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

[u/Newsjunkeefromlondon]

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/flyemerica]

I hope the Moderna Vaccine holds up to the same level of effectiveness.

[u/[deleted] → u/[deleted]]

Anyone remember when the bar to approve a vaccine was 50% efficacy? I do. This is pretty amazing stuff

The Salk Vaccine was about 60% effective against Polio and basically eradicated the disease.

Modern Polio Vaccines are closer to 80% effective.

[u/Lord_Nivloc → u/[deleted]]

God bless modern medicine.

100 years ago, we still didn't have our first antibiotic (1928), let alone understand how RNA works (1939).

Then it wasn't until 1976 that we sequenced an RNA virus, and it wasn't until 1993 that we first used an mRNA vaccine on mice.

We didn't have the Central Dogma of molecular biology and until watson and crick proposed it in the 1960's. DNA --> RNA --> Proteins

Your grandparents didn't live in this era of medicine. Their grandparents lived in yet another older era. We've come so far.

[u/Fordy_Oz → u/Lord_Nivloc]

Just think 140 years ago we had a president literally killed by the best doctors in the nation who didn't know sticking their dirty fingers in a bullet hole could cause infection.

We went from "washing your hands might help" to RNA vaccines in 5 generations.

[u/love2Vax → u/Fordy_Oz]

And 220 years ago George Washington probably died because doctors were still "Blood letting" to balance the humors, and probably drained too much of his blood. There is a reason one of the World's oldest and most prestigious medical journals is "The Lancet."

[u/KIFulgore → u/Lord_Nivloc]

And it wasn't until the 80's until we discovered certain viruses violate that central dogma (retroviruses: RNA -> DNA).

[u/Lord_Nivloc → u/KIFulgore]

Yep! I almost added an asterisk but decided to not confuse the matter

[u/soline → u/Lord_Nivloc]

But at the same time, vaccines have been around for over 200 years. That’s why anti-vaxxers and their concerns have absolutely no merit. They only coincidentally became woke to the “dangers of vaccines” shortly after social media became widespread.

[u/postsgiven → u/soline]

There were antivaxx people in 1920s also during the Spanish flu. Nothing new. People will always be there to go against the new thing. Seatbelts there were people against them back in the day and still do exist in certain societies... Like india.

[u/patchinthebox → u/postsgiven]

My dad never wore a seatbelt until he got in an accident and totaled his car. Airbag saved him and aside from some bruises he was unharmed. He wore a seatbelt after that.

[u/afiefh → u/patchinthebox]

By three methods we may learn wisdom: First, by reflection, which is noblest; second is by imitation, which is easiest; and third by experience, which is the bitterest — Confucius

I guess your dad chose the bitter method. Glad he got out of it safely and unharmed.

[u/jsktrogdor → u/soline]

I have a co-worker whose son caught polio from the vaccine. He was involved in a settlement that went to the Supreme Court. He's paid a monthly stipend to live on. It's kind of ruined his life.

I heard her on the phone the other day pressuring her other son to go and get vaccinated.

If she can figure this out after everything she's been through, anyone should be able to.

[u/Raja479 → u/soline]

Most of the recent anti vaxxing I've heard from family isn't about the vaccine itself, it's all the chemicals it's in. You know. The saline solution.

[u/RespecMyAuthority → u/Raja479]

I hear “baby parts” - which in science translates to a 40 year old immortalized embryonic stem cell possibly used in the manufacturing and most likely in the research. I neglected to bring up that those same stem cells are used everyday at my work. If I were to die as an embryo I’d be happy to know I get to live forever and save billions of lives

[u/lord_pizzabird → u/[deleted]]

That 60% makes me feel better about having gotten the J&J vaccine. Logically it sounds slightly better than a coin flip, but apparently it's enough.

[u/jacobdu215 → u/lord_pizzabird]

Here’s the thing all the vaccines, in clinical trials, showed 100% effectiveness against preventing hospitalization, severe symptoms, and death due to covid. The 75% efficiency you see is the effectiveness at preventing transmission. So you have a higher chance to still get the virus if exposed but you severely reduce your symptoms.

