2 metres and penetrate the gaps between masks and faces. It turns out the COVID viruses are transmitted via both droplets and aerosols. The risk of infection is directly proportional to viral concentration in the air being breathed. Virus-carrying aerosols are most concentrated at the source, diffusing and diluting with distance. Long-distance transmission is therefore rare in well-ventilated spaces.

How to Mask Effectively
Those characteristics suggest two basic strategies for preventing infection by people outside one’s trusted “bubble”: avoid close contact in poorly ventilated spaces and, whenever that’s not feasible, always wear well-fitted, quality masks. The gold standard for quality masks is N95 certification, which is defined as the capability to filter out 95% or more of particles/droplets with median diameters 0.3 micro-metres or larger. Such masks are constructed from multiple layers of finer fibres than simple cotton fabric. That said, the actual filtration capacity is far less if the mask is not sufficiently well fitted to block air flow through gaps between any of the mask edges and one’s skin. Preventing such flow requires both a high-quality, well-designed mask and carefully following the accompanying instructions. If detailed instructions have not been provided, the mask is likely not worth wearing. If you’re serious about the heightened risks inherent in today’s much more infectious variants and unknowingly infecting others, simple cotton masks (however attractive) no longer cut it.

N95 masks have recently become more available in Canada, especially the KN95s from China. Both appear to offer comparable filtrations. The KN95 standard includes actual human quality of fit testing whereas US NIOSH-certified 95’s meet more stringent breathability standards. If your favorite pharmacy is out of stock, you can order KN95s from and NIOSH 95’s from Avoid ordering any that do not explicitly state N95, because they probably won’t be. My most recent US order for 20 NIOSH N95s cost only C$2 per mask delivered (click here to view the detailed fitting instructions which were included with those masks). They last a long time.

Ignore uninformed naysayers, whether on social media or elsewhere. Masks have proven to be surprisingly effective. For example, Ontario, among Canada’s worst-afflicted provinces through much of the pandemic, experienced a much less severe Delta wave. What was different? It never lifted its third-wave indoor mask mandate, thereby limiting the fourth-wave spread of the Delta variant. Peru, a low-income country, was among the nations hardest hit by the second wave but nearly escaped the third. What it did differently was the simple, cheap expedient of requiring double-masking in all situations for which two-meter social distancing wasn’t possible. And then there’s Japan which after the departure of Olympic visitors became largely COVID-free thanks to a long cultural tradition of mask wearing whenever experiencing cold- and flu-like symptoms.

How to Maximize Vaccine Protection
It is equally important to recognize both the necessity of being vaccinated and the very real limits to the protection that it gives you. That requires understanding the important difference between protection against infection and protection against death or serious disease. One last-December UK government report found that protection against Omicron infection waned from 70% one week after a third-dose booster to only 45% after 10 weeks. That said, two and three doses of all the major vaccines appear to offering continuing protection against severe illness and death for at least six months. While “breakthrough” symptoms among vaccinated people are typically mild, to the point that infected persons may not even realize the need to be tested, they are in fact infectious and can therefore spread COVID to their families (especially unvaccinated children) and other close contacts. It’s therefore very important that we register for booster shots as soon as we become eligible. Thus far, only immunocompromised Canadians have been eligible for four doses.

The risk of breakthrough infections while socializing even in small groups is much higher than most of us realize. In my own circle, a best friend and her husband attended a pot-luck dinner gathering with five other couples that was intended to be outdoors but moved inside due to weather. All were fully vaccinated. The husband in one of those couples wasn’t feeling well so he stayed home while his wife attended. It turned out that he was COVID-infected and had already passed it on to his wife, who then infected half of those who attended. All had relatively mild symptoms and, thankfully, were informed in time to isolate before passing it on.

One moral of that story is to get tested immediately if you experience any cold- or flu-like symptoms or have been in close contact with others who may have been infected. Since most of us no longer qualify for PCR testing even if we’ve been exposed and are symptomatic, it would be wise to purchase a small supply of rapid antigen test kits so that you can self-test 48 hours after having been in any setting in which it wasn’t possible to maintain proper (2 metre) social distancing. In my experience, those tests are very easy to use.

Symptoms to be on the lookout for
Symptoms of COVID-19 can vary from person to person and in different age groups. They may take may take up to 14 days after exposure to appear. While full vaccination makes it very unlikely that you will come down with a severe, life-threatening case of COVID, it provides limited protection against Omicron infections and that protection declines significantly each month following your most recent dose. It’s important for your own protection and the people around you to get tested immediately if you experience one or more of the following symptoms: new or worsening cough, shortness of breath or difficulty breathing; temperature equal to or more than 38°C; feeling feverish; chills; fatigue or weakness; muscle or body aches; new loss of smell or taste; headache; abdominal pain; diarrhea and vomiting; and/or feeling very unwell.

If you test positive
Most people who experience or test positive with moderate symptoms and no serious pre-existing risk factors will normally be instructed to self-isolate. Be sure to meticulously follow those instructions. But don’t delay seeking further medical help should your symptoms not quickly diminish. This brief UK video provides useful guidance in that regard.