Two doses of Pfizer, AstraZeneca shots effective against Delta variant: study

Two doses of Pfizer, AstraZeneca shots effective against Delta variant: study


https://www.nejm.org/doi/full/10.1056/NEJMoa2108891 I believe this is likely the journal article referenced incase anyone wants to read it. It's always annoying how the news articles never provide links.




I find it even worse how often the 'clever journalist' misunderstands the science and when they try to explain the study they get fundamental things wrong about it.


There's a lot that's almost deliberately obfuscatory about this study and the reporting of it. Test-negative (using data from individuals who have presented to a medical facility to get tested, rather than from the wider population) designs with many adjustments for different groups when it is already assessing a self-selecting group mean that the results add to a picture of our understanding vaccine efficacy but they are far from the whole picture. It is possible that the original 60% figure may be closer to the true value for that vaccine just as much as the new 67% figure based on this study, which is not without its limitations. More research is needed, as always, sample sizes could be bigger, as almost always. I don't want to be doom and gloom about it but the plan seems to be to just to ignore it after putting all eggs in the one basket. Vaccines aren't a panacea for new diseases, they need to be applied along with a suite of sensible, workable and generous measures worldwide.


One thing I think that helps people to understand vaccines is to talk about them in terms of resistance. I think people think of vaccines as a shield that blocks out viruses or something. Vaccines are more like training partners for your immune system that help you fight the real infection should it come. The immune system doesn't always immediately recognize a new pathogen. In the case of Corona, it evades the immune system for a while allowing the viruses to replicate unchecked. Then once the immune system is tipped off it has a huge fucking mess to clean up. This is one of the reasons people can die from the cytokin storm. However, when you get a vaccine the immune system already has some experience in fighting (or building resistance to) the selected pathogen. This means the virus doesn't proliferate in your body unchecked. What it doesn't mean is that the virus never enters your body nor that it doesn't high-jack some cells. I think this is why some vaccinated people are concerned about breakthrough infections. Breakthrough infections are expected and most of them will be asymptomatic. This means you've caught the virus and the vaccine did its job in helping to prepare you to fight the infection, no symptoms though because you're golden. However, some infections become severe, and so far these are very rare. But, those who have a weak immune response to the vaccine can more or less expect that the 'training' the immune system went through wasn't as effective. This isn't because of the vaccine but rather due to a weakened immune system. This is why it is important for alllll of us to get vaccinated. Those who have weakened immune systems are really vulnerable to infection even with vaccines (although vaxx provide them some support). The more of us that are vaccinated the fewer reservoirs the viruses have to mutate in. And thus, we can head toward herd immunity to protect the more vulnerable. So take up your weapon (vaccine) in the fight against corona and help save lives! Be a vaxx-hero!


> but find somewhere to put a tiny citation. But wherever will they find the space amongst all the comment bins, recommended articles, trending lists, cookie requests and email newsletter offers? I'm hoping for a new wave of web design that makes us feel about the current wave what we do about the last wave of web design.


So you're saying you want a third wave...? On a more serious note, I'd suggest it's not really web design that's the problem - there are plenty of beautiful and functional websites out there from people who don't need to and/or aren't trying to squeeze every drop of revenue they can from their sites which prove that. What we might need, I reckon, is a model for the internet which is more commercially sustainable without so many sites needing to resort to the kinds of design decisions you're referring to. But even that might not really be necessary (i.e. it might already exist). Some sites put up a paywall, some sites cram ads in everywhere they can, some sites offer both models so you can choose, some make money elsewhere and don't try to monetise their website particularly or at all - am I'm sure there are more models out there already (Wikipedia, for example), and more to come. Just choose according to your tastes, I guess.


I guess I'll have to until news sites cotton on to my mewlings, which is my most frequently visited site type


It's annoying when trying to do research online and find something interesting and they don't even mention the names or places involved with the research - instead they're just "scientists". It could be researchers who are top class in their field or some complete nonsense they found on Facebook.