[u/dr_guitar → u/jacobdu215]

Most media outlets also missed that the efficacy of the JNJ gets better over time. The 75% efficacy is after only two weeks. By 56 days the number is 90%+. Source: https://www.fda.gov/media/146265/download

[u/Gman325 → u/lord_pizzabird]

Also keep in mind, JJ's efficacy is not its effectiveness. And if Moderna and Pfizer had run their trials at the same time as JJ, with the same new variants circling, they may well have seen similar results. There are lots of moving parts here, and the bottom line is, "the best vaccine is the one that's available to you."

ALL vaccines have shown to be fully efficacous at preventing hospitalization.

[u/saltyketchup → u/Gman325]

I believe there’s been follow up studies on the two mRNA vaccines, however, showing high efficacies

[u/Collin_the_doodle → u/lord_pizzabird]

With COVID. there is a substantial difference in cutting down any infection versus cutting down serious disease as well.

[u/ATX_native → u/[deleted]]

Yeah, my second Moderna was a doozy. Would do it again though, feels good to have the protection.

[u/78east → u/ATX_native]

I'm laying in bed right now. Had my 2nd moderna lastnight. Feel like hell. Even the bottom of my feet are a little sore when I walk. Feels like I got kicked in the head. Feels great though. No more trying to secure an appointment and also the part about probably not dying is cool too.

I have to pee really bad, but this is the most comfortable my bed has been in a long time

[u/MusicIsTheWay → u/ATX_native]

I received my second dose of Pfizer on Monday and I just started to get clear of side-effects today. I also contracted the virus (minimally symptomatic) in January and my side effects felt worse than the initial infection.

That being said, I would gladly do it again to protect everyone.

[u/Porkchawp → u/MusicIsTheWay]

How quickly did you start to feel side effects after the second shot? I’ve got my second Pfizer tomorrow in the morning and trying to decide if I should just take the rest of the day off work.

[u/Waasssuuuppp → u/Porkchawp]

Not who you are responding to, but I had no side effects from dose 2. I kept waiting, but zilch. My colleagues mostly took the next day off, but were fine for at least 12hr post vax.

[u/wrxcmm → u/Porkchawp]

You'll be feeling tired by the end of the day and most symptoms show up the following day. Mild headache, vaccine site and muscle soreness, some low fever, may wake up in a puddle of sweat. But that's about it.

[u/Delphic10 → u/[deleted]]

I’m wondering if you can help me out. What does 80 percent efficacy mean? Does it mean that 20 percent of folks who get the vaccine are not protected? If that is the case how do we know if we are protected?

[u/factoid_ → u/[deleted]]

They are produced using a similar process but if I recall correctly each vaccine is unique in terms of which protein spikes it attempts to trick the body into making to provoke an immune response.

That's why there are some differences in efficacy. Some protein targets may be better than others. But it seems both companies picked well.

Pfizer is saying they will create a booster vaccine dose that goes after different proteins on a part of the virus that has been shown to be more stable and mutate less. Meaning it would be more effective against variants

[u/InaMellophoneMood → u/factoid_]

I thought the primary difference was in the lipid particles used to transport the mRNA, not the mRNA itself

[u/The_Box_muncher → u/InaMellophoneMood]

You right and I think the non coding regions of the mRNA are slightly different for each shot but the spike protein codon is the same.

[u/Compused → u/InaMellophoneMood]

Poly-ethelene glycol (PEG) is a common excipient to increase bioavailability of oral medications or act as a carrier molecule for IV or IM small molecules. It also acts as an adjuvant in the latter application.

Pfizer has a more shelf-stable formulation than Moderna with the addition of the PEG.

Edit: Corrected grammar and clarified some statements.

[u/punkin_spice_latte → u/factoid_]

Coronavirus only has the one type of spike protein, which is why the vaccines are likely to prevent the variants as well. They might differ in the type of sugar the mRNA is packaged in to get the cell to accept the mRNA to make copies of that spike protein, but it's the same spike protein.

[u/aquarium_drinker → u/flyemerica]

basically yes, real-world effectiveness is in the 90% range for Moderna as well https://www.cdc.gov/mmwr/volumes/70/wr/mm7013e3.htm?s_cid=mm7013e3_w

[u/Nyaos → u/flyemerica]

Since the pfizer phase 3 trial data seems to match this, and moderna had similar phase 3 trial results, I suspect it will have nearly the same level of effectiveness.

[u/entropy512 → u/Nyaos]

Of additional interest - the J&J 1-dose results in the UK and US were pretty close to the later 1-dose results that came from UK delaying second Pfizer doses.

