Changing safety protocols challenge employers

It’s been over 18 months since the COVID-19 virus first took hold and spread alarmingly around the globe. From the start, there was confusion and panic, and not a lot of information about the deadly disease. 

As a result, employers scrambled to find hand sanitizers and signage in an effort to improve workplace safety, and then started installing barriers such as plexiglass dividers and implementing mask-wearing policies. 

Now, 18 months later, the data has evolved. Which begs the question: Aside from encouraging vaccination, are employers still doing what’s needed to protect employees and customers? Or are they working on dated information and wasting resources? 

There are two things to remember: This is a virus that two years ago was unknown to science, so we all had to do a lot of learning, says Raymond Tellier, associate professor in the Department of Medicine at McGill University Health Centre (MUHC) in Montreal. 

“The second thing is that the virus has changed. And the Delta virus that we're dealing with now is remarkably different from the initial virus that we had to deal with. In a way, we were lucky not to have to face something as contagious as the Delta from the beginning; we had a little bit of a chance. But if you want a metaphor, this is a little bit like when you play chess, — you quickly discovered that your adversary is not cooperating with your plan.” 

And when we think about the difference between airborne and large droplet transmission, some of the things that that we had very firmly put in place really don't make sense. And at the same time, there's a whole bunch of new opportunities to make some changes, says Colin Furness, assistant professor at the Institute for Health Policy Management and Evaluation, Dalla Lana School of Public Health, at the University of Toronto.

“So, there's the state of things that we are still doing, and then there's some enlightened things that we are not yet doing.” 

For example, we now know that aerosols are dangerous, but we haven't actually adjusted best practices to accommodate that.  

“There's no question that's a concern,” he says.

Since the airborne transfer of exhaled aerosol droplets is now understood to be the primary mode of COVID-19 transmission, more emphasis should be placed on improving ventilation and filtration and encouraging mask use, rather than deep cleaning surfaces, installing cough or sneeze barriers, or enforcing strict distancing beyond three feet, says Martin Bazant, professor of chemical engineering and mathematics at the Massachusetts Institute of Technology.  

“These scientific findings have all been acknowledged by the CDC and WHO over the past year, but have not been communicated effectively to local policy makers.” 

Fixated on surface cleaning  

Having learned that the virus spreads predominantly via an airborne route, things like surface cleaning and constant disinfection may be helpful for other infectious diseases but are “very unimportant” for COVID-19, says Marissa Baker, program director of the Dept. of Environmental & Occupational Health Sciences at the University of Washington. 

“And if you have limited time and limited resources and your primary concern is COVID-19, then time and effort is better spent with other controls,” she says. “Maybe, for the sake of COVID, [it’s about] relaxing on some of the cleaning, but keeping in mind that it is protective against other infectious diseases, which typically take workers out as well.” 

We now know that contact transmission was overplayed at the beginning of the pandemic, and while it probably happens, it's not the dominant route, says Tellier. 

“This mode of transmission has been overplayed. And there have been also some excesses that have been done in this, such as excessive decontamination of surfaces with very powerful disinfectant that may have in large amounts some toxic side effect as well…. This is a virus that's relatively fragile, and usual soap and detergent are quite sufficient to clean surfaces and disinfect and inactivate the infectivity of these viruses.” 

Part of the problem is that earlier research didn’t provide an accurate picture of the risks of surfaces. For example, the conditions used for some studies were artificial, says Emanuel Goldman, professor of microbiology, biochemistry and molecular genetics at the New Jersey Medical School. 

“They controlled temperature and humidity to be at the optimum [level] for the virus. And in the real world, that's a variable temperature, humidity. One study from Australia that made headlines all over the world kept the virus in the dark, and the virus is killed by mites. And that same study added a protein to the virus deposit called bovine serum albumin, that's a cow protein. And it was already published that that protein protects the virus.” 

