Over half of all COVID infections in the US are now BA.5.

3 reasons why this isn't as alarming as it might seem:
- Rise in BA.5 has been gradual.
- Our immune systems are better prepared.
- Places hit first by the current wave have stabilized.

Some reasons for COVID optimism: Gradual rise:

Whereas Omicron fully established itself in 1 month, BA.5 has taken 2 months to get to 50%.

And the size of the wave has been much smaller.

Meaning that any advantage BA.5 has over other subvariants is very small, compared to the advantage Omicron had over Delta.

New COVID guidance from CDC is out:

https://twitter.com/CDCgov/status/1497317727047925760

Now setting three "community levels". Previously based on cases + test positivity, now cases + new COVID admissions + % of hosp beds occupied by COVID.

A quick hot-take🧵on pros and cons of this approach. Pro: It uses science.

This was based on measures that most accurately predicted deaths & ICU use in 3 weeks. Far better than arbitrary goals.

What will COVID look like in 2022?

Nobody knows for sure, but here's my take on the 3 most likely scenarios.

Each with reasons why that scenario might (and might not) happen.

Take home: Depends on how long & strong immunity is, w/ most people now vax'd/infected multiple times. Scenario A: 2022 is great.

COVID levels stay very low, at least until winter. Then we boost w/ COVID + flu vax.

Why so?
- Most people now have multiple doses of immunity (vax or infection).
- Many cases could be asymptomatic.
- Europe saw this in 2020 w much less immunity.

Some students have asked me: "If I want to engage w the press in my future job, what should I learn to do?"

Here's my top 10 list of responses to this question.

Bottom line: it's not about how smart you are.

Would welcome comments on this list from my journalist colleagues! 1. Treat journalists as allies, not adversaries.

Some scientists think journalists are looking for missteps that can be misquoted.

In my experience, this is not true. Journalists want to get the story right as much as we do.

Practice interviewing as friendly conversation.

Now that we've been living with Omicron for 2 months, we can use this wave to learn some lessons about
COVID in general.

First: This virus likely depends on a core group of people/settings for its spread.

We can surmise this by looking at the decline of Delta. If 1 in 3 Omicron cases is reported, the # of cases in the US now is similar to # vax'd per day in April.

Yet Delta is falling much faster today (in winter) than cases were in April.

Why? Likely Omicron (unlike vax) is infecting the people who otherwise would transmit Delta.

Though guilty myself, I wish we would stop naming waves according to variant ("delta wave", "omicron wave", etc).

This makes it seem like each wave is randomly triggered by a new variant - and there's nothing we can do about it.

But in reality, we are making a lot of progress. Each wave can be explained by a combination of behavior change, winter effect, and immunity. Without invoking variants.

And though waning immunity has played a role so far, our overall immunity is building w time. (Why the average case now is milder than early in the pandemic.)

And a quick tweetorial on how networks can make Omicron look more transmissible.

Assume:
- 2 networks, exactly the same except for # of contacts per person
- 2 variants that are equally transmissible ("50% chance of infection per contact")
- "Omicron" starts in the dense network Over time, "Omicron" spreads faster, making it look more transmissible - but only bc it's spreading in a network w/ more contacts.

Here, "Omicron" has a doubling time of one generation, "Delta" remains stable.

Even though the "variants" are equally transmissible biologically.

How can Omicron cases fall so rapidly in Gauteng if the variant is more transmissible?

Consider the analogy of a viral tweet.

Rapid early spread of any tweet is almost invariably because the "right" people RT, not because it is "good".

Same with a new viral variant. Think of young adult travelers & their contacts as "influencers" - if they pick up Omicron, many other people will be exposed.

But whether or not a viral tweet (variant) is truly "good" (transmissible) can only be determined once it gets to the rest of the population.

What's the Omicron situation, heading into the weekend?

I'm going to try to provide a balanced perspective - tough when data are so early.

I would summarize as:
"Omicron is taking over in many places - but this winter still looks much better than last." First, the bad news. Denmark. After slowing down for a bit, the virus is back to doubling every few days.

This is what one might expect in the context of an evolving outbreak, with a virus whose incubation period is 4-5 days.

covid19.ssi.dk/virusvarianter…

Denmark is doing the best variant surveillance in the world:
covid19.ssi.dk/virusvarianter…

You're going to hear from 100s of people every time Omicron cases rise in Denmark.

Which is why you need to hear from at least one person today...when they didn't.

Brief 🧵 on the data: First, Omicron is no longer doubling every few days.

The most recent data suggest that Omicron is leveling off - at the same time that Delta is reaching a peak.

(Note: I'm cutting off data from Dec 10 onward because these are not complete.)

With talk of an "inevitable omicron wave", I'm going out on a limb.

There are many determinants of COVID-19 spread:
- population immunity
- contact networks
- behavior patterns
- seasonality
- variants

Is it possible that variants are less important than other factors? (Yes.) Let's look at delta, the variant with the strongest evidence of increased transmissibility.