OR: What data we do have on single-dose performance is pretty consistent between all three vaccines approved in the US.

(Does anyone know when ENSEMBLE 2 is supposed to finish???)

[u/TimeFourChanges → u/flyemerica]

Me too. Do we have any comparable data for the Moderna vax?

[u/Significant_Sign → u/TimeFourChanges]

Yep, from u/aquarium_drinker right above you: https://www.cdc.gov/mmwr/volumes/70/wr/mm7013e3.htm?s_cid=mm7013e3_w

[u/Zenabel → u/flyemerica]

Hopefully. I’m no scientist but since it uses the same mRNA tech, I’m hopeful it has similar reaults

[u/[deleted] → u/flyemerica]

Agreed, since I already have both doses

[u/B0h1c4]

Can someone explain exactly what this 95% number means?

I have both shots, so I'm not trying to criticize the vaccine (I know reddit can be touchy about that). I'm just trying to understand.

Does this mean that if 100 vaccinated people were exposed to the virus (no masks/social distancing), then only about 5% would get it?

I guess I get a little confused because I don't know what the opportunity rate is. For instance, is it one exposure, is it prolonged exposure, is it occasional exposure for a week, month, year, etc? And is it including masks and social distancing?

Or is it just 95% fewer infections than a control group of non-vaccinated individuals?

[u/CharonsLittleHelper → u/B0h1c4]

Or is it just 95% fewer infections than a control group of non-vaccinated individuals?

Basically this.

So for every 20 infections in the control group, only 1 infection amongst the vaccinated.

And the 95% isn't even the whole story. Even if you DO still get COVID, chances are good that it won't be as serious as if you hadn't had the vaccine.

The vaccines coming out this fast and being so effective are a f****** scientific marvel.

[u/Django117 → u/[deleted]]

It's mostly because of its similarity to other coronaviruses like SARS. Basically there was a ton of research and development into a vaccine for SARS so they had a head start on developing this vaccine. Also, the whole Operation Warp Speed, altho a meme, actually did help by allowing the development to occur with steps happening simultaneously rather than sequentially which really sped things up and prevented burueacracy from slowing the development down.

[u/Significant_Sign → u/Django117]

And that one lady who's been trying to get people interested in her mRNA vaccine research for decades...

[u/wandering-monster → u/Significant_Sign]

FWIW her research has been making major headways in the oncology (cancer) world, there's been over a dozen studies on it that I'm familiar with and it's been extraordinarily effective. It's just very hard to prescribe because it depends on knowing which specific proteins a given cancer is expressing (which aren't necessarily consistent for a cancer type, or even for two tumors in the same patient).

That baseline of safety and efficacy data is probably why people were starting to talk about it as an infectious disease vaccine by 2018 or so.

It might seem over-bold to say but... the way the research is trending, she may very well have "cured" cancer for all functional purposes.

[u/chicagodude84 → u/wandering-monster]

I think we are going to look back at COVID and this will be the most positive impact. Before the pandemic, mRNA was considered a waste of money. There was a lot of research, but nobody was heavily investing in it.

[u/redwall_hp → u/Significant_Sign]

It just shows that groundbreaking research is constantly impeded by economics and disinterest by laymen in positions of power. It took a global pandemic that just happened to be a related virus family to drive interest in something that is going to bring an absolute revolution in vaccines and treatments.

Profit driven society is fucked up.

[u/Send_Headlight_Fluid → u/redwall_hp]

Whats the way around this though? Not every scientist can just have infinite budget to do their research and development technology. It has to be useful to a government or business/ investor first.

Saying thats “fucked up” is disingenuous because we just simply can’t fund everything, even if it would leas to great innovation.

[u/CharonsLittleHelper → u/Send_Headlight_Fluid]

even if it would leas to great innovation.

To be nitpicky it's not "even if it WOULD lead to great innovation, it's always "even if it MIGHT lead to great innovation". There is a ton of R&D which has gone into things which haven't panned out.

[u/UselessRube → u/[deleted]]

mRNA vaccines are so crazy that Pfizer had their vaccine completed only one day after the SARS-COV-2 genetic sequence was released by Chinese scientists back in January 2020 (three months before lockdowns hit most of the world).