>clever clogs I hope one day some know-it-all in crocs lectures me on something so I can bust out the "calm down, clever clogs"


Honestly I'm 50/50 on this. Scientific articles are not for public consumption. They are ripe for misinterpretation - or at the very least not being able to spot the flaws in method that experts in that field can see. People could read a journal article that 'proves' vaccines are rubbish - if they don't understand the words, context and methods then they might believe it. I'm not convinced that is what we want. Journal articles are written for other experts, not for everyone, and that's a good thing.


Nice post, I couldn’t agree more. This is exactly what a lot of covid deniers do, and they truly believe that their ‘research’ is definitive and correct.


> Wednesday's study found that two doses of Pfizer's shot was 88% effective at preventing symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant, broadly the same as previously reported. > Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness. This is great news and even more reason to get both your jabs.


The AZ isn't quite as effective as I'd have liked given how long I've had to wait for my second dose of the bloody thing.


AZ seems to come out as less effective at preventing Covid, but equally effective at preventing hospitalisation and death.


i've heard this but what data do we have to back it up?


Not a very helpful answer, but "Various studies I have read." I had AZ, so I've been following it.


I've seen the same, just would liek to see something as detailed and respectable as the OP.


/r/Covid19 is a decent source for studies like this.


Yearly flu jab has an efficacy of 65% usually. 67% is more than sufficient.


You don't need to test negative for the flu to get on a plane. I have lots of friends and family on the continent I'd love to visit, but an infection and a positive test means potentially ending up stuck somewhere for days until I test negative. It's not very fair that some of us are at a much greater risk than others of getting infected.


If you look at [the source](https://www.nejm.org/doi/full/10.1056/NEJMoa2108891) the 95% confidence limits overlap, so while it's *likely* that AZ is less effective against delta, the data isn't strong enough to say so for certain.


It honestly explains why there are reports of people with 2 shots getting infected. Most of the fully vaccinated people are still over 40s, so they would have had AZ and not Pfeizer.


It's a numbers game. To be blunt, we fully expect some people who've been double-vaccinated to die of covid. It's just that that number should be significantly smaller than it would have been without the vaccines.


It's interesting that we don't mind double vaccinated people dying. When we could lockdown to save them.


We could also continue to see mental health cases spike and sectors of the economy seriously struggle. It's all about weighing up the two options.


I totally agree. But it's interesting that I've been properly abused for saying some deaths are okay. But now apparently some deaths are okay.


Pfizer was approved in the UK before Astrazeneca so it’s highly likely the most vulnerable groups received Pfizer as it was the first vaccine available and they were the first to receive vaccines


In in the UK and vulnerable - had my first shot in Feb. AstraZeneca. At the time I was just happy to be getting any shot but now I can't help but worry that I got the "shit" one and I won't be as protected.


I’m guessing you came under category 4? Not saying the categories were appropriate but I think the vast majority of the top 3 categories received Pfizer purely due to the timings of the vaccine approvals and vaccine rollout Any protection is better than no protection and if you do get COVID a vaccine should lessen any symptoms you experience with the whole goal being to keep people out of hospital


Not necessarily - my parents (70s) and Grandad (90s) all had Pfizer.


Kinda hard when you're told no before 8 weeks.


There's evidence to suggest that a gap of around 8 weeks provides the best immunity, to be fair. But obviously it's frustrating that everything has opened up, but younger people with one jab have relatively little protection.


I’d still rather have a bit less protection now than more protection later.


Until later comes.


Well, right now is a huge surge of Delta. At some point it’ll burn itself out, because the government’s plan is herd immunity by infection. I’d rather be part of the group with vaccine-acquired immunity. Later isn’t such a big deal especially if we all get booster shots at some point. Anyway it’s too late now, I’ve just had my jab.


> because the government’s plan is herd immunity by infection 8 months of intense vaccine rollout coulda fooled me.


