So #COVIDzero is trending.

What's not to like about zero cases of #COVID19?

1. How can we get there?
2. Is this feasible in Canada?

Some unpopular opinions & perhaps a few hard truths below...
2/ With a #COVIDzero strategy or not, it is clear that we should improve/continue to:

1. Evaluate & address drivers of #COVID19 in the community

2. Bolster a Test-Trace-Isolate-Support system

3. Support communities & businesses disproportionately impacted by the virus

3/ What would it actually take to *operationalize* #COVIDzero in Canada? How do we get to (or near) zero cases & maintain it?

***It would take prolonged & full lockdown (3-5 months based on current burden?) where #COVID19 is crushed, then ongoing supports to suppress this***

Some notable successes include Taiwan, New Zealand, Australia, Atlantic Canada, and a few others...

And they are reaping the rewards.
5/ But several of aspects to achieve #COVIDzero must ALIGN to be successful (e.g. like that Swiss cheese model), including:

1. Federal government support
2. Federal public health support
3. Provincial government support (all)
4. Provincial public health support (all)...
5. Municipal government support (all)
6. Regional public health support (all)
7. Community buy-in for prolonged pan-Canadian lockdown
8. Enforcement of lockdown measures
9. Massive support for communities impacted by lockdown
10. Support+++ for businesses impacted by lockdown

11. Halting interprovincial travel

12. Halting regional travel (eg 5 km radius from home in Victoria, Australia)

13. Bolster diagnostic testing capacity country wide

14. Bolster contact tracing capacity country wide

15. Stay at home orders (no private social gatherings)

16. Ensuring everyone who cannot isolate has a safe place to do so, even if they don't want to isolate...

17. Creating a reliable pan-Canadian surveillance program (e.g. waste water, syndromic surveillance, etc)

18. Ensuring supply chain intact for medical & essential goods

19. Strict border control/screening for incoming people & goods (see link below & the tremendous volume of travel over Canada/US border for *essential* goods)

20. Ensuring safe workplaces (e.g. factories, etc), systems in place for paid sick leave.


I am sure that I am missing some major ones above - please add/correct any. This is just a first pass.
Think of what it takes to achieve #ZEROcovid. Realistically, how successful have we been with many of these like testing, contact tracing, surveillance, supporting marginalized, esp. in hot spots? 🦗🦗🦗
Now ask yourself is #COVIDzero probable, aspirational, feasible?

I think we have to be honest with ourselves & the public about what it would take to get there, what our capacity/appetite is, & the likelihood of this being successful.

And of course, it would be great to have zero (or near 0) #COVID19, but will we?

Also consider timing - getting to or near zero covid will take ~4+ months, around the time vaccine roll-out is likely to start (which will take time to do country-wide) & will prioritize the most vulnerable populations first e.g. those in LTC, who account for >80% of deaths.


1. CAN #COVIDzero work? Theoretically possible.

2. WILL this work? Canadians will have to decide, not just those on Med/Epi/COVID twitter.

3. Regardless of #1 & #2, SHOULD we drive cases lower, boost Test-Trace-Isolate capacity, support vulnerable? Of course.

Let's talk #COVIDzero when a vaccine rolls out.

Or aim for something realistic, like zero #COVID19 deaths....


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More from @BogochIsaac

16 Nov
Wow - More positive #COVID19 vaccine news.

Moderna's interim analysis shows ~95% efficacy in their Phase 3 trial!

Yes, lots of unanswered questions & more science by press release, but very positive news none the less.

Other very helpful points:

"Of 11 participants who developed severe Covid while on the trial, all were in the placebo group."

"The results also suggest the vaccine is effective in older people and those from diverse ethnic backgrounds."

From a logistical standpoint - MUCH easier to transport.

"the vaccine can be kept in a conventional freezer at -20C for up to 6 months and that once thawed the vaccine can be kept for up to 30 days at standard refrigerator temperatures of 2 to 8C."
Read 6 tweets
13 Nov
Very reasonable adjustments to the #COVID19 response in Ontario.

-Limit trips
-Work remotely
-Stay within your household

Significant adjustments to the colour-coded framework:

*Red Zone thresholds lowered* from 10% positivity to 2.5%; 100 new cases/100k to 40/100k. Image
It took a while, it took some pushing (translation: it took a lot of pushing), but the province moved on this. Phew. Good move.
Here is the updated framework.

ontario.ca/page/covid-19-… Image
Read 5 tweets
9 Nov
"A vaccine against #COVID19 is in sight, with the announcement of the first interim results in large-scale trials showing the Pfizer/BioNTech candidate is 90% effective"

Pro: Amazing- if this holds true.
Con: Science by press release, let's see the data.

ps: Canada has access to this one.

pps: While clearly very promising and exciting, best to see the final data on safety and efficacy.

ppps: "People from black and minority ethnic backgrounds appear to have been as well protected as everyone else, the company says."
Additional helpful details:

-Trial is enrolling 43000 people
-They've had 94 cases of #COVID19
-Much more covid in non-vaccinated group...less than 10% of those vaccinated diagnosed with covid
-Protection seen 7 days after 2nd dose of vaccine
-Goal is to enroll up to 164 cases
Read 6 tweets
11 Oct
Fomite transmission (from inanimate objects) of SARS-CoV-2 is much less of an issue than previously thought.

Some recent data:

Hand hygiene is still important & I hope better hand hygiene is a lasting legacy of this pandemic.
Policy is keeping up with emerging data...

For example the CDC acknowledges that one can get infected from touching contaminated surfaces, but adds...

"Spread from touching surfaces is not thought to be the main way the virus spreads."

Also, in a recent Lancet letter:

"Our findings suggest that environmental contamination leading to SARS-CoV-2 transmission is unlikely to occur in real-life conditions, provided that standard cleaning procedures and precautions are enforced."

Read 4 tweets
19 Sep

More data demonstrating the low (but not 0%) risk of acquiring #COVID19 on flights.

2 business class passengers likely transmitted virus to 2 flight attendants on this 15 hour flight in early March, 2020.

No mention of masks.


2nd example: On a 10 hour flight, 1 person (also reported in business class) likely transmitted to 16 others, out of 217 passenger & crew. Proximity a risk.

Once again: "Face masks were neither recommended nor widely used on airplanes in early March"


Could there be something about business class that facilitates transmission (e.g. seating arrangement/air flow, lax mask use)? Is this a real issue vs reporting bias? Not sure.

Other examples of rather limited #COVID19 transmission on planes here 👇

Read 4 tweets
30 Jul

#COVID19 transmission on a train:

This study quantified the risk of infection based on duration and proximity to an infected person.

"Overall attack rate of COVID-19 in train passengers with close contact with index patients was 0.32%"


TIME on train:
-Attack rate with 1-hour co-travel time is 0.25%, and with 7 hours 0.38%

PROXIMITY to case:
-Closer to index case = higher risk (shocker).
-3.5% attack rate if sitting next to case
-Attack rate drops significantly if >2 rows apart

Take home points:

-Spread apart as much as possible
-Wear a mask
Read 4 tweets

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