Thread by @ASlavitt

COVID Update: Is there evidence of the vaccine’s immunity waning? What does new data showing lower efficacy in Israel mean? 1/

Several weeks ago reports started coming out of Israel, the first country to drive widespread vaccination, that the vaccines were showing lower efficacy against moderate symptomatic COVID. (Against severe COVID, the vaccine is still highly protective with a slight dropoff.) 2/

A more recent study made public late last week showed lower efficacy still among the same group at 39% and severe COVID at closer to 90%, also a drop, though more modest. 3/

At the time of the first study, 3 weeks ago, I put out the following thread suggesting one key explanation could be that the vaccines were showing some signs of waning immunity at least in certain populations after 6 months or so. 4/

https://twitter.com/ASlavitt/status/1412229839210254346

After conversations with Pfizer the White House & scientists, much of which will be on @inthebubblepod next week, I asked these questions.

These new numbers may or may not be indicative but one conclusion seems to be that immunity indeed could be waning at 6 months or so. 5/

While still not perfectly clear, the answers are seeming less muddled than before.

In the main, there are clear signs that antibody levels from the second shot wanes at 6 months. What isn’t clear is whether memory B and T cells offer continued protection. 6/

The longest data we have is on the original 35,000 trial participants and on the Israeli public.

While there isn’t clear agreement yet, I can’t find anyone to dispute that boosters will be recommended in our near future. 7/

But while this is determined here in the US, there are questions that aren’t yet settled.
-Who for & when?
-With what formulation?
-With what benefit & frequency?
8/

Who for & when?
-Likely: People with immune system issues & elderly
-Potentially: Some portion of people at 6 months post vaccine 9/

What are the data in Israel saying? Higher amounts of mild breakthrough cases & elevated through still very low levels of serious cases. In Israel, still no increase in deaths nationwide. 10/

Would the formulation of the boosts be more of the same or a special booster designed for the variant?

A booster of the current formulation seems to confer many multitudes the antibody response.

Variant specific boosters have been made in the lab but do not appear needed.11/

Given the very strong response in the lab, the FDA needs to consider side effects & target populations even as they look at durability before they make a recommendation. 12/

How much durability will it confer?

The hope is that for those for whom a third shot is warranted, protection would last a year or more. This couldn’t be known of course at this point. 13/

Another booster on its way isn’t at this point isn’t the news we hoped for, but neither is it too concerning.

For one, these are easy to produce, highly scalable vaccines & the US has already procured enough & set up distribution for boosters. 14/

And the time to create a new vaccine if needed to tackle a new variant is under 100 days. 15/

Further good news is that with trillions of reproductions of the virus and many many variants, including 4 major ones, nothing has outsmarted the mRNA platform & the scientists yet. 16/

And most importantly even if immunity begins to wane here in the US, there remains strong protection against severe COVID in the interim. 17/

The implication for layered protection like mask wearing is inescapable.

If indoors with people whose status you don’t know, unless you’re in an area with very low prevalence, wearing a mask reduces the risk of breakthrough infections. 18/

Being vaccinated is still the key. It gives us our lives back. But there’s no need to stop there. 19/

Monday’s @inthebubblepod has critical details with @EricTopol.

That sets up an exclusive 2 part conversation beginning Wednesday with Pfizer’s CEO that goes deep into the data & the 1300 questions you sent me. /end

https://twitter.com/aslavitt/status/1419494890883350532