British Columbia’s health officials say people need to maintain public health measures and contact tracing needs to continue to help control the spread of COVID-19 in the province.
Dr. Bonnie Henry, the provincial health officer, and B.C. Health Minister Adrian Dix presented the latest COVID-19 epidemiological modelling on Tuesday, which shows as the province continues to reopen, B.C. is closer to a threshold where renewed growth of cases could occur.
According to Henry, an increase in cases is expected as people start to have more contacts.
However, she said to have epidemic control, physical distancing, self-isolation for those who feel sick, and a continued focus on hygiene measures are critical.
There also needs to continue to be contact tracing to ensure epidemic control when population-level restrictions are relaxed.
Henry said the province is in a fine balance between reopening and controlling the spread of COVID-19.
As of Tuesday, there are 13 new COVID-19 cases in the province, bringing the provincial total to 2,835. There has been one additional death in long-term care in the Vancouver Coastal Health region. The death toll is now at 170.
A total of 2,491 people have recovered. There are currently 16 people with COVID-19 in hospital (two more than June 22) and seven in intensive care.
There are no new cases in Island Health, which has had 131 cases since the pandemic began. One new case was announced on June 22.
There have also been 960 cases in Vancouver Coastal Health, 1,480 in Fraser Health, 199 in Interior Health and 65 in Northern Health.
Right now, there has not been a dramatic increase in cases, hospitalization or intensive care from COVID-19 as contacts have been done safely, Henry said. The modelling shows B.C. has risen to 65 per cent of pre-COVID interactions.
B.C.’s COVID-19 modelling showing the possibility of continued growth in the summer (BC government)
Higher rates of infectious contact lead to a more rapid rebound in new cases. (BC Government)
The modelling also shows that B.C.’s reproductive number — representing the number of people one case will transmit to — has dropped from 11 in March, to one.
The model showing the reproductive number dropping due to COVID-19 safety measures.
Data from Google shows British Columbians continue to increase movement as the province reopens.
Henry said the models are illustrative, but not predictive. Since multiple actions were put in place at the same time to reduce the spread of COVID-19, the reduction in cases cannot be attributed to one particular intervention.
“If we dramatically increase to 80 per cent, or go back to what was normal, we can expect to see a dramatic increase in cases, and that is what we want to avoid,” Henry said.
According to B.C.’s contact trace modelling scenarios, contact tracing needs to be complete and prompt to prevent sustained transmission.
With moderate physical distancing in place, at least 75 per cent of contacts need to be traced or isolated in two to three days. With weak social distancing, an increasing number of contacts need to be traced or isolated in a shorter time period.
Contact trace modelling scenarios (BC Government)
Contact trace modelling scenarios (BC government)
Henry said as the province has relaxed distancing measures, strong contact tracing in BC has provided a buffer against renewed growth of cases. She added that so far in in B.C., 97 to 99 per cent of contacts have been located within 48 hours.
But as the province further relaxes, Henry said the completeness and rapidity of contact tracing will be even more important for controlling transmission, in combination with self-isolation by sick individuals and strict hygiene practices.
Henry said old-fashioned contact tracing, not an app, is the primary tool that’s been helping public health officials find people who could be infected with COVID-19.
She said officials are accustomed to tracking people who could have come into contact with carriers of other diseases and COVID-19 is no different, except that 600 people have been focused on the task.
Henry said an app would be more useful for when people may have spread or contracted the illness in a large crowd of people.
Prime Minister Justin Trudeau has promoted a voluntary app called COVID Alert, which will be tested in Ontario before being rolled out across the country.
Henry also said Wednesday the B.C. Centre for Disease Control is working with other jurisdictions to develop a method to test wastewater for COVID-19 RNA sequences. So far, there have been no sequences found yet in wastewater samples, showing low level transmission, but it could be used as an early detection tool in wastewater communities.
Henry also talked about B.C.’s epidemic curve, saying earlier on in March before lockdown measures were in place, there was a higher level of unknown exposure, indicating more community transmission.
Now, most cases have an identifiable source. There do continue to be international travel cases, which are identified in quarantine, from reparation flights and temporary foreign workers. Twenty-seven cases have been identified in quarantine linked to international travel.
The epidemic curve from Jan. 15, 2020 to June 21, 2020. (B.C. government)
The likely source of infections from COVID-19 from Jan. 15 to June 21. (BC Government)
On Vancouver Island, the northern part of the Island has had the most COVID-19 cases since Jan 1, but only south Vancouver Island has recorded a case in the last 14 days.
Geographic distribution of COVID-19 by health service area in B.C. (BC Government)
Meanwhile, B.C.’s COVID-19 curve continues to be well below countries like the U.S. and Brazil, along with the provinces of Ontario and Quebec.
A COVID-19 case rate comparison for British Columbia. (BC Government)
A COVID-19 death rate comparison for B.C.
You can watch B.C.’s modelling presentation on CHEK’s Facebook page and YouTube channels.
B.C. has been looking at shifting from Phase 2 of its COVID-19 Restart Plan and into Phase 3, which would see the reopening of hotels, resorts, and movie theatres, among others.
According to Dr. Henry, more information on the next phase will be coming from BC Premier John Horgan later this week.
Phase 3 would allow for more travel within the province, though Henry urged B.C. residents to proceed with caution.
“If you’re considering travelling to other parts of the province, we need to be respectful. Take the same precautions that we take at home,” she said, adding that people should bring groceries with them if heading to a more remote community.
With files from The Canadian Press and CBC
Graham Cox
CHEK News
