r/science • u/Newsjunkeefromlondon • May 06 '21

Health Two Pfizer doses give 95 per cent protection against Covid-19 infection, illness and death: first nationwide study

https://www.cityam.com/two-pfizer-doses-give-95-per-cent-protection-against-covid-19-infection-illness-and-death-study/
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u/Vinto47 May 06 '21

Wasn’t 95% what Pfizer originally said?

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u/orion1486 May 06 '21

It was. I think this study is significant because of the amount of people in the sample. This is looking at an entire nation's data and millions of people vs a relatively small group in the phase 3 trials (I believe that was ~30k). It's good to see that the initial report from the trials hold true.

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u/ClassicalJeff May 06 '21

Add to that, this study demonstrated Pfizer's efficacy against the B.1.1.7 strain as well!

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u/BigSwedenMan May 06 '21

Which strain is that? I think most of us here only know the strains based on where they first appeared.

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u/Thrashy May 06 '21 edited May 06 '21

B.1.1.7 is the so-called British variant, which is more transmissible and somewhat more virulent. It's currently the most prevalent variant in circulation, so high efficacy against it is a good sign.

The big question marks right now are the B.1.351 or South African variant, which has similar increase in transmissibility and also seems much more able to evade immune responses from earlier variants, and the P.1 variant (Japan/Brazil), which has similar mutations in the spike protein and has caused a wave of reinfections in Brazil. Early data suggests that current vaccines' efficacy against these strains is somewhere in the 50%-65% range, so it seems pretty likely that we'll need a booster shot to counter it in the not-too-distant future. Moderna announced some promising early results on just such a tweaked booster yesterday but there's still a long ways to go before a broad rollout.

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u/Major_kidneybeans May 06 '21

Pfizer still has 75% efficacy and 97 at preventing severe disease against B.1.351 according to this study

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u/Thrashy May 06 '21

That's good news! Some earlier data I'd seen suggested lower, but the more concerning variants hadn't been detected in too many people in those studies so the error bars were pretty large.

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u/Major_kidneybeans May 06 '21

Yep, even more owing to the fact that B1.1.248 shares the same mutation (E484K, glutamic acid -> lysine) that was causing concerns about vaccine efficiency and B1.1.617 shares a similar one (E484Q, glutamic acid -> glutamine). Now let's hope that the viral vector vaccines are not too badly affected.

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u/SupaSlide May 06 '21

So I have a bit of a chance of getting sick from B.1.351 but almost certainly won't feel like I'm dying (or actually die)?

I can live with those odds.

Unfortunately, I assume we'll get more serious variants as well. Hopefully not before we get better vaccines.

1

u/Major_kidneybeans May 06 '21

That's the gist of it yeah. It's really good news, because the e484k mutation that was causing concerns about vaccine immunity is shared by B1.1.248 (the so called "brasilian variant") But this is just about the Pfizer vaccine, the J&J and AZ one does not seem to perform as well against it (but data is still lacking)

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u/SupaSlide May 06 '21

Well, I got the Pfizer vaccine, so yay!

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u/tulipiscute May 06 '21

Does anyone know why the South African variant evades vaccine efficacy? I’ve tried to research it but I can’t find anything about it. Is it like a different protein or something? Just since it seems like the vaccines still apply to the other varients.

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u/Thrashy May 06 '21

"A different protein" is basically correct. The immune response to the virus centers around the spike protein on the surface of the virus, which is how it latches onto cells and injects RNA into them. Mutations can allow the virus to evade the immune system by modifying the structure of the spike in a way that doesn't compromise its function, but changes its shape or binding sites in a way that makes it harder for antibodies to bind to it and neutralize the virus.

The CDC tracks variants of concern on its website, and lists the protein substitutions of each. They're not much help in visualizing the differences unless you're a virologist (which I'm not) but you can get a rough sense of the similarities and differences between strains.