What else do you call lifting all restrictions with cases about to surpass the largest peak so far, no-one under 18 vaccinated, and 31% of adults still without their second shot?


I'd call it a long time coming, personally. >no-one under 18 vaccinated It's not even clear we'll ever vaccinate that cohort. Current data shows vaccine to be more dangerous than COVID for children. >31% of adults still without their second shot? That'll change soon enough. Also, they're all in the less at risk age ranges, so who cares? Anyone who is still scared of COVID, and hasn't had their second jab, is free to hunker down for a few more weeks until the do.


> Current data shows vaccine to be more dangerous than COVID for children. That’s just a blatant lie, given what we now know about long Covid. I suppose it’s true that tens of thousands more people being blatantly murdered by this government’s ineptitude was a long time coming, though.


> That'll change soon enough. So...we wait until that *has* changed...


I'm 20 and got mine after 21 days about a week and a half ago. If you want it, it's out there. /r/GetJabbed is a great resource.


I’m literally standing in a queue about to get mine thanks to that subreddit :) Edit: jabbed 😁


the places near me have turned people less than 8 weeks away, but good for you enjoy the freedom


Thank you, although I'm not planning to enjoy freedom until we've essentially eliminated the virus in this country.


Same here, keep distancing and staying safe.


I work in the lower end of the covid “field” let’s say (lol) in which part of my job is telling people no when they’re coming to get their second dose before 8 weeks. It sucks because people think we are doing it for no reason where as we have to do it because it’s the government guidelines, and unlike GPs, local councils have to follow this. I feel bad a lot of the time because people get a text from their GP which confuses things a lot but there are reasons for the 8 weeks like max immunity and fairer distribution.


Thank you for doing your job. It's important and valuable wherever you are in the field and we appreciate it.


How do we define "effective"? If it's 67% effective what does that mean for the other 33%? Does that mean it's as good as having had nothing at all?


https://www.cdc.gov/flu/vaccines-work/effectivenessqa.htm 67% effectiveness= 67% of people vaccinated didn't get sick (from Covid) If a person is immunocompromised, then their immune systems won't 'take up' the vaccine as effectively, which means it is likely to be less effective when exposed to Covid IRL.


So 67% = don't catch it at all? Will there be some partial protection for the others? E.g. less severe cases etc?


> So 67% = don't catch it at all? Kinda. Given the same environment, your chance of catching it and developing symptoms is on average reduced by 2 thirds. > Will there be some partial protection for the others? E.g. less severe cases etc? Yes. In general: - The risk of catching it in the first place is reduced by a certain percentage - The risk of having to go to hospital for it is reduced by a larger percentage - The risk of dying from it is reduced by an even larger percentage.


Great thanks, that's comforting. 67% doesn't sound great but I guess the partial protection helps make up the difference significantly. I guess it would be useful for the stats to also reflect %risk of death improvement or %risk of hospitalisation risk somehow. Condition probably is inherently confusing to people though.


Yeah it'd be nice if it offered greater protection from symptomatic disease, but it's a lot better than nothing: and the main thing is that it protects you from getting a bad case of Covid or even dying from it pretty well. If I remember correctly, the last numbers from PHE were 92% protection from hospitalisation for AZ/Ox, 96% protection from hospitalisation for Pfizer/BT. So... pretty good. And I know this is risky territory because this sub is very anti on this topic: but that is why only admitting fully vaccinated people to things like night clubs makes perfect sense. Test results can be false negatives, people who are asymptomatic but vaccinated can still carry and spread the virus: either way there is no way to rule out that the virus gets inside the club. But the important distinction is the next step: if a lot of the people are unvaccinated, it means they will catch it comparatively easily, and become symptomatic with a much higher probability. Not only will they bear a higher risk of having to go to hospital, they are also more likely to spread the virus further. Essentially, Delta can burn right through that population - exactly what happened in the Netherlands ~2 weeks ago. But if everyone present is vaccinated, they are much less likely to catch it, they are less likely to spread it, they are less likely to take up resources in hospital, and of course they are less likely to die too. The vaccinations act as a damper on the spread, *and* make the spread itself much less dangerous. Get vaccinated guys. Please, so we can leave this bloody nightmare behind us and don't get back into the shit in autumn / winter.


