Daily briefing
There were no press briefings on Saturday, Sunday or Monday but the government sent out press releases all three days:
On Saturday, the province announced six additional COVID-19 deaths, five at the Northwood long-term-care facility (LTCF) in Halifax and one in the Western Zone, involving a man in his ’80s with underlying medical conditions who was not a LTC resident. Fifteen new COVID-19 cases were confirmed.
Dr. Robert Strang during the COVID-19 Update for 24 April 2020.
On Sunday, the province announced two additional deaths at Northwood, the Halifax LTC home, and eight new cases of COVID-19.
Today, the province announced 27 new cases of COVID-19 and no new deaths. Of note: the majority of the new cases were not at Northwood or any other LTCF. In fact, compared to Sunday’s totals, there was only one new case associated with a LTCF.
Numbers
Total new cases: 27
Total cases: 900
Total hospitalized: 12
Total in ICU: 3
Total recovered: 509
Total deaths: 24
Total long-term-care facilities (LTCF) affected: 10
LTCF residents: 198
LTCF staff: 95
Total positive and negative tests to date: 27,131
Age range of patients: under 10 to over 90
Long-term-care
Ontario has begun publishing the names of long-term-care facilities with active COVID-19 outbreaks, explaining that active means:
…the home has at least one lab confirmed case of COVID-19 (in resident or staff) and the local public health unit or the home has declared an outbreak.
It is also (further down the same page) publishing the names of LTC homes where outbreaks have been resolved.
Quebec also publishes LTCF outbreak statistics.
Lucky New Brunswick
The CBC’s Jacques Poitras looked at the factors that have (knock wood) protected New Brunswick from a worst-case COVID-19 scenario.
Interestingly, many of them (like the lack of an international airport) were previously viewed as negatives.
Asymptomatic spread
The topic of the day in COVID-19 coverage is “asymptomatic spread” of the virus and I found this April 24 editorial — “Asymptomatic Transmission, the Achilles’ Heel of Current Strategies to Control Covid-19” — in the New England Journal of Medicine (NEJM) very informative.
The authors — Monica Gandhi, Deborah S. Yokoe and Diane V. Havlir — begin by explaining that:
Traditional infection-control and public health strategies rely heavily on early detection of disease to contain spread. When Covid-19 burst onto the global scene, public health officials initially deployed interventions that were used to control severe acute respiratory syndrome (SARS) in 2003, including symptom-based case detection and subsequent testing to guide isolation and quarantine. This initial approach was justified by the many similarities between SARS-CoV-1 and SARS-CoV-2, including high genetic relatedness, transmission primarily through respiratory droplets, and the frequency of lower respiratory symptoms (fever, cough, and shortness of breath) with both infections developing a median of 5 days after exposure.
Unfortunately, that’s where the similarities between the two coronaviruses ended:
Within 8 months, SARS was controlled after SARS-CoV-1 had infected approximately 8100 persons in limited geographic areas. Within 5 months, SARS-CoV-2 has infected more than 2.6 million people and continues to spread rapidly around the world.
SARS-CoV-1 is more deadly than SARS-CoV-2 but harder to transmit from person to person. A key factor in the differences in transmission and spread between SARS-CoV-1 and SARS-CoV-2, the authors say, is:
…the high level of SARS-CoV-2 shedding in the upper respiratory tract,1 even among presymptomatic patients, which distinguishes it from SARS-CoV-1, where replication occurs mainly in the lower respiratory tract.2
At this point, I had to go and look up the precise difference between the upper and lower respiratory tracts, so with apologies to those of you who already know this, the upper respiratory tract consists of the nose, sinus pharynx and larynx and is mainly involved in the conduction and cleaning of air. The lower respiratory tract includes the trachea, bronchioles and alveoli and is primarily responsible for gas exchange. Here’s a diagram I’ve borrowed from Wikipedia:
When the virus enters your system, it attaches itself to a cell and uses that cell’s own machinery to replicate itself — one cell can produce thousands of new viruses that are released from the infected cell and can go on to infect other cells or end up in droplets that go on to infect other people. The process by which infected cells release new copies of the virus is called “viral shedding.”