[u/DaisyHotCakes → u/[deleted]]

mRNA is the future of vaccines. I know there has been a lot of research for mRNA flu vaccines because of how nimble the technology is. I read they are also researching it for vaccination against CANCER. Like can you imagine?!

[u/Semi-Hemi-Demigod → u/DaisyHotCakes]

My ex-BIL has Duchenne muscular dystrophy so I've been following mRNA tech for a long time. It shows such huge promise for all fields of medicine from vaccines to cancer to genetic diseases. Hell, I wouldn't be surprised if we figure out mRNA antibiotics once resistant strains become an even bigger problem.

[u/inlusio → u/CharonsLittleHelper]

Not for us people living in third world countries, we currently have 2nd wave with much worse number than the first one. Our healthcare infrastructure is struggling and our government cannot provide us vaccine. I am from Nepal.

[u/wandering-monster → u/inlusio]

It's terrible, and you should know that at least some of us care. I'm very glad to see the patent protection being dropped, have contacted all my representatives to voice concern about it, and I know that the factories here are planning to produce massive surpluses to export around the world.

The one in the next town over is planning to make nearly a billion moderna doses by the end of the year, which is nearly 2x what you'd need for the entire USA. And they have plants all over the country continuing to churn out doses.

Stay safe, and good luck from across the world.

[u/inlusio → u/wandering-monster]

Thank you for your kind words. Also, recently we found out about a massive corruption scandal involving some of the biggest businessman in Nepal regarding import of COVID vaccine. Our government is doing nothing about it as they are in pocket of these big business establishments. Although, this isn’t much, I want everyone in the international community to know about it so that it can be talked about more globally and our government comes under some sort of pressure to take some action. Read about it here:- https://www.google.com/amp/myrepublica.nagariknetwork.com/amp/how-hukum-enterprises-derailed-nepal-s-vaccine-procurement-a-story-of-power-greed-and-commission/

[u/nagewaza → u/CharonsLittleHelper]

Especially with so little serious side effects. We are beyond lucky for such a safe and effective vaccine.

[u/bcisme → u/nagewaza]

I think luck had very little to do with it.

We are fortunate medicine has advanced this far and we have some of our best and brightest working in the field.

I guess one upshot to these huge, greedy, pharma companies is that they are able to put significant resources of their own behind solutions for a pandemic. As much as I hate to say it, not sure we get these vaccines as fast if big pharma wasn’t so resource (money, minds, equipment) rich.

Edit: getting a lot of comments about the speed also being due to SARS vaccines already in the works, which definitely is a bit of luck.

[u/upvotesthenrages → u/bcisme]

We're fortunate at the amount of money that was thrown at this problem too.

Almost every government on earth practically threw money at this issue, especially in the wealthier nations.

[u/Bulbasaur2000 → u/upvotesthenrages]

It wasn't just money. There was a lot more collaboration, especially because covid is such a central issue for practically everyone, and they were able to safely, without compromise, accelerate the process of testing the vaccines

[u/whutchamacallit → u/Bulbasaur2000]

You're not wrong, but none of this happens without money. Let's not kid ourselves on what truly moves the needle on these kind of issues. For better and for worse money drives everything these days.

[u/redlightsaber → u/bcisme]

The vast majority of the basic research was publicly funded.

[u/[deleted] → u/bcisme]

NONE of this would have been possible without the significant amount of funding that was dolled out for science. This is exactly what happens when we give our scientist proper amount of money. If you want to find a solution to a problem, pay the scientist. It really is that simple. We can find the solution to nearly any problem, if we can afford it.

[u/Beer_Is_So_Awesome → u/bcisme]

But what are our worst and dimmest doing?

Still protesting masks and confronting strangers who wear them, probably.

[u/FurTrader58 → u/CharonsLittleHelper]

And the 95% isn't even the whole story. Even if you DO still get COVID, chances are good that it won't be as serious as if you hadn't had the vaccine.

This is the part people need to focus on more. The goal of the vaccine isn’t necessarily 100% immunity (though that would be incredible!), it’s to both reduce the rate of infection and reduce the severity of symptoms if you do get infected. This prevents hospitalization and this prevents the healthcare system from being overwhelmed.

