Thread by @ashishkjha

CDC revised its mask recommendations for vaccinated people

Its causing relief among in some circles, confusion in others and anger in others yet

My take?

A modest change with likely modest effects

A change that is responding to the realities on the ground

Thread

So here's the thing

Changing guidance in response to new evidence isn't flip-flopping

Its what we should always do

CDC said in May that vaccinated people are largely safe (they rarely get infected, they don't spread)

That was correct

At the time

Before Delta showed up

2/5

With delta:

unvaccinated people have 1000X the viral load of the previous variant

And now, new data (we haven't seen it yet) suggests:

While breakthrough infections are uncommon

But when they happen, some vaccinated folks have a high viral load too

Not ideal

3/6

So you're CDC

You see:

Infections up 4X nationally in past month

up 7X in Florida, Louisiana
8X in Arkansas

And you know:

1. When there is that much virus circulating, vaccinated folks will have breakthroughs

2. Some of those breakthroughs will cause forward transmission

So they recommended that vaccinated folks mask up in high transmission communities

This is a recommendation

Its reasonable

And here's the thing, it'll help. A little

Why a little?

Many folks wear poor quality masks that help only a little against delta

And because.....

5/7

A lot of transmission happens in places with little masking

Think bars, restaurants, parties, etc

And...

Vaccinated folks who'll comply with guidance were already masking

Not sure this guidance moves unvaccinated, unmasked folks

Who are the real drivers of this surge

6/7

So is this policy change based on data?

Yes

Will it make help a lot?

Not really

So what will make a big difference?

1. Reduce indoor gatherings, dining, bars, etc

Yeah, that's neither tenable nor sustainable

2. Vaccinating lots more folks

So that's what we have to do

Fin