Well said.


https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/how-they-work.html I want to preface this by saying I don't have a degree in Microbiology and I'm not a health care professional. Short answer: Yes, kinda. Long answer: A vaccine exposes you to the virus: either in an attenuated form (so it can't infect you/hurt you), or provides a sample of antigens (markers on the Virus Cells that tell your body that it's not a body cell- this is kinda how the Astrazenica vaccine works) or provides a sample of genetic material (mRNA- Pfizer) which produces an immune response. Your body responds like it's an actual infection, so it works out how to make antibodies which get rid of the immune response causing agents, and leaves plasma/memory cells which stick around in your blood stream. Edit: Memory Cells tell your body what to do if you're infected next time, so you don't have to go through the process again. The level of immunity you are left with depends on the effectiveness of the vaccine (high) and the ability of the body to respond to the infection and produce antibodies and memory cells. If it's not as good as a healthy adult then you'll have less immunity the next time you come in contact with Covid. You'll still have some, it'll just be less. So if it's 67% effective then 67/100 healthy (average) adults will have a strong immune response, show no symptoms. Symptoms occur when your body is responding to the virus (e.g coughing/sneezing is a way of trying to expel the virus after it's been 'caught' in the mucus membranes in your nose/throat). To do that you have to have a significant amount. If your body recognises Covid quickly, your immune system will get rid of it quickly and thus you'll have significantly less or no symptoms. So- yes you can still catch it and be asymptomatic, but you'll get a less severe form of the disease, depending on your personal immune response level/ if you're immunocompromised. I hope that makes sense!


The stats are measured on populations rather than individuals. Take 1000 unvaccinated and 1000 vaccinated people, and watch to see how many get infected. Let's say maybe 100 unvaccinated people get sick during the period you're doing the study, whereas only 33 vaccinated people do. We conclude that it prevented 67 out of what would have otherwise been a similar 100 infections in the vaccinated group: hence 67% effective. There's not enough information in that scenario to tell whether everyone in the vaccinated group had equal partial protection, or if there was some subset that were _completely_ protected while another subset failed to respond to it. You might be able to assess whether an individual has produced an immune response by testing them for antibodies, but that's not typically part of the effectiveness number being quoted.


It means 67% fewer people get sick among the vaccinated compared to the non vaccinated. Or, if you are vaccinated, the chances of you getting sick are 67% lower than the chances of a non vaccinated person to get sick. So if you and a non vaccinated person both got sprayed sars-cov2 in the face, the non vaccinated person will get sick for sure (well, almost), and your chances of getting sick in that case would be 33%.




This might no longer be the consensus, but aren’t the vaccines more effective if they’re spaced out (to an extent)?


Christ, remember how everyone was losing their absolute shit because the government changed to 12 weeks and not the 3 or 4 originally planned based on that result (and, I hope, more in-depth consultation with the researchers in question)?


Probably worth mentoning that the 3-4 week number was provided by the manufacturer and used in the trials. 12 weeks being "better" was more a happy coincidence rather than based on any actual data. The govnt just got lucky with that decision which was geared more towards getting more 1st jabs out of the door at a faster pace. I'm not complaining anyway.


Yes and no, most two dose vaccines work better and for longer if the two doses are further apart. The government tool a calculated risk that 12 weeks wouldn't have any detrimental effect and might even provide a benefit. Much as a dislike BoJo the Clown and his band of muppets this wasn't a completely science free decision.


I know people on this subreddit don't like to say anything positive about the UK but when it comes to the skill and professionalism of our doctors and researchers the UK are world leading. Shame our politicians for the most part aren't the same.