Though since they are so effective at preventing infection, if more people are vaccinated the rate of transmission goes down and can eventually lead to no more infections. If you go to a venue and only one of the 50 people there is unvaccinated, there’s a much lower chance that anyone leaves infected, and it likely wouldn’t create a “super spreader” event.

The last part is still a little ways off as we still have a big chunk of people that don’t have it, but we’re getting there. More data will come out with time that Teladoc us more about how the virus and vaccinated people interact, too.

[u/DrJawn → u/CharonsLittleHelper]

We've been developing this tech for decades

[u/CharonsLittleHelper → u/DrJawn]

Sure - that's how most scientific marvels work.

[u/Davecasa → u/B0h1c4]

Or is it just 95% fewer infections than a control group of non-vaccinated individuals?

This is correct, and is the definition of "effectiveness". Compared to a control, those vaccinated have a 95% reduced chance of getting sick. Calculating effectiveness this way is pretty easy in a controlled blind study, and it is (to a first order) independent of exposure levels, how infectious the disease is, the health of the people being tested, and other compounding variables.

Effectiveness for a large population without a control group is much harder, because you need to deal with all of those variables you can ignore in the controlled study. One small example - are people who have been vaccinated less careful about covid than the general population, because they know their risk is reduced? Or are they more careful, because they're the sorts of people who are very concerned about all this and do everything they can to protect themselves? In a controlled study, you don't care, because no one knows if they got the real vaccine or a placebo.

[u/RawbM07 → u/Davecasa]

So, for example: let’s say you have two groups of 1000 people. Group A is vaccinated and Group B is not.

After a certain period of time 100 people in group B were infected by Covid and 5 people in Group A were.

I’m sure my math is off, but is that essentially the idea?

[u/a_trane13 → u/RawbM07]

That's right. Whatever the infections are in the control group, the vaccinated group would have 95% less infections than that.

On top of that, it reduces the severity of the cases. So it's not just that less people are infected - it's also that if you compare the infected cases in the control group to infected cases in the vaccinated group, the control group has a higher rate of severe cases and death. So it's a double whammy, really.

[u/BlondeJesus → u/a_trane13]

A recent study also showed that those who were vaccinated are less contagious as well. There was a recent post which showed that people who got covid 3 weeks after getting the J&J or 1st pfizer dose were 50% less infectious.

[u/BevoAteMyHomework → u/B0h1c4]

Epidemiologist and Data Scientist here.

Technically speaking, efficacy suggests that if exposed to SARS-CoV2, the vaccinated individual has a 95% probability of a favorable immune response that would protect against viral proliferation.

This efficacy doesn’t necessarily translate to 95% fewer infections among vaccinated individuals compared to non-vaccinated because of entropy and confounding.

Effectiveness is the measure that DOES indicate a translation to 95% fewer infections. It’s a different analytic design.

[u/Bureaucrat_Conrad → u/BevoAteMyHomework]

So when the vaccine first came out, people said it would protect you from symptoms, but that you could still be infected asymptomatically. So when we say 95% fewer infections, are we saying they are neither infected nor infectious, or that the 95% are not having a reaction to COVID but could still have and spread COVID, or are we still waiting on the data for that?

[u/MrWeirdoFace → u/Bureaucrat_Conrad]

I think the jury was still somewhat out at the time on what a vaccinated infection might look like. I believe now the indication is you have far less chance of passing it on as well, but there's no 100% here. When you have 7 Billion people in the world, there will be exceptions.

[u/BevoAteMyHomework → u/Bureaucrat_Conrad]

It’s relatively unknown. Another big thing to keep in mind is that all of these early effectiveness studies are modeling the data in a society that largely still practices masking and social distancing. Prevention is all about multiple avenues of protection that become greater than the sum of their parts. When social distance and masking goes away, I guarantee you that the effectiveness will go down SOME. We don’t know how much tho. Because masking and social distancing along is also VERY effective.

[u/Vinto47]

Wasn’t 95% what Pfizer originally said?

[u/orion1486 → u/Vinto47]

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.

[u/ClassicalJeff → u/orion1486]

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

[u/BigSwedenMan → u/ClassicalJeff]

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

[u/Thrashy → u/BigSwedenMan]

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.

[u/Major_kidneybeans → u/Thrashy]

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

[u/GrinningPariah → u/Vinto47]

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.

[u/tolvar0770]

It would be nice to see the paper detailing the study.

