Dr. Leigha Rock is the Dalhousie University co-lead on a national study examining occupational risks associated with SARS-CoV-2 infection rates, transmission risk, and immunity in dental schools across Canada. Photo: Dalhousie University Faculty of Dentistry

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Dental and dental hygiene students and staff continue to regularly attend Canadian college and university campuses during the pandemic, but little is known about the occupational risks they face working in university dental clinics, labs, and offices.

On Thursday, the federal COVID-19 Immunity Task Force (CITF) announced $1.4 million in funding to investigate infection rates, transmission risks, and immune system responses in this population.

“When we look nationally at what my colleagues are concerned about, it’s a profession that has been targeted as potentially being very, very high risk. That being said, we’re so far speaking anecdotally, and not seeing higher numbers within the profession,” Dalhousie University Faculty of Dentistry professor Dr. Leigha Rock said in an interview Friday.

“But speaking anecdotally is one thing and then actually systematically collecting the data is another, which is why we’re going to systematically collect data and then we can speak very accurately to this question.”

The nationwide study is being led by Dr. Paul Allison of McGill University’s Faculty of Dentistry. Investigators representing all 10 Canadian dental schools — including Dalhousie — are also participating. Researchers will recruit 800 dental and dental hygiene students and residents, faculty, and support staff from across Canada.

Every month for a year, participants will provide saliva samples testing for active SARS-CoV-2 (the virus that causes COVID-19) infections. They’ll also be required to complete a monthly questionnaire outlining things like what procedures they performed and what PPE they used.

“The monthly saliva samples will allow us to test for active SARS-CoV-2 infections among the participants,” Allison said in a media release. “Those testing positive for the virus, over the course of the study, will be asked for additional saliva samples and blood samples on which we will perform antibody tests to determine if they are showing signs of immunity to the SARS-CoV-2 virus.”

Rock is the Dalhousie University co-lead for the study alongside Dr. Mary McNally. She said the plan is to recruit 80 participants from Halifax. She expressed excitement about the saliva testing, noting it’s easier to collect than blood or nasopharyngeal swabs and also allows for sub analyses.

She described the new study as “particularly exciting” due to the fact it will involve collecting matched samples of the same people over a long period of time.

“We’re going to have the ability to explore these antibodies, cytokines, etc. before and after samples…possibly before infection and after infection if we have any of our participants who become ill with COVID,” she explained

“What is also super exciting is we have the ability to perhaps look at these same biomarkers before and after vaccine. That’s going to hold some potential answers for other professions as well.”

Rock said people in dental environments aren’t only working directly in the mouths of patients who can’t wear masks. They’re also frequently performing aerosol-generating procedures.

“So we’re using high speed hand pieces or other types of equipment that actually cause things like saliva and bacteria and viruses and all of those things that happen to be in all of our mouths to aerosolize or become fine particles,” she said.

“That is the nature of the job. But there are a lot of PPE and engineering controls that are put into place to minimize that risk, and what we want to see is, are those things working?”

Although they believe their controls are indeed working, Rock reiterated the evidence so far is mostly anecdotal. She recalled how when COVID-19 first emerged, she and her colleagues discussed infection prevention and control and wondered if their PPE was adequate.

They turned to existing academic literature looking for evidence to support their pandemic decision-making, but were surprised to find very little.

“We really need to get on top of this. We had said (at the time) isn’t it too bad that during SARS or during MERS, this data wasn’t collected because it would help inform our decision-making at this point,” Rock said.

“We realized that what’s happening is really one of the largest natural history experiments that’s unravelling before our eyes, and we’d be very remiss not to be collecting data as this is unfolding.”

In addition to informing infection control procedures in dental and other health care professions, Rock said the data gleaned from the study could also apply more broadly to Canadian university and college campuses.

“The results from this research study will further inform the effective infection control protocols in dental schools, and possibly more broadly to Canadian university and college campuses across the country,” Canada’s Chief Public Health Officer, Dr. Theresa Tam, said in a CITF media release.


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Yvette d'Entremont

Yvette d’Entremont is a bilingual (English/French) journalist and editor, covering the COVID-19 pandemic and health issues. Twitter @ydentremont

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