Plus, viruses on a surface still have to reach a person’s lungs, and that’s not easy, he says. One study found a 10 per cent transfer rate of the virus from a surface to the fingers, meaning that 90 per cent of the virus is gone.  

“You still have to touch your nose, mouth or eyes with live virus to self-inoculate.” 

The big problem is it's really hard to measure that risk, says Furness. 

“The idea that at the grocery store, for example, the moving rubber mats that you put your groceries on — the whole idea [that] all has to be disinfected, or that you can't bring your own shopping bags in — those sorts of rules are excessive.” 

Cleaning the handles on the grocery carts, however, may not save a person from COVID but it’s going to help with other diseases, he says. 

“It's one of those things where I think we should deemphasize it, but I wouldn't actually recommend that we stop doing it.” 

Plexiglass dividers 

Another area that has come under greater scrutiny is the use of plexiglass shields, which were erected when it was thought that large droplets were predominant, but they are not so good against the aerosol, because aerosol can follow air currents that go around them, says Tellier. 

“Depending on the particular geometry of the room where you are or [where] you put them, and the ventilation system that you have, there are some setups in which these plexiglass shields can form some sort of wind tunnel that will concentrate aerosol in some areas. So, in some setting, they might increase the risk of aerosol contact.” 

When you're dealing with an airborne disease where the particles are very light, and they can diffuse, those barriers really don't offer much protection, says Baker. 

“In some instances, if they're blocking existing ventilation, they can create more of a problem, they can cause there to be a buildup right behind them. So, people actually could be more exposed.” 

If for example there’s a booth where a worker is completely sealed in except for a microphone, that could be valuable, because it’s fully blocking where the particles can go, she says. 

“In some sense, yes, they are providing a false sense of protection. But at the same time… we've come to associate those with a place that is trying to protect people. And so, it's kind of a visual cue that this workplace is taking steps to keep their workers safe.” 

In studying the difference in infection rates between bus drivers, streetcar drivers and subway drivers, Furness found that streetcar and subway drivers were in their own compartment with different air, which is great. Bus drivers, however, didn’t have the full shield of plexiglass, so they were sharing more air. 

“Bus drivers get sick, or have been getting sick, in the TTC at a much higher rate than streetcar or subway drivers… I'm not saying we've got to rip Plexiglas out as fast as we can. But we're relying on it and we're placing our faith in it. And we shouldn't, because when you're sharing air, you're sharing air.” 

The same could be said for grocery store workers who have a very dangerous job, he says, as they're not in a bubble at all, so they're sharing air. “That's concerning to me.” 

Mask mandates 

Masks fulfill two functions. For one, the wearer will not be expelling large droplets and will be protected against large droplets, especially within two metres of distance as large droplets fall on the ground at a relatively short distance, says Tellier. 

“Wearing a mask continues to be a very good idea because as it turns out, if you wear a mask, the amount of virus or virus particle that you will release in the room is going to be considerably reduced — but it is not zero. Second, wearing a mask will protect you considerably against smaller aerosols because the self-rating capacity of a mask is surprisingly good, even down to a few microns.”  

COVID is so much more contagious compared to the SARS virus because COVID is contagious during the incubation period of the disease, before symptoms appear, he says. 

“So, you want to ask people wearing masks both to lower your contiguity and to be protected from other people who will be contagious. So, if everybody wears a mask, it has a proven, protective effect.” 

Masking indoors remains a very important control, particularly high-quality masks with at least three layers that are tight fitting around the face, says Baker. But people need to be aware of when they might need to change their mask or take a break from their mask.  

“It’s important that workplaces have places and opportunities for people to take breaks from their masks,” she says. “If you give people the opportunity to take off their masks and relax, then [during] the time that they have it on, they're more likely to wear it properly, because they know that it's only for an amount of time... That is something that I think is helpful to keeping people safe: to keep the mass compliance high.” 