Well typically with vaccines, a 6 month interval between jabs is used. The only reason the trials used 3-4 weeks is because that's the absolute minimum and they needed results fast. So it really wasn't much of a gamble to go up to 12 weeks. And the media massively overstated the "outcry" against this decision. A few, including the BMA raised concerns, but nobody was saying, this is dumb.


Typically a vaccine booster will be spaced out months to years after the initial dose to help develop better memory. But it's a balance vs risk of infection. The 3 weeks gap for Pfizer many countries are doing is likely to provide poor long term memory IMO, but it got the company results quickly and hey more people to get a third injection, funny how it works out.


Struggling with this decision myself at the minute, second one due mid Aug but could bring it forward. Tough to know if better long term protection is worth the wait given increasing rates/chance of getting infected in the meantime


Personally I'd keep it if you're basically house bound until August but if you're planning to actually go out and be among people then bring it forward.


I think 8 weeks plus is meant to be OK. Doesn't have to be 12. But 3 isn't ideal afaik


From what I've seen, 8 weeks is around the best time (and also the minimum you're allowed in the UK)


You imply that there's an ideal timing that is the same for all two-dose vaccines. Do we know if that's the case? For the covid vaccines it was just limited by what they originally tested.


>You imply that there's an ideal timing that is the same for all two-dose vaccines. Do we know if that's the case? There's no one ideal timing, but for every well-established adult vaccine the time before needing a booster is months if not years. The only exception I'm aware of is the Rabies vaccine, which is unique in several ways. Generally you want the booster to really trigger response from immune cells, so you want the initial immune response to the first jab to have fully died down. >For the covid vaccines it was just limited by what they originally tested. Indeed, it's not optimised.




Are you familiar with affinity maturation? Many epitopes of the spike protein have also remained very highly conserved between variants.


Covid-19 is not a rapidly mutating virus by any stretch. Most RNA viruses have high mutation rates, but coronaviruses are notable because they are an exception to this rule. Influenza, for example, mutates at double Covid-19's rate.


As far as I'm aware the study supporting this had very low sample size and was only of people over 80


No, real world data from our vaccination programme has now proven it correct. 12 week gaps provide better protection than the 3 weeks of the original trials, across all vaccines. Literally tens of millions of data points.


Show me the study and I'll change my mind!


Such a study is literally the topic of this post we are all commenting about....


I thought this was just talking about effectiveness vs delta, not length of time between vaccines for effectiveness, and what that could mean for our exit strategy?


This isn't true. The reason why the 12 week gap were introduced were to get as many people as possible vaccinated with 1 jab as 1 jab is better than none. There is zero data upholds the 12 weeks. My Girlfriend has had her 1st jab last week, she has been told she can come back as early as 3 weeks but they recommend to her to wait until 6 weeks then come back. That is for the Pfizer jab so if 12 weeks were proven to be better then why tell her to come back after 6 weeks?


https://www.livemint.com/news/india/astrazeneca-submits-trial-data-for-8-12-week-interval-between-covishield-doses-11613056630569.html From Feb, lmao. >The primary analysis of the Oxford-led clinical trials from the UK, Brazil and South Africa confirmed that it was 100% protective against severe disease, hospitalization and death, more than 22 days after the first dose, 76% efficacy three weeks after the first dose that is maintained to the second dose. Efficacy increased up to 82% with longer inter-dose interval of at least 12 weeks or more, the company spokesperson said. 'Zero evidence'... Even more evidence has come in since, to show longer is better when it comes to dosing. >My Girlfriend has had her 1st jab last week, she has been told she can come back as early as 3 weeks but they recommend to her to wait until 6 weeks then come back. No idea. Some of my friends are asking to get their second jab early to go on holiday, and getting told no chance of a second dose before 8 weeks. Is it possible you've just got the number wrong? Misheard it?


100% she didn't. She questioned why is it not 12 weeks. They said no more need to wait that long.


They reduced most peoples down to 8 recently, to get more people double jabbed before opening up. I got mine with an 8 interval. Not heard of anyone getting 6 🤷‍♂️


It's not just based on the one study though, it's also something we've seen over the years in other vaccines.