If the prevailing variant were the most important determinant of spread, we should see strong correlation b/w rise of delta & increase in cases.

Which we saw in the US and the UK.

Hoping to stay off twitter this weekend, but feel like the public deserves an omicron counterpoint.

Start by asking:
"What would we expect if omicron had no advantage over delta, but just happened to infect someone who started an outbreak?"

We must account for random chance. You may think this is really unlikely - but maybe not.

SARS-CoV-2 is very prone to superspreading.

It's not like every person who's infected transmits to 1 other person.

Rather, ~1 in every 40 people who are infected will transmit to >20 other people.
bit.ly/3xTsCjY

#Omicron is already a massive #scicomm failure.

Easy to say "we're just reporting data," blame leaders for acting like normal humans.

As Joe would say, "c'mon, man." Who didn't think this would happen?

It's scientists' job to present early data w caution. And we have failed. 1. We're talking about <200 confirmed cases so far, over 2 weeks. Out of >600k per day worldwide. bit.ly/312HH6H

Meaning omicron likely accounts for <0.01% of all COVID cases worldwide.

Not to say this won't increase - but we need to maintain perspective.

I'm 3 days late, but this piece in @JAMAInternalMed is worth a mention: bit.ly/31TVBID

Average people in France.
Asked if they thought they got COVID in the past ~6 months.
Tested to see if they were right.
Then asked if they had "long COVID" sx's.

Quick 🧵... Focusing on % of people reporting "brain fog" (poor attention/concentration) for >8 wks.

Had COVID & realized it: 8.5%
Had COVID & didn't realize it: 2.7%
Didn't have COVID but thought they did: 7.5%
Didn't have COVID (& didn't think they did): 2.2%

Other results are similar.

Head spinning from all the COVID mix-and-match possibilities from tonight?

Below is what I would do, in different scenarios. Trying to stay simple. With rationale & data.

This is not official guidance, just personal opinion. Assuming CDC will follow FDA authorization. Scenario 1: You haven't been vaccinated, but have been infected.

Recommendation: Get a vaccine. Preferably an mRNA vaccine (Pfizer or Moderna).

Rationale: Even if you've been infected, getting a vaccine offers protection against reinfection.

Data: bit.ly/3aXiw7a

I am optimistic that we will not see another big wave of COVID hospitalization & death in the USA.

Why?

Don't call it "herd immunity." But the vast majority of adults in the US have either been vaccinated or infected by now.

Thread on the US pandemic present & future... First: What fraction of US adults have been vax'd or infected?

Estimated 1/3 infected by Dec 2020: go.nature.com/3vawFHb

20% of blood donors infected (+ 63% vax'd) by May 2021: bit.ly/3mPkr37.

So pre-delta, likely at least 1/3 of unvax'd adults had been infected.

Six months ago, 15% of Americans had been fully vax'd.

How is vaccine effectiveness (VE) holding up? I looked up VE estimates over time, state by state.

Long story short: VE has been remarkably stable over the last 2 months.

If immunity is waning, it's not waning fast. California: VE 84% on July 31, 87% now.
bit.ly/39IiOy0

A 🧵 for non-scientists on vax & boosters, using data from @KCPubHealth.

Seattle shows us "case relative risk", comparing unvax'd vs vax'd, over time (bit.ly/3ESvUqV).

Think of this as "level of vax protection".

Since late July, it's been stable, even going up. Think of this number as "how many times more protected you are vs COVID if vax'd vs unvax'd."

There are 2 factors likely to affect this.
1. How long since your last shot (waning)
2. Level of exposure in the community (when exposure is intense, vax may not prevent all infections)

I applaud the ACIP for taking a nuanced stance.

But am hearing lots of concern from vax'd under-65s who are worried their immunity will be gone 6 months after their 2nd shot.

To address this, let's take a tour of 2 populations of about the same size: Israel and Virginia. First, Israel. It's essential to debunk this myth:
"Israel vax'd its population first.
It now has high COVID rates.
Vax immunity must be waning."

This storyline has a lot of problems.

First, 50% vax coverage was only achieved 6 months ago (Mar 17), 4 mos before the surge.

The big COVID news, dropped on a Fri afternoon:
"effectiveness vs COVID-19 hospitalization was higher for Moderna than Pfizer (and Janssen/J&J)."

bit.ly/3kjuoFR

But let's take a look at the analysis before accepting these results at face value... 1. Here are the data - on the surface, looks like Moderna effectiveness is constant at 92-93% after 120 days, Pfizer drops from 91% to 77%.

(btw, this was CDC not Pfizer funded, but what a great strategy for Pfizer - push "waning immunity" so people need a 3rd dose of your vax)

A visual representation of what we know and don't know about waning immunity.

We know, at 6-8 months:
- Partial vax not great.
- Full vax ~70-85% effective (better vs severe disease than infection).
- Booster gives short-term bump.

We don't know what happens next.
4 scenarios: Scenario A: Booster gives long-term benefit (by increasing immune memory), and immunity to 2-dose series continues to wane.

In this scenario, boosters are the right thing to do, now.