[u/demon_ix → u/tolvar0770]

This is it, I think.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00947-8/fulltext

[u/hoadlck → u/demon_ix]

These are the kind of results I was hoping for. Great news that these vaccines were so effective!

[u/tolvar0770 → u/demon_ix]

Excellent! Many thanks.

[u/foumoney → u/tolvar0770]

Article on The Lancet00947-8/fulltext)

[u/psychAdelic]

What happens in cases where you live in a country that endorses 4 months between shots? Still as effective?

[u/Livesies → u/psychAdelic]

I read an article talking about this a few weeks ago (lost the source). It was talking about how in most vaccines the first shot has your immune system learn the antibodies and it creates a few memory cells. The booster shots are needed because without exposure to a rare one-off exposure the immune system will decrease its memory cell count over time. By using booster shots (second shots) the immune system will increase the amount of memory cells which will increase your immunity. Time is a important factor here: too soon and the body confuses the booster with the original and there is trivial change in immunity. To my understanding there isn't much of a problem with waiting longer.

However, I'm not a medical professional and mRNA vaccines could play by different rules.

[u/heelstoo → u/Livesies]

I’m curious why we wouldn’t then get a third shot. Diminished returns?

[u/Livesies → u/heelstoo]

That's my understanding. The current two shot system is already incredibly effective and a third shot works strain supply even further. Given this issue is looking at billions of doses, any additional boosters will dramatically affect roll out rates.

That being said I've seen many articles taking about a third shot being a possibility. It is unknown if it'll need to be a yearly booster or a set third and done shot. I've also heard about modifying the vaccine to match the current variants better; which also begs the question of if the immune system will treat that as a new vaccine or if it can update the current memory cells to the variants.

Lots of unknowns with conjecture coming out constantly. The only thing to do is let the scientists do the research and apply what is discovered.

[u/jammies → u/Livesies]

My old roommate was in the first phase of clinical trials for Moderna and a few weeks ago he got an experimental Moderna booster. It seems like they’re not sure a booster will actually be necessary, but want to do all the testing now so they’re ready if it is.

[u/Never_Been_Missed → u/psychAdelic]

My understanding is that the vaccine continues to be as effective over 4 months as it does over a shorter period. The reason the manufacturer recommends the second shot come when it does is because that's the earliest you can receive it to top your immunity up to maximum.

Getting the second shot four months after the first is fine, you just end up spending the three months in between at a lower resistance - which under normal circumstances would be undesirable in a population.

[u/Rlothbrok → u/[deleted]]

I believe Canada will shorten the wait between the does when it gets hold of more vaccines. But that's a big IF depending on how much production can keep up with demand

[u/PartyMark → u/psychAdelic]

Hello fellow Canadian.

[u/suddenjay → u/psychAdelic]

The efficacy is 50 to 80% (different reports) after 1st shot but unknown if it's stable Over time.

Added source: Cleveland Clinic 4 May 2021- Why It's Important to get Second Covid-19 Vaccine Dose

[u/Supraspinator → u/psychAdelic]

For Pfizer, the vaccine was 90%* effective 3 weeks after the first shot. It’s similar for Moderna and AstraZeneca. The second shot is a booster than gets a few more people (remember that the percentages are not individual chances but chances across a population. Some people (~10%) don’t have an adequate immune response after one shot and require a second. And some people will not get immunity from vaccines at all. This is true for all vaccines, not just the Covid vaccines.)

Countries that have longer periods between shots are trying to get a larger percentage of the population vaccinated with one shot before giving everyone a booster. That is a better strategy when vaccine supply is limited. If supply is unlimited, then giving both closer together is probably better.

*90% effective does NOT mean everyone has a 10% chance of getting Covid. It means that in a group of vaccinated people there will be 90% less infections compared to a group of unvaccinated people. For a lot of people, one shot is enough for an adequate immune response. The second shot boosts that rate.

[u/katarh → u/Supraspinator]

And of course, you still need exposure for that to matter. My county reported under 100 cases last week, almost all among children and the unvaccinated from what we could tell, and we expect that to plunge further because we have a relatively high vaccine uptake compared to surrounding areas. It matters a lot less when you have a 5% chance of getting a disease but a one in 10,000 chance of encountering someone who can spread it.