If you can source this I'll believe it!


https://www.sciencedirect.com/science/article/pii/0264410X89900467 There's one article showing higher antibody titres in those who received their second dose of Hep b vaccine late. https://www.sciencedirect.com/science/article/pii/S0264410X18312581 There's an article that shows when the time between first and second dose of HPV vaccines is longer the results are as good as with a third dose.


Nice, thanks! In this case i still think it'd be a good idea to have the second vaccine about 4 to 6 weeks after the first and have a third one a couple months after that, because otherwise everyone's gonna catch it just after one dose and be basically unprotected right?


There always will be small sample sizes. Inevitably the researchers will pick a window and test around that. Testing more and more scenario quickly becomes expensive


Sure, but this study was done ages ago, I'd have thought they'd be following up to check the claim on a broader age group to see if it holds up since its being used to advise govt policy.


It should be set at 8 weeks now. I had a jab at the start of June and have had texts/emails to say I can re-book the second appointment last week in July, which I have done. There's also way more appointments now so I was able to easily book in my preferred injection site. I'd advise your acquaintances to cancel and rebook, or call the vaccine hotline to speak to a real person to see if they can help move the appointment forward to the 8 week minimum.


I got mine 4 weeks after the first one last weekend by just walking into a pharmacy doing a walk-in clinic and asking.


There's concerns about long term protection in jabs given under 8 weeks so I don't blame them for holding out for the 8 weeks. At this point the elderly and vulnerable have long been double jabbed and it's those least at risk still waiting for second jabs so in terms of hospitalisations and deaths it shouldn't have a big impact. [But government scientific advisor Professor Anthony Harnden says for others, the "sweet spot" is eight weeks and any earlier means you won't be protected for as long.](https://www.bbc.co.uk/news/newsbeat-57682233)




Yeah ~90% protection is a fair few people having a bad time if you're rolling the dice 50k plus times a day.






The online system will let you move it to 8 weeks after your first jab, if that helps. I just did it, it was previously 12 weeks later.




>only book, view, or cancel appointments. Yeah you'll probably need to cancel it and rebook.




At least all the pensioners will be able to go clubbing soon


I mean I would but like …. I can’t get my second jab, opened up the country and people aren’t even fully vaccinated but fuck me right!?


Literally yesterday I have seen BBC saying that Pfizer is more effective against "delta", by about 5%. Everyone lie so much they confuse themselves


Wish I had been able to get my second pfizer vaccine before catching covid a few days ago. I think the one jab has helped to stave off serious illness (I had a couple of flu-ish days now it’s mostly just lung pain and breathing difficulties), but I am lucky in that I am young and relatively healthy. I fear what it would be like for my single-vaccinated friends with asthma etc.


Caught OG Covid in March 2020 and even though I physically couldn't sit up, had no respiratory symptoms despite lifelong chronic asthma. Thought it was very strange.


How bizarre. And I'm here experiencing respiratory problems for the first time in my life! It's a strange old virus isn't it. Glad you pulled through though in any case it's insane some can still trivialise this as a simple cold.


Its weird how i dont carry the healthiest of life and only had really high fever, i even had pneumonia in the past but i didnt have any of that with it, keep your room ventilated and clean, i dont know if its cold where you live but vapors and sweat help a loot with boogers and asthma things, i hope you get better and the second shot soon!


I'll borrow my parents humidifier, that's a smart idea. Thank you!


Some still think it's flu.


It's an immune system virus really, not respiratory. It just often causes lung issues.


What do you mean by immune system virus? Isn't any viral infection an immune system virus if your immune system reacts to it? (Which it does)


I got a hypothesis that people with asthma are under reporting the respiratory issues. Or non asthma people might be over reporting it . Everyone with asthma has had that shortness of breath feeling and are unfazed by it. They been there done that. Other people who have never had it are freaked the fuck out because it feels like they are dying and they never had it be before. Obviously this is only minor breathing problems


This is literally why focussing on get more people to the 1st dose rather than full vaccine cycle was crappy strategy to stick with as soon as Delta variant start spreading in Europe. Also, eliminated restrictions was simply dumb as fuck move.


