June 29, 2020 - Dr. Archer's Update on COVID-19 response from the DOM and Medicine Program
Important update (new outpatient cases)
Local COVID-19 Update KFL&A:
The running total for the epidemic is now 79 cases in the KFL&A region (see update from KFL&A Public Health). There are no COVID-19 cases in hospital. However, there are 27 cases reported in the last week (I believe KFL&A website will be updated to reflect this this afternoon). All cases are recovering from COVID-19 in the community.
All the new cases relate to the outbreak in 2 local nail salons (1 from Kingdom Nails & Spa and all the rest from Binh’s nail salon). To date all cases have been people who have been employees of or have had direct contact with one of these sites. Thus, we are advocating testing and 14 days quarantine of “first circle contacts” (i.e. people who were actually clients of the nail salon). The risk of infection in secondary contacts (i.e. people in contact with people who attended the nail salon but who did not attend the salon themselves) is an order of magnitude lower and there is no need for testing or quarantine if they are asymptomatic.
These new case put us close to the Public Health threshold of > 10 cases/100,000 in the region. At this threshold hospital ramp-up is stopped to preserve COVID-19 capacity (which would be very bad for the 99.9% of people who do not have COVID-19 disease).
Currently there are 45 KHSC staff on quarantine but to date there are no new positive cases beyond the one reported ~10 days ago.
Testing is now being performed at the Leon's Centre (click here for details). We have done ~1988 tests over the weekend, with 7 positive tests, 3 from KFL&A and 4 from the Haliburton-Kawartha area. Congrats to Cindy Bolton, Ashley Hendry and team who arranged a pop up testing clinic in the St. Lawrence College parking lot as a bridge to opening the Leon Centre (now open). There will be another pop up clinic at St. Lawrence College on July 1st.
KHSC quarantine: Davies 5 remains in quarantine even though all tests of patient and staff to date are negative. More testing will be done on Monday to determine when quarantine can be lifted.
Does asymptomatic infection cause immunity? An interesting study in Nature (click here) examined the immune responses of people with asymptomatic COVID-19 infections. This study from Wanzhou China examined 2088 close contact of individuals who were quarantined and assessed their rate of SARS-CoV-2 infection. They identified 37 asymptomatic cases, defined as individuals with a positive PCR result but without any relevant clinical symptoms in the preceding 14 days. They identified a total of 178 patients with confirmed SARS-CoV-2 infections in this cohort of people. Thus asymptomatic people accounted for 20.8% (37/178) of all positive tests. They then compared the antibody detection and cytokine measurements in the 37 asymptomatic people with matched patients who were mildly symptomatic. Interestingly although asymptomatic, half these patients had mild CT scan abnormalities, mostly focal ground glass opacities. The asymptomatic people had similar viral load on RT-PCR testing, with detection of the ORF1ab and N gees at ~33 cycles of PCR, just like the symptomatic people). However, asymptomatic people shed virus longer (19 vs 14 days) (see below). This doesn’t mean they were infectious at 19 days since detection of viral RNA doesn’t always mean that infectious virus is present in respiratory specimens.
Symptomatic and asymptomatic people had similar immune response in the early phase of infection, although symptomatic people had higher IgG immunoglobulin (antibody) levels (see graph below).
However, in the recovery (convalescent) phase, the % of patients with detectable antibody levels was lower in asymptomatic people (60%) than in symptomatic patients (87.1%).
Consistent with the lack of symptoms, the asymptomatic people had lower levels of inflammatory mediators called cytokines. The authors’ main point is that asymptomatic people had less robust immune response and this might mean that their mild infection will leave them vulnerable to reinfection (which would compromise the notion of society building herd immunity). It’s too early to conclude this but it is noteworthy that with SARS, an earlier coronavirus infection, antibody positivity persisted for > 34 months. Even for SARS-COV-2 tests in symptomatic people most show they have detectable levels of neutralizing antibodies.
