Ford calls for national contact tracing plan to contain COVID-19

Doug Ford is calling for a national plan for contact tracing, the labour-intensive public health work that is required to keep COVID-19 under control when social distancing measures are lifted.

The premier said at a press conference Monday he had discussed the "absolutely critical" issue with Deputy Prime Minister Chrystia Freeland earlier in the day and intends to raise the issue with the other premiers later in the week.

"Right now, each individual province is doing it," Ford said at a press conference. "But we need a national plan, to work with the federal government, and all the provinces, the 10 provinces and three territories."

Ontario Chief Medical Officer of Health Dr. David Williams backed the call for a national plan, saying co-ordination between provinces will be particularly important when inter-provincial travel resumes and health authorities will want to know how contained COVID-19 is in other provinces.

Meanwhile, Williams also said that Ontario's capacity to do the contact tracing work without being overwhelmed by the number of new cases every day is one of the key metrics that will determine when he'll recommend lifting social distancing orders, allowing the resumption of economic and social life.

Easing social distancing will mean returning to the "containment strategy" Ontario used when the coronavirus first reached Ontario in early January, according to Williams.

Containment relies on contact tracing: workers with each of the province's 34 public health units interview people who test positive for COVID-19 to determine how they contracted the virus and who they may have spread it to — and then those people are tested and told to self-isolate, and are themselves monitored by public health.

Williams likened it to doing a "comprehensive full police investigation" of each case in order to ensure the virus isn't spreading out of control.

Public health units are doing that work across the province, but Williams has said the containment strategy was overwhelmed in mid-March, when an influx of people returning to Ontario from around the world brought with them 60 to 90 new cases a day.

The overwhelming of the public health system is reflected in the data from the province's Integrated Public Health Information System (iPHIS), which centralizes COVID-19 data collected from each public health unit in the province.

The chart to the right shows the number of new COVID-19 cases on the date which symptoms first appeared, and the information concerning how the virus was transmitted entered in iPHIS as of May 3. Yellow represents the cases where information is still pending — it either hasn't been determined by the contact tracing efforts of the local public health unit, or the public health unit hasn't entered it in iPHIS. Aqua is travel-related cases, blue is known contacts of confirmed cases, and red is "neither" — meaning a case of community spread with an unknown origin. (Click on the image to open an interactive version of the chart in fullscreen.)

The public health system remains overwhelmed.

Williams said Friday that the number of cases that are considered "pending" should be only 1 to 2 per cent overall, because public health units should be able to figure out quickly, in all cases, when the person was exposed. That would be easier now, when people are following social distancing rules and are rarely exposed to others, he said.

In recent days there have been around 400 new cases a day, about half of them in the community at large, the other half in institutions, according to Williams.

While the province has been increasing the capacity of public health units to do contact tracing, late last week Williams said the province needs the number of new daily cases in the community at large to drop to close to 100 before the contract tracing and containment efforts of public health units can keep up. That would need to happen before he would consider recommending the broad restrictions on work and social life be lifted.

According to the ministry of health, the province has increased funding to public health units to allow them to hire more staff and allowed them to redirect more of their staff to contract tracing work, and to make use of thousands of retired nurses and medical students who have volunteered to help with the work. It is also facilitating staffing with its Health Workforce Matching Portal.

Colin Furness, an epidemiologist and assistant professor at the Faculty of Information at the University of Toronto, said it's not surprising that Ontario's public health units were overwhelmed in March because the work is labour intensive and public health units have long been understaffed.

"Really, it's brutal," he said, "and because they're civil servants, they never talk about it."

Looking at QP Briefing's chart of the iPHIS data, he said there is likely no point in going back over the cases that still remain pending today and attempting to trace them, as people's memories get worse as time goes on, and most of the pending cases should be considered community spread. However, he agreed that contact tracing is crucial for controlling the spread of the coronavirus.

Determining both how someone likely contracted it and who they might have spread it to is essential from preventing a second wave when businesses, schools and child-care centres reopen, he said.

The number of pending case varies widely across the province, with more in the large public health units of the GTA. Toronto has had more than 5,000 cases, by far the most in the province, and about half remain pending. Ottawa and Peel similarly have high case loads and high numbers of pending cases.

The situation in Middlesex-London is different — as of Friday it had only 413 cases and more than 90 per cent were considered pending in the iPHIS system.

QP Briefing reached out to the health unit on Friday, and on Monday Associate Medical Officer of Health Alex Summers said his health unit has been keeping up with contact tracing — and has, in fact, traced all of its cases, including the transmission sources.

However, the health unit had not been entering them into the provincial iPHIS system in recent weeks because it has developed a "web-based secure platform" to record information gleaned through contact tracing. Several other public health units are now using it, and Summers said Middlesex-London is hoping to interface it directly with the province system, but that has not come to pass.

The manual entry of data into iPHIS is time consuming and the health unit had been avoiding it hoping not to duplicate the work, but began entering the data Friday.

Summers also said the new system the Middlesex-London Health Unit can track data beyond what the province is asking for, including the race and the occupation of positive cases. Other public units, including Toronto, are collecting race-based data to determine if racialized communities are disproportionately affected, as has been seen in the United States.

Occupation data is something Furness has been asking for to allow the province to be able to know more about how community transmission is occurring, and make orders that would curtail that kind of spread, he said.

Meanwhile, Ontario is looking at using other technologies to aid in contact tracing.

"Ontario is also exploring the use of apps to increase the volume of contact tracing in Ontario, which would help contain the spread of COVID-19 in our communities," Elliott's spokeswoman, Hayley Chazan, said in an email to QP Briefing. "As we do, we are looking at technology that has the ability to support our health care system well into the future, consistent with our Digital First for Health strategy. For example, this could include apps that have the ability to follow-up and send prompts to people suffering from chronic physical conditions. While access to data is important, we are committed to taking all measures to ensure patient privacy is always respected."

Last week, Alberta Premier Jason Kenney announced that his province is launching an app to aid in contact tracing called "ABTraceTogether." Albertans who choose to download it can have it running on their phones when they leave the house, and it will connect by Bluetooth with other phones also running the app, storing that information on the individual users' phones. When someone tests positive for COVID-19, Alberta Health Services will request the information from their app to see which other app users that person was in contact with, and contact them.

However, Furness warned that apps are not panacea or a replacement for a public health workforce and they risk creating panic by alerting to people of a brief interaction with a positive case that wouldn't lead to transmission, and could lead to privacy breaches.