COVID-19: Plastic dividers widely ineffective or even counterproductive, Ontario expert says

At first, some businesses used shower curtains or a makeshift plastic tarp to divide customers from staff members.

Twenty months after the pandemic began, it is practically impossible to go into a restaurant, retail store, medical office, or other business without seeing protective plastic shields separating people.

Now, one of Ontario’s top advisors guiding the province’s pandemic response says the plastic dividers may not only be ineffective — they may be counterproductive to public safety.

“Science is evolving,” said Dr. Peter Jüni, scientific director of Ontario’s COVID-10 Science Advisory Table and professor of medicine and epidemiology at University of Toronto at St. Michael’s Hospital.

Jüni told Global News in an interview Thursday that the use of barriers in public spaces may be hurting the effort to reduce the spread of COVID-19.

“Where you see (them) in schools or restaurants, the plexiglass can impede ventilation and give people a wrong sense of security,” Jüni said.

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The view is shared by other experts.

“The fundamental problem with a barrier is that it offers (in some cases) not much protection … what a barrier can do is it makes for poor ventilation,” said Jeffrey Siegel, professor of civil and mineral engineering at the University of Toronto.

“This is the right advice: I’m glad Dr. Jüni and others are saying it. I think it’s been well known for a while that barriers can be an issue,” said Siegel.

Neither Siegel or Jüni oppose the use of barriers in direct, face-face customer-service environments.

However, they say the broader use of fixed plastic barriers in public places can inhibit ventilation that is designed to promote better air flow.

“There are plexiglass barriers that are absolutely okay: if you have a check-out counter at a coffee shop. Where it’s a problem (is) where you see (it) in schools or restaurants: there the plexiglass can impede ventilation and give people a wrong sense of security,” said Jüni.

“Use the plexiglass only in situations where it really makes sense.”

Siegel says while barriers can also be used to limit how many individuals occupy a given space at one time, too many barriers deployed incorrectly can be trouble.

“We’re starting to have some data and the data suggests that … in some cases barriers can be more harmful than helpful,” said Siegel.

The Canadian Federation of Independent Business told Global News that there should be more clarity on the barrier issue.

“Dating back to the first wave, industry guidelines recommended plexiglass barriers. Even now the regulations on reopening prescribe different uses depending on the presence of physical barriers,” said Ryan Mallough, senior director of provincial affairs for the CFIB.

“We understand if the thinking on this has changed; however, it needs to be explained clearly and business owners should be compensated for their investment,” Mallough said in a statement.

But Ontario’s chief medical officer of health, Dr. Kieran Moore, said Thursday the barriers still have value in combating COVID-19.

“Physical barriers like plexiglass do have a role to play in the hierarchy of controls that decrease the risk of transmission.”