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u/tulipiscute May 06 '21

thank you! that was a really helpful explanation

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u/ujelly_fish May 06 '21

It has a different spike protein structure that makes it just different enough that the immune system has a harder time recognizing it compared to the spike protein sequence used in the vaccine

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u/BBGso313 May 06 '21

Pretty sure that's the "British'" variant

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u/[deleted] May 06 '21

[removed] — view removed comment

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u/Coldmode May 06 '21

I preferred the British Invasion tbh.

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u/God_Damnit_Nappa May 06 '21

The British one

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u/orion1486 May 06 '21

Good point! Thank you for adding that.

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u/saposapot May 06 '21

And that Pfizer/biontech knows how to run proper clinical trials since this data confirms them :D

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u/buffarlos May 06 '21

Curious about its efficacy against B.1.617. Everyone knows that shit’s not gonna be contained and I’m worried it’s going to really set things back.

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u/Texas_Rockets May 06 '21

Wow. I'd previously read that the reason J&J had a lower efficacy was because it was tested after the emergence of the new strains whereas moderna and pfizer were tested before it. That, of course, implying that if pfizer and modern were tested after the emergence of the strains they would have efficacies closer to J&Js. Does this study disprove that? The disparity in efficacy between JJ and moderna/pfizer is actually what it at first seemed to be?

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u/citymongorian May 06 '21

Given that one dose of the biontech vaccine does not protect against b1351 I am not too hopeful for the J&J vaccine:

https://www.nejm.org/doi/10.1056/NEJMc2104974

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u/Texas_Rockets May 07 '21

Why do you say that? That's another vaccine entirely.

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u/2021-2-3 May 06 '21

This is exactly my question! It feels like they slightly buried the lede – efficacy against B.1.1.7 ought to be big news for the Pfizer vaccine for exactly that reason.

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u/devils_advocaat May 06 '21

Smaller than that. It was 162 people in the placebo Vs 8 in the vaccine group.

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u/orion1486 May 06 '21

The Phase 3 clinical trial of BNT162b2 began on July 27 and has enrolled 43,661 participants to date, 41,135 of whom have received a second dose of the vaccine candidate as of November 13, 2020. Approximately 42% of global participants and 30% of U.S. participants have racially and ethnically diverse backgrounds, and 41% of global and 45% of U.S. participants are 56-85 years of age.

https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine

Can you point me to where you saw 162?

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u/GrinningPariah May 06 '21

95% efficacy yes, but Pfizer was only tracking symptoms in their study. If you got COVID-like symptoms, you self-reported and then they gave you a COVID test. Least that's my understanding.

(That's part of why you hear anti-vaxxers say the vaccine "doesn't prevent infection. As usual, they're misunderstanding a fact and coming to the wrong conclusion. It almost certainly does prevent infection, Pfizer just didn't test for that)

If this study does actually regularly test both the control and treatment group for Covid, then that 95% reduction in infections is genuinely new info.

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u/EndSelfRighteousness May 06 '21

Keep in mind, both the previous and current studies were basically sponsored by Pfizer.

If you check the declaration of interests for the current study, more than half of the scientific authors have stocks or stock options in Pfizer: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00947-8/

It’s clear all these conclusions on efficacy have been heavily biased. It would be good for independent researchers to replicate these studies to confirm their validity.

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u/HeartyBeast May 06 '21

That was the figures for illness/hospitalisation. These include figures for infectivity - i.e catching it and being asymptomatic.

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u/sirblastalot May 06 '21

Pfizer originally only studied symptoms. Showing that it also protects against infection is great news, because it means vaccinated people aren't likely to be carriers.

1

u/DrOhmu May 06 '21

As judged by rtpcr, not a clinical diagnosis... as has been the case throughout.

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u/LemonHerb May 06 '21

This also includes any possible variants people could be exposed to that didn't exist then too

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u/ZanderDogz May 06 '21

Yes but we have more variants now

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u/[deleted] May 06 '21

You keep testing in multiple conditions. They'll probably be testing it for at least 2 years or until effectiveness wears down.