Basically, with SARS-CoV-2, it seems there is more shedding of “live virus” from the nasal cavity in the upper respiratory tract and it can happen before an infected person exhibits symptoms. I think it’s worth comparing this to influenza, because the response to COVID-19 in long-term-care facilities, for example, is based on public health’s influenza protocols. According to Gandhi, Yokoe and Havlir:
With influenza, persons with asymptomatic disease generally have lower quantitative viral loads in secretions from the upper respiratory tract than from the lower respiratory tract and a shorter duration of viral shedding than persons with symptoms,4 which decreases the risk of transmission from paucisymptomatic persons (i.e., those with few symptoms).
The editorial concerns itself specifically with what this means for controlling the virus in nursing homes and it focuses on a study, published that same day in the NEJM, called, “Presymptomatic SARS-CoV-2 Infections and Transmission in a Skilled Nursing Facility
The study was conducted in a healthcare facility in Washington State where a symptomatic healthcare worker tested positive for the virus prompting testing of all residents and staff. Arons et al, the authors of the study, divided the 76 (of a total of 89) residents who agreed to be tested into four categories: residents with typical symptoms (fever, cough, shortness of breath), those with atypical symptoms, those who were presymptomatic, and those who remained asymptomatic
The authors found that fully half the residents who tested positive exhibited no symptoms at the time of testing. They also discovered that samples collected from patients in all four categories, including asymptomatic and presymptomatic, had “similarly high” viral loads. This led them to conclude that:
Current interventions for preventing SARS-CoV-2 transmission in health care settings rely primarily on the presence of signs and symptoms to identify and isolate residents and staff who might have Covid-19. The data presented here suggest that sole reliance on symptom-based strategies may not be effective to prevent introduction of SARS-CoV-2 and further transmission in skilled nursing facilities. Impaired immune responses associated with aging and the high prevalence of underlying conditions, such as cognitive impairment and chronic cough, make it difficult to recognize early signs and symptoms of respiratory viral infections in this population.16 Studies have shown that in the elderly, including those living in skilled nursing facilities, influenza often manifests with few or atypical symptoms, delaying diagnosis and contributing to transmission.17,18 Furthermore, symptom-based cohorting strategies could inadvertently increase the risk of SARS-CoV-2 exposure for uninfected residents, given that typical symptoms were common in those who tested negative.
The measures laid out in Nova Scotia’s infection prevention and control guidance for LTCFs, most recently revised on April 24, are largely reliant on screening residents and staff for symptoms, but the document does state:
Note: Symptoms in elderly residents may be subtle or atypical, and screening staff should be sensitive to detection of changes from resident baseline. The goal of active screening is to have a low threshold for detection of COVID-19 cases. Testing may be appropriate in some circumstances based on clinical knowledge and judgment, taking into consideration the resident’s baseline health status.
I should also add that testing is stepped up in a facility once a case is found, but I’m not sure what protocols guide this, the relevant document states:
Upon one positive COVID-19 result, determination of additional testing will be in consultation with local Public Health.
The NEJM editorial argues that the rapid spread of the disease, the clear evidence of asymptomatic spread and “the eventual need to relax current social distancing practices” all “argue for broadened SARS-CoV-2 testing to include asymptomatic persons in prioritized setting.”
Moreover, they say the same factors also “support the case for the general public to use face masks10 when in crowded outdoor or indoor spaces.”
Nova Scotia’s response has been evolving as the science of COVID-19 has evolved and we’ve broadened testing considerably from the early days of the epidemic when we concentrated quite intensely on travelers, but we are still very much focused on testing people who exhibit symptoms. It will be interesting to see how findings about asymptomatic spread will shape Nova Scotia’s response as we start to talk about lifting some restrictions.
Tonight’s Distraction
SubCulture presents a special live stream premiere of Tony Award-winning composer/lyricist Brown’s 58th residency concert, with special guests ARIANA GRANDE and SHOSHANA BEAN.
The concert is presented as part of a benefit for the SubCulture staff and the musicians from the Jason Robert Brown Artist-In-Residence concerts during the COVID-19 epidemic.
It begins at 9:00 PM ADT
Jason Robert Brown and Shoshana Bean // Photograph: Erika Kapin