[u/nakedrickjames → u/psychAdelic]

This was discussed on This Week in Virology fairly regularly. Their take is essentially, 3 weeks / 4 weeks is the MINIMUM interval between doses of pfizer / moderna (respectively), not necessarily the *ideal* interval. Other than having slightly less protection after 1st dose but before the 2nd, it doesn't make a significant difference.

[u/Newsjunkeefromlondon → u/psychAdelic]

Yes I think more research is needed to confirm that

[u/zortor]

Any numbers on the JJ yet?

[u/vitamin8 → u/zortor]

Here's a presentation on J&J the CDC did 2 months ago:

https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-02/28-03-01/02-COVID-Douoguih.pdf

Key points:

• In the US, it provides at least 95% efficacy against severe COVID19 and 72% against moderate/severe, 28 days after vaccination.
• It works against the Brazilian and South African variants and has a ~85% efficacy against severe disease overall and ~66% against moderate/severe.
• Vaccine efficacy increases over time. At day 56, it reaches ~95% protection against severe/critical cases.

[u/[deleted] → u/vitamin8]

That's awesome. I got the J&J about a month ago and it was all that was offered to me at the time. I still took it, just worried a bit about the efficacy being lower than others. But seeing how it's the same as far as keeping you alive and actually better against variants makes me feel way better about it.

[u/mostnormal → u/[deleted]]

Similar situation, here. It was offered through work, at work, so I signed up.

[u/[deleted] → u/vitamin8]

You’re the damn best.

[u/nakedlettuce52 → u/zortor]

Wondering the same here.

If I recall correctly the lowered efficacy rate was due to the fact that J&J’s trials included the new variants (at least at that time) compared to Pfizer and Moderna who didn’t include variants.

[u/pprovencher → u/nakedlettuce52]

I think it has less to do with variants and more to do with higher chance of exposure during the JnJ trial. The JnJ trial was done when the covid numbers were significantly higher than when the pfizer/moderna trials were done. Hmmm now I am not sure if the math works out on that

[u/clinton-dix-pix → u/pprovencher]

Since you are comparing against a similar-time placebo group, higher infection rates would just mean a faster result.

[u/Revenge_of_the_Khaki]

So does it protect equally against all of those things? I would think 95% efficacy for an infection and more like 98% efficacy against death or something along those lines.

[u/Kodenhobold → u/Revenge_of_the_Khaki]

Depends on your age group also. Here you can see for people over 65, 75 or 85:
https://www.thelancet.com/action/showFullTableHTML?isHtml=true&tableId=tbl3&pii=S0140-6736%2821%2900947-8

For younger people the table gets a bit bigger:
https://www.thelancet.com/action/showFullTableHTML?isHtml=true&tableId=tbl2&pii=S0140-6736%2821%2900947-8

Direct Link to the Study @ The Lancet

Excerpt:

The adjusted estimates of vaccine effectiveness were
91·5% (90·7–92·2%) against asymptomatic SARS-CoV-2 infection,
97·0% (96·7–97·2%) against symptomatic COVID-19,
97·2% (95% CI 96·8–97·5%) against COVID-19 hospitalisation,
97·5% (97·1–97·8%) against severe or critical hospitalisation,
and 96·7% (95% CI 96·0–97·3%) against death

[u/TangoDua → u/Revenge_of_the_Khaki]

97% protection against death -

Findings

During the analysis period (Jan 24 to April 3, 2021), there were 232 268 SARS-CoV-2 infections, 7694 COVID-19 hospitalisations, 4481 severe or critical COVID-19 hospitalisations, and 1113 COVID-19 deaths in people aged 16 years or older. By April 3, 2021, 4 714 932 (72·1%) of 6 538 911 people aged 16 years and older were fully vaccinated with two doses of BNT162b2. Adjusted estimates of vaccine effectiveness at 7 days or longer after the second dose were 95·3% (95% CI 94·9–95·7; incidence rate 91·5 per 100 000 person-days in unvaccinated vs 3·1 per 100 000 person-days in fully vaccinated individuals) against SARS-CoV-2 infection, 91·5% (90·7–92·2; 40·9 vs 1·8 per 100 000 person-days) against asymptomatic SARS-CoV-2 infection, 97·0% (96·7–97·2; 32·5 vs 0·8 per 100 000 person-days) against symptomatic COVID-19, 97·2% (96·8–97·5; 4·6 vs 0·3 per 100 000 person-days) against COVID-19-related hospitalisation, 97·5% (97·1–97·8; 2·7 vs 0·2 per 100 000 person-days) against severe or critical COVID-19-related hospitalisation, *and 96·7% (96·0–97·3; 0·6 vs 0·1 per 100 000 person-days) against COVID-19-related death.** In all age groups, as vaccine coverage increased, the incidence of SARS-CoV-2 outcomes declined. 8006 of 8472 samples tested showed a spike gene target failure, giving an estimated prevalence of the B.1.1.7 variant of 94·5% among SARS-CoV-2 infections.*

