A new report published in the Canadian Medical Association Journal has shown that it will need many more months of physical distancing, ramped-up testing, and contact tracing, quarantining, and workplace and community closures to handle outbreaks to keep the novel coronavirus at bay. The report indicated that it’s crucial to continue using intervention methods as we reopen the country. According to the report, two-thirds of Canadians will be infected with COVID-19 if there will be no public health interventions.
According to Aamir Fazil, they needed to have a two-year horizon for the models. Aamir is the Chief of Risk Integration Synthesis and Knowledge Section at the Public Health Agency of Canada. He added that they felt that a two-year window would allow if any potential spikes were occurring. Depending on what health measures Canada takes, the researchers used agent-based modeling to know what could occur over the next two years. The reports stated that this type of modeling applies computer simulations composed of “agents that can represent people, places and objects.”
The report further notes that agent-based models are mainly appropriate for studying the effectiveness of interventions. This is because they are highly dependent on community structure and population dynamics. They looked at the specific intervention methods from Feb. 7 to May 10, in creating a baseline representation of the Canadian response. That was the period when the strictest community lockdown measures first began to lift slowly. They modeled four scenarios to see how the transmission could continue based on preventive measures moving forward from May 11 to build on this information.
They revealed that 64.6% of Canadians would become infected with the virus, and public health measures have remarkable results. Also, 56.1% of Canadians would be infected if there was no physical distancing or other restrictions despite having baseline testing and contact tracing. There could be a drop in the attack rate to 41.6% if physical distancing were enhanced. Besides, the total attack rate plummeted to 0.4 with “enhanced case detection and contact tracing.”
They found that the attack rate would reduce to 0.2% by combining the detection and isolation of cases with physical distancing. Also, about 1,100 people would die per 100,000 people, which are in terms of the potential death toll, in the minimal control scenario. When applied to the entire Canadian population, this would result in more than 413,000 people. If we had no intervention methods moving forward, this was still 320 fewer deaths per 100,000 than there would be.
In other situations, only two people out of 100,000 would die when contact tracing and isolation were combined with physical distancing. They also revealed that the “only intervention able to extinguish the epidemic on its own was partial community closure” like the one applied during the strictest lockdown measures between Mar. 16 and May 10. However, they said it is “likely unrealistic for such a restrictive intervention models as it means this strategy would take 18 months.”
The researchers also stated that something that they would like to consider in the next iteration of the model is the issue of face masks. Nonetheless, the researchers found that closing schools assisted in reducing the spread of COVID-19 within those settings. However, closing schools did not have much effect in reducing the number of cases overall, whereas closing workplaces and “mixed-age venues markedly reduced attack rates.” In a statement, NG indicated that school closures will have a insignificant effect when combined with these interferences and would not be adequate to control the epidemic when there are high levels of community transmission combined with minimal public health interventions and low observance to physical distancing.
According to Fazil, a “layered approach” is going to be necessary as every month passes, and it is the most important takeaway from the models. He added that there is a nomagic solution that was going to sort of stamp out the epidemic. He confirmed that people have to maintain additional public health measures as they increase opening up workplaces. What he thinks needs to be maintained as much as possible is picking up contact tracing, increasing the ability to detect cases and physical distancing. He added that “reducing the number of contacts” that people have is a “critical, ongoing factor.”
The model doesn’t account for specific hotspots for transmission, such as long-term care facilities or health care workers, because it aggregates data from across Canada. They acknowledge that valuable consideration is public compliance with pandemic measures. There is a long way to go in the absence of a vaccine or other therapeutic breakthroughs. Besides, Ashleigh Tuite stated that health officials will have to carefully and strategically impose measures to control the transmission of the virus. Tuite is an epidemiologist at the University of Toronto, and Amy Greer, who holds a Canada Research Chair in population disease modeling at the University of Guelph.