“What we don't want is people taking breaks in bathrooms; that’s a close, indoor environment. And we have seen evidence that the virus can linger in those spaces.” 

While single- or double-layer cloth masks are helpful, we can do better, says Baker. 

“Some of the more protective KN95 or even those pleated surgical masks can provide more protection. And those are things that workplaces can buy and distribute and expect people to use.” 

In 2020, the kind of mask people were wearing didn't seem to matter very much, but as COVID gets more contagious, it's going to become more important for people to wear N95 or KN95 masks, when they have a lot of exposure to the public, says Furness. 

“It would be helpful to enforce masks that properly cover the nose and have a wire over the nose that helps shape the mask [so people] don't have a giant gap over the nose. I've seen far too many nostrils over the last year and a half.” 

If it's a cloth mask, there should be three layers, with a propylene layer in the middle and cotton on the outside. It should also have a large surface area, he says. 

“Masks for some people seem to have gotten smaller... But the smaller the mask, the harder it is to breathe and the worse the fit is. You actually want a generous-sized mask.” 

Another area of concerns is elevators, with people often taking their masks off if they’re alone, says Furness. 

“That person has just filled that small box with aerosols and put the mask back on and not thought that they've done anything wrong at all… Elevators don't necessarily have great air circulation. So that to me is really concerning.” 

Ventilation, filtration advantages 

One of the final areas that has gotten more attention, with good reason, is air quality indoors, putting ventilation and filtration in the spotlight.  

“In general, you want to be bringing in as much fresh air as possible, whether that's from opening a window or from setting your mechanical ventilation to bringing in more outside air. That's important,” says Baker. 

You want to also be filtering that air to the extent you're able, whether that's through upgraded filters on your mechanical ventilation system, or a size appropriate HEPA filter. 

“Anything you can do to get more outside air into the space and to filter the air that's in the space, that's going to be valuable,” she says, but filtering systems are also not one size fits all. 

“If you're talking about a portable HEPA unit, those are going to be most effective in a smaller space. You want a unit that is sized appropriately for the space, and you don't want one that's going to be too loud and introduce other kinds of noise exposure. And you're going to want to make sure you have one that doesn't produce ozone, which again, is another exposure.” 

Ventilation is critical, and while there are other methods such as ultraviolet light to kill the virus, they can’t be shone directly on people because of the risk of skin cancer, says Goldman. 

“[Even] if you treat a room with ultraviolet light when nobody's in it, you still have the problem of someone who's breathing it after.”  

When it comes to the workplace, ventilation has not been well understood because of issues around the data, says Furness. Take, for example, airplanes. While they do have excellent filtration, with air coming in through the ceiling and out through the floor, and six or eight air changes per hour, they often shut their circulation systems off when they’re on the runway to stop exhaust fumes from being sucked into the cabin. 

“But as soon as you do that, your safety is out the window.” 

Plus, there is the issue of meal times, when everyone whips off their mask and starts chatting, he says. 

“[If] the person next to you has COVID and you're inhaling their aerosol, the air filtration system has nothing to say about it. So, you're breathing in directly air from what's been exhaled by your neighbours. So that's a problem.” 

Air flight crews purportedly have high rates of COVID, but airlines are not required to report the numbers, says Furness. There's no federal agency that collects this data and provincial agencies don't have the standing to force airlines to disclose.  

“They're getting sick, there's no question… And that tells me that we have a big problem… that lack of honesty, the lack of disclosure, the lack of transparency — that's a safety problem too.” 

A big challenge is that the data collection is really poor. It’s the same for restaurants, he says. 

“Some restaurants are good at collecting contact, tracing data, but most don't, and how good is their record keeping? So, in 2020, the argument to reopen indoor dining was that only one per cent of all COVID cases are attributable to restaurants — except that a whole ton of transmission happens there. You just can't measure it. And there's no systematic data collection around what proportion of servers are getting sick. So that's very, very problematic.”