As we continue to work our way through the COVID-19 pandemic, balancing protection and practicality continues to be a challenge. The desire to return to “normal(ish)” is completely understandable. However, “normal” is a long way away. It’s more a matter of what degree of “abnormal” we’re willing to tolerate (and for how long), and what degree of disease risk we’re willing to tolerate – the two are generally inversely related.
SARS-CoV-2 is a respiratory virus, and it’s becoming clearer and clearer that respiratory droplets are the main risk for transmission. Yet, as more businesses and facilities look to re-open, the focus still tends to be on sanitization of surfaces. Yes, cleaning and disinfection is important; however, it’s not the only (or even most important) preventative measure. Enhancing surface cleaning without taking precautions to prevent droplet spread (i.e. mask policy) is of limited benefit, and is more along the lines of “look, we’re doing something” versus actually doing something effective.
One challenge we face in designing control programs for this (and many other) pathogens is limited definitive information about the source of infections (aka source attribution). It’s impossible to say X% of infections come from this source or that source. What we can say is based on the biology of the virus, lab testing and the patterns of spread, fomites (inanimate objects) don’t seem to be a major concern. A recent commentary in The Lancet entitled “Exaggerated risk of transmission of COVID-19 by fomites” (Goldman 2020) provides a nice synopsis of the issues. The first paragraph sets the scene: “A clinically significant risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission by fomites (inanimate surfaces or objects) has been assumed on the basis of studies that have little resemblance to real-life scenarios.” The article’s a commentary, not a research study, so it’s personal opinion, but it’s a good read.
What’s the downside of excessive concern about fomites?
The concern is making sure people are focused on the right priorities. Cleaning and disinfection is useful. Cleaning and disinfection as the sole or main preventive approach is not good. It’s like saying I won’t worry about wearing a seatbelt, being sober or using headlights when driving at night because I make sure to check my tires before I leave. Yes, the latter is important, but it’s only going to offer a small degree of protection compared to the other items.
Yes, wash your hands regularly.
Yes, clean and disinfect common touch surfaces.
But no, you can’t stop there. Wear a mask.
Businesses that focus on sanitizing surfaces over physical distancing and mask use are doing little to stop the spread of this virus. Customers will like it because it doesn’t require them to do anything and things will feel normal, but it’s increasingly clear that masks are the key to controlling this virus.
For those of you interested in a more detailed read about masks and protection, there’s a recent modelling study of their potential effect (Fisman et al. 2020, Infectious Disease Modelling). Don’t let the equations in the methods scare you off, it’s an interesting and important paper. Here are some highlights:
- Even if masks don’t offer complete protection, widespread use can reduce the SARS-CoV-2 transmission rate. Importantly, in reasonable scenarios, it can reduce the reproduction rate (R0) to below 1, at which point the virus starts to die out, since the average infected person infects less than 1 other person.
- Mask use alone doesn’t replace other efforts. There’s no single magic bullet. However, masks are a cheap, easy and effective control tool (now that they are more widely available than they were at the beginning of the pandemic, when there were severe supply shortages).
- The lower the reproduction rate (R0) in the community, the less effective masks are, and less widespread use of masks can still be enough. However, if transmission in the community is not well controlled (e.g. lots of cases but no distancing or other restrictions) masks will not be enough.
- As the percentage of the population that uses masks drops, the overall protective effect drops. It can drop to the point that cases continue to increase. So, mask use has to be widespread (typically through mandatory masking), particularly when disease rates are high.
Their somewhat understated but important conclusion is:
In the absence of evidence of harms done by masking, and with even preliminary evidence that they could influence epidemic growth, we suggest that their more widespread use be considered by jurisdictions which have not yet advocated this intervention.
Normalizing mask use is the key. Mandatory masking does that. In Wellington-Dufferin-Guelph, it’s required. Compliance is pretty much 100%. People don’t have to feel conspicuous wearing a mask, and there’s no drama about who is or isn’t wearing a mask. It feels normal very quickly. I think I’ve seen one person in a grocery store in Guelph without a mask in the past few weeks. In contrast, I was at a grocery store out of town this weekend in an area where masking isn’t mandatory. No staff and probably <5% of customers wore masks. Mandatory masking rules are not meant to focus on penalties and enforcement. They’re meant to encourage everyone to act and to make wearing a mask the socially accepted approach. You don’t need a bylaw officer standing on the corner to enforce compliance – you need to make it feel normal to wear a mask.