Skilled Nursing Facility Asymptomatic Achilles Heel

I had a brief look at the study you just linked. Some observations I would make:

1. It looks at an older population at a skilled nursing facility. How can we rule out co-morbidities and weaker immune system/vitamin D levels?

2. When I look at their statement and their references for:
“A key factor in the transmissibility of Covid-19 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 Viral loads with SARS-CoV-1, which are associated with symptom onset, peak a median of 5 days later than viral loads with SARS-CoV-2, which makes symptom-based detection of infection more effective in the case of SARS CoV-1.3” – I just don’t see any hard scientific studies proving what they just said.

Reference 1 is preprint, so not good science yet.
Reference 2 is back in 2004 for SARS1.
Reference 3 is an observational cohort study in 2 hospitals of a small sample size of 30 patients.
Reference 5 was again in a skilled nursing facility (related to the same one as study 1?) and what I interpret as having a non-conclusion ending (“most likely contributed to…”). “Most likely” is not very conclusive:

“Rapid and widespread transmission of SARS-CoV-2 was demonstrated in this skilled nursing facility. More than half of residents with positive test results were asymptomatic at the time of testing and most likely contributed to transmission. Infection-control strategies focused solely on symptomatic residents were not sufficient to prevent transmission after SARS-CoV-2 introduction into this facility.”

And given WHO’s June 8 initial press release that there’s no asymptomatic transmission, then I might even say that Reference 5 (“most likely contributed to transmission”) would fall in line to what WHO just retracted but contrary to BC Chief Medical Health Officer and the asymptomatic study with 455 folks.

I haven’t had time to thoroughly critique the study you just linked, but my sense is that if it has any applicability, it is only for older populations in skilled nursing facilities.