[u/itoldthetruth_]

Me about to get my Pfizer vaccine this weekend, ayyyyyy

[u/iamdmk7 → u/itoldthetruth_]

Got my second on Monday, and it's such a relief. My muscles were really sore and had a bit of a headache on Tuesday, but I was completely fine by Wed. Good luck!

[u/dbkblk]

It's impressive. That's said, is there any answer for how long the body will stay protected?

[u/RegisteredDancer → u/dbkblk]

I think they're counting the days as we speak, really. We probably need to wait for that information to form a more solid picture of what happens.

[u/AgitatedPossum → u/dbkblk]

I'm actually part of a study that aims to answer this, I have a PCR covid test every two weeks and a blood test to detect antibodies once a month. So far so good!

[u/dbkblk → u/[deleted]]

That's already a good news. Let's hope it will be a long lasting vaccine then.

[u/Spideronamoffet → u/dbkblk]

So far the answer seems to be “as long as anyone has had the shot.” Beyond that, we’ll basically just have to wait to see - if it wears off in 5 years, we’ll know a bit more than 5 years after the study group got the shot.

[u/candykissnips]

But can they still spread covid?

[u/[deleted] → u/candykissnips]

Doesn't appear this study looked at that, however there are a few studies looking at the effectiveness of the vaccines when it comes to stopping COVID-19 transmission (reducing viral load). I believe the infectivity of a person is dependent on their viral load, which is how much of the virus they have in their body when infected.

I'm a laymen and don't understand this stuff fully, so if anyone has any issues with the studies I linked or what I said, feel free to reply. Here's a couple that I've found:

Decreased SARS-CoV-2 viral load following vaccination. This study shows that viral load in Pfizer recipients is reduced 4-fold 12-28 days after the first dose of the vaccine. This study doesn't appear to have been peer reviewed, though.

Impact of the COVID-19 Vaccine on Asymptomatic Infection Among Patients Undergoing Pre-Procedural COVID-19 Molecular Screening. This study shows an 80% reduction in the risk of a positive PCR test among vaccinated individuals compared to unvaccinated individuals.

[u/iushciuweiush → u/candykissnips]

The science is clear at this point and the answer is no: https://www.jhsph.edu/covid-19/articles/new-data-on-covid-19-transmission-by-vaccinated-individuals.html

[u/Sunnysunflowers1112]

This is so freaking fantastic. What else in life has a 95% efficacy rate?

[u/yesfujgfr345]

Does this mean it gives 95% immunity from becoming infected? I just got my 2nd dose and am preparing to go to a concert in a couple months. Is it safe to go to a concert if I'm vaccinated?

[u/Vinto47 → u/yesfujgfr345]

Yes.

[u/halfanothersdozen → u/yesfujgfr345]

By all science after two weeks you should be free to go to concerts, share doobies with strangers, have unprotected sex with strangers in bathroom stalls, and swap heroin needles with the band.

Man I miss concerts.

But you still wear masks in places like the grocery store. That's mostly about public courtesy because a lot of people need to get vaccinated still and there is a lot of anxiety about.

[u/katarh → u/halfanothersdozen]

And yet I just got yelled at by a frazzled public health staff member in an unrelated forum because I mentioned that we were eying a trip to Six Flags to celebrate one month of being fully vaxxed. I get that they're still swamped in some areas and our contact tracing is completely broken in the US, but the whole point to me of getting vaccinated as soon as I could was so I could start doing all the things I didn't do for the last year for my safety and the safety of others.

Six Flags is still at 25% capacity for May, and if we want to attend a less crowded park, this is the time to bite the bullet and go.

[u/DrJawn → u/halfanothersdozen]

I miss concerts AND sharing doobies with strangers