Thoughts on @CDCgov mask update

They got the science right: fully vaccinated folks don't need to wear masks indoors

Of course, there is one major problem: how do you know who is vaccinated?

States/companies are getting policy response to CDC guidance wrong

thread
In response to CDC, states/businesses have 3 choices:

1. Figure out who is vaccinated or not (hard to do but not undoable)

2. Drop mask requirements for everyone, hope for honor system (easy to do, not great)

3. Keep masking a bit longer (not hard to do, much better)

2/n
Option 1: figure out who is vaccinated

I get this is hard. Vax verification systems are coming but not here yet

Option 2: Drop mask mandates and hope

Not a good idea. Why? Lots of folks still not yet vaccinated. Infection levels high

Option 3: wait about 4 more weeks

3/5
So here's why business/states should wait a bit

1. People who became eligible on 4/19 (rule followers who didn't jump line) will become fully vaccinated no later than 6/15

2. Infection levels still high across country but falling

In about a month, we'll be <20K cases/day

4/5
Bottom line

People angry at CDC not for what they said but how others use what they said

I get it

But lets focus on getting states, businesses to implement policy right

Either do hard work of figuring out who is vaccinated (vaccine passports)

Or wait 4 weeks

End

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More from @ashishkjha

16 May
A lot of folks wondering since I'm fully vaccinated, why would I wear a mask at a grocery store?

Every action we take is a weighing of costs and benefits

So lets talk about fully-vaccinated me in a grocery store

Am I a risk to others? No

Am I at risk? Not much

Thread
So whats the risk to me?

Right now, infection numbers still high in MA, although falling

And if grocery store has lots of unvaxed, unmasked folks, I have a tiny risk of picking it up

Tiny

But cost of masking up is also tiny

But that's not the real reason

2/4
There are lots of folks who want to be but are not yet fully vaccinated

My wife for instance

She got her first shot right after she became eligible

She's close but not fully vaccinated. There are lots of folks like her

And by masking up, I help create a norm in society

3/4
Read 5 tweets
9 May
Wrote about why India likely has 25K+ deaths daily

Pushback: we lack hard data on crematoriums so we can't be sure

True

But we get 25K+ deaths no matter how you look

Another approach:

400,000 cases, 22% test positivity

Likely means we're missing 90% of infections

Thread
Here's a way to think about it:

In the US, 60K cases from 3 weeks ago leading to 600 deaths today

A case fatality rate of 1%

But my best guess of infection fatality rate (IFR) in US now is 0.5%

So that means US missing half of infections

With a test positivity of 4%

2/5
So in the US, for every 25 test we perform, there is 1 positive

But we're still missing half the infections

In India, every 4 tests turns up 1 case

Meaning India missing a vast, vast majority of infections

Probably around 90%

So true # of infections in India closer to 4M
Read 5 tweets
9 May
India reports another 400,000+ cases, 4000+ death day

A sustained level of horribleness

And its not correct

True number surely closer to 25,000 deaths, 2-5 million infections today

Lots of ways to estimate but here's a simple one

Look at the crematoriums

Thread
During non-pandemic year 2019

About 27,000 Indians died on typical day

Crematoriums handle that level of deaths every day

Additional 4,000 deaths won't knock them off their feet

Crematoriums across the country reporting 2-4X normal business

2/4
So best estimate 55K to 80K people dying daily in India

If you assume baseline deaths of 25-30K

COVID likely causing additional 25K to 50K deaths daily

Not 4,000

What about infections?

Lets start with Infection Fatality Ratio (IFR)

In India, at least 1% right now

3/5
Read 6 tweets
7 May
Will we reach herd immunity?

We might. In some places. For periods of time

And not sure it matters that much

Experience from UK, Israel clear

Get enough folks vaccinated, pandemic fades into the background

My latest in @PostOpinions

washingtonpost.com/outlook/2021/0…
Few points from the piece:

1. herd immunity threshold varies based on variant of SARS-CoV2, vaccination rates, prior infection rates, who has immunity, so forth

2. Herd immunity not a one and done. We've had HI for measles. Then vaccinations fade -- and it pops back up

2/3
3. Herd immunity does not eradicate the virus

4. Some places in the US have high degree of immunity and likely will hit herd immunity with more vaccinations. Others won't

So here's the bottom line:

This pandemic will end here in the US even if the virus isn't gone

3/4
Read 4 tweets
3 May
Folks being critical or misunderstanding this very good @apoorva_nyc piece

5 points that this piece pulls together nicely

1. Last year, we all assumed herd immunity threshold (HIT) would be 60-70%. Now clear its higher

This is not tragic

Thread

nytimes.com/2021/05/03/hea…
2. HIT may be 80%. Seems high

But its possible we might get there. We're about 60% population immunity now

As we improve access, make vaccinations easier, open up to kids, will get into the 70s

3. HIT not an on/off switch. Its not like we hit 80% and disease disappears

2/4
Already, we are seeing high levels of population immunity have large effect on dampening cases

My thread from yesterday:



States like RI, MA, SD already at 70% population immunity. They might get to 80% before long

covid19dashboardgt.shinyapps.io/us_immunitylev…

3/5
Read 5 tweets
2 May
At what point should we see cases in US begin to drop sharply from vaccinations?

Complicated but experience from Israel says 45-50% of population vaccinated

US is shy of that

But some states past that threshold

So do we have evidence its working there?

Why yes we do

Thread
Lets look at top 5 vaccinated states

NH, MA, CT, VT, ME

All >50% of population 1+ dose

So what's happening with cases (c/w 2 wks ago)?

NH down 44%
MA down 37%
CT down 40%
VT down 46%
ME down 42%

I know, all New England states

Lets look broadly at cases & vaccinations

2/4
If we take the 10 states with largest drop in cases

Average vaccination rate 49.8%

The 10 states where cases actually rising?

Avg vaccination rate 39.9%

It appears somewhere around 45-50% population vaccinated (65% or so adults vaccinated)

cases really turn down

3/4
Read 4 tweets

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