New modelling shows COVID-19 transmission under control, but risk of outbreaks remains high
OTTAWA -- One of Canada’s top doctors says modelling shows the transmission of the coronavirus is under control across the country, yet relaxation of public health protocols could lead to severe outbreaks.
Deputy Chief Public Health Officer Dr. Howard Njoo says data points to a steady decrease in both the number and severity of COVID-19 cases since the peak of the pandemic in Canada in late April.
One of the key indicators of this, Njoo says, is the "effective reproductive number" or the "RT" as it’s more commonly called.
"In order for the epidemic to die out, RT needs to remain consistently below one, meaning on average, each new case infects less than one other person. Nationally, the RT for Canada has been mostly below one for more than 10 weeks," he told reporters in Ottawa on Wednesday.
Dr. Njoo said it’s likely Canada will see that indicator fluctuate as local outbreaks continue in Ontario, Quebec and Alberta.
"I think we’ve done an excellent job. We’re now at a place in Canada that where most of the cases we’re finding are actually linked to a known source so I think in terms of a classic public health practice, local health authorities are able to get on top of cases," he said.
The data forecasts a slight rise in confirmed cases from about 106,000 to date to 111,260 by July 17, and a minor incline in deaths from around 8,700 to 8,900 by the same date.
Females have been hit harder, representing 56 per cent of positive cases, and the median age sits at around 49. As in the last modelling update delivered on June 29, transmission between older groups is on a steep downward trajectory while transmission between those aged 20-39 trails behind.
"The steepest decline was seen in those over 80 years of age, this provides some good news that cases are declining among those at risk of the most severe outcomes," said Njoo.
However, outbreaks at long-term care homes remain the greatest sources of virus spread, followed by hospitals and correctional facilities.
"We must stay alert and strengthen our response in areas where we continue to have cases in the community and where we have experienced new outbreaks," he said.
Among other priorities, health officials say this includes detecting and isolating cases, maintaining contact tracing and strong quarantine measures, and rapidly attending to outbreaks when they emerge.
"The sooner cases can be identified and isolated in the course of the illness, the fewer other people they might infect. Likewise when most or all of their contacts are identified early and placed into quarantine, fewer are likely to spread the infection to others if they do become ill."
Prime Minister Justin Trudeau set the stage for the modelling update during a COVID-19 briefing with reporters earlier in the day. There he reinforced that while overall cases of the coronavirus in Canada are declining, some communities remain vulnerable, namely those in long-term care facilities and working on farms.
"The situation is stabilizing in Canada, because Canadians did their part and followed public health instructions but we still have to be very careful, things can change quickly," Trudeau told reporters on Wednesday.
"We still have some hotspots in some parts of the country, including in long-term care facilities and agriculture work settings. So as we continue to gradually reopen the economy we have to remain vigilant," Trudeau said.
York Region Public Health in Ontario is investigating an outbreak at a local mushroom farm after being notified on June 27 of 30 new COVID-19 cases. The majority of recent coronavirus cases in Ontario have been reported in the Greater Toronto Area and on farms with high populations of migrant workers.
The latest epidemiology report shows 1,242 cases and four deaths among workers in agricultural settings as of July 7.
Ontario Premier Doug Ford and Trudeau have underlined their concern about this specific sector and demanded that Ontario farm owners establish better living conditions and safety protocols for their workers. After Mexico temporarily halted as many as 5,000 workers from coming to Canada, the two countries settled on a deal to improve inspections and testing.
Over the past 14 days, Ontario’s Peel region and Windsor-Essex County are among the communities with the highest rates of COVID-19.
MANDATORY FACE MASKS
Face masks also became mandatory in a number of Canadian cities this week, prompting backlash from some groups who say the rule infringes on their personal rights.
Njoo was asked about the challenges involved with implementing widespread public health guidelines and whether his team has learned any lessons from previous examples like mandating the use of seatbelts or promoting vaccinations.
"We need to examine why people may be hesitant to take up a certain behavior that certainly – based on the science and evidence – we in public health think would be a good thing to do," he said.
"Certainly health promotion, maybe advertising campaigns, increasing awareness, is certainly ideal in terms of getting the general public to take up what we call healthy behaviors."
LOOKING AHEAD TO THE FALL
Njoo said Canada is entering into a phase of "risk tolerance" whereby the country is trying to establish the right balance between upholding necessary health guidelines while understanding society must reopen.
"We will, I think in general, accept a certain level of activity and recognize that we will have cases coming forward but that it won’t be an overwhelming outbreak and we’ll be able to manage it within the health-care system."
When asked about the issue of child care and sending kids back to school in September – an issue being approached differently from province to province – Njoo said while there is certainly a level of threat as children can be carriers of the virus, there are other considerations.
"We know that for kids going to school is very important for their growth and development beyond just academic acquiring of knowledge," he said. "We recognize there are mental health impacts."
Beyond the impact on children, parents’ well-being is also a factor.
"We recognize that anything other than fulltime attendance has implications even for the parents," he said. "In the present time we’re looking at what the experience has been in provinces notably British Columbia and Quebec."