Take home message: It is too early to know for sure whether people with asymptomatic COVID-19 infections develop long-term immunity; however this study raises concerns that they might be prone to reinfection.
A reminder to researchers entering KHSC: If you are performing research at KHSC you should have an approved protocol, approval to proceed with your research from Dr. Steve Smith VP research AND your research unit should provide you with the necessary PPE to enter the facility. The hospital is reserving PPE for clinical use and authorized patient visitors. So, please ensure bring that you bring your mask when you pass through screening. Queen’s is looking into obtaining more PPE for research staff, stay tuned.
Symptomatic KHSC staff: Should KHSC staff develop symptoms consistent with COVID-19, please contact occupational health and safety and they will tell you how to proceed (ext 4389 at KGH site, or email COVIDrtwadjudication@kingstonhsc.ca). You will likely be tested at the Hotel Dieu testing centre. Do not come to work!
Kingston’s bubble may not have burst; but it is fragile (37.6 cases/100,000 population). Toronto has a rate ~11 times higher (417.5 cases/100,000 population). The prevalence in Toronto has increased every day for the past month, reflecting neighbourhood hot spots. Provincially the epidemic is in modest decline. There were 178 new cases yesterday and 34,654 total cases and 2658 deaths to date. The 1.0% rate of positive SARS-CoV-2 tests on June 28th was down -0.4% compared with June 27th.
The prevalence of cases in Toronto is still increasing daily due to over a dozen neighbourhoods which are COVID-19 hotspots, defined as rates over 1000 case/100,000 (click here), including: Moss Park, Newton Brook West, Yorkdale Glen-Park, Downsview Roding CFB, Maple Leaf, Rexdale-Kipling, Black Creek, Mount Olive, Beechborough, York University Heights, Mount Dennis, Glenfield Jane Heights, and Weston. Humber Heights Westmount, a neighbourhood in Etobicoke , with 1699 cases/100,000, has the highest prevalence in Toronto. The ministry has deployed public health experts, mobile testing facilities and contact tracers to deal with these “epidemics within epidemics”.
How’s Canada’s epidemic going? We have had 103,246 cases of COVID-19 in Canada and 8522 deaths (see below). There is a slight female preponderance in cases (but mortality is higher in males). The number of active cases per day is declining slowly (orange bar and line graphs below right). Quebec remains the hot spot, accounting for 53% of all cases in Canada to date.
Canadian aggregate data
The epicentre for COVID-19 mortality remains our long term care facilities (LTC) (see today’s data below). The ~78,000 residents of Ontario’s LTC facilities account for less than 0.5% of the population but they account for 68% of all deaths from COVID-19! There were 2 deaths since yesterday in Ontario LTC centres. Canada had the highest rates of mortality in LTCs of any survey country. 81% of all COVID-19 deaths occurred in residents of LTCs (click here)! This is sad, embarrassing and requires rapid change in how we license, fund and monitor LTCs.
Testing for SARS-CoV-2 (click here): We have tested 7.51% of all Canadians (2,898,702 people). Nationally, 3.56% of all tests are positive (vs 2.55% in Ontario). Ontario SARS-CoV-2 testing is exceeding the national average for testing, with a rate of 9.37%.
The COVID-19 pandemic has exceeded 10 million cases. The pandemic hot spots are in the Americas (Brazil and USA), Russia, UK and India (click here). The global case total is 10,168,657 and the number of death is 502,387 (click here): The graph below shows (the world’s hot spots (more red=more COVID-19).
America: I have children and many friends and colleagues in the United States and so I report the data below with a heavy heart (click here). The failure of leadership in America regarding implementation of a national public health response to the pandemic has been spectacular and the COVID-19 incidence is rising in proportion to this. These are concerning times for our friends, family and colleagues in America. We can only wish them well and hope that rational public health policies are enacted to try and limit the damage. Certainly we will not be seeing the border opening in the near future.