I am in the same boat. 1st Pfizer shit 4/5 weeks ago, caught COVID this weekend just gone. Feeling fluey and heady, although breathing been fine so far.


Madness to think some are still content unvaccinated. I know many people now who are varying degrees of ill after one Pfizer jab. Given that studies appear to show that a single dose is only 11% effective or so at stopping Delta, we're in for a long month of infections among young people.


My housemate refuses to get it because she thinks it might give her Creuztfelt Jakob Disease so... [shrugs]


Sounds like she already has it


my sister had two for months now and she just tested positive the day she arrived on holiday.


It's weird seeing a more upbeat attitude towards Covid and vaccines on this subreddit. What's happened?


These threads never seem to have as many posts in them as the others. I think that with the scientific data right there, there's less room for the rampant speculation and armchair epidemiology that we see in other threads, and concurrently less scope for generic government-bashing which takes up a huge proportion of those other threads.


Because the issue is not with the current varients and the current efficacy against those variants, which we see in the numbers as being quite good given FULL efficacy. The concern with opening up when there are rising case numbers is quite simple and is around vaccine escape. I'm lazy so am reusing a summary of why we're basically walking into the perfect storm for a vaccine escape variant to emerge. Currently we can think of having 3 groups of people.in the country. Those with no vaccination, those with full efficacy from vaccination, and those who've been vaccinated but are yet to develop full immunity. The issue is mainly with this last group. These people make quite a large number of the population, approx 200-300k being first dosed each day, and with a 10 weeks between jab 1 and finally developing full efficacy, it can be very roughly estimated that there's 17.5 million people who have a reduced efficacy (but of course there's a nonlinear ramp up to full efficacy so some are worse than others and this is a very rough ballpark figure). Further, because rollout has been age stratified too it means that there's a higher probability of cross infection between those in that 10 week window because of the nature of social networks. When someone gets infected, the virus replicates until the immune system deals with it, and each one of those replications has a probability of of an replication error, and each replication error has a probability of being capable of vaccine escape and thats true in anyone. In an unvaccinated individual, those mutations capable of vaccine escape will likely be overwhelmed by other lineages, and in a person with full efficacy, the immune system will hopefully kick in quite early and cut down the number of replications. However, in the recently vaccinated person, the body will take quite a while longer to get up to speed and deal with the infection, giving the virus more time to replicate, generating orders of magnitude more copies of itself than in the individual with full efficacy. Unlike in the unvaccinated person, the immune response will have learned from the antigens in the vaccine, and the antibodies produced will target in the way they do in a fully vaccinated individual. Therefore, lineages which are capable of vaccine escape will be more likely to thrive relative to other lines because they have an evolutionary advantage when up against these antibodies, and with so many more replication errors, the chances of one of these strains becoming dominant and infecting someone else is greatly increased. This is why having a situation where there is a high incidence (check) and a large population who have a low efficacy (check) is a perfect storm for vaccine escape, and if you want to worry, that's a pretty reasonable thing to be concerned about.


Has a similar study been done to see if Monderna (my second jab of this next week) has a similar effect?


The pamphlet I received when I had my 2nd dose of Moderna on Monday stated that it has a 70% efficiency on the Delta variant after the 2nd shot.


Huh, that seems lower than what I'd been hearing.


In Canada we consider Pfizer and moderna to be the same vaccine. (The only difference is health Canada approve for 12-18 year old) They are very very similar vaccines. I believe Pfizer is paying a license to moderns or biontech for parts of the vaccine too.


Moderna is just as good if not better than Pfizer because it has 100micrograms of the mRNA while Pfizer is 30micrograms


Is there any data about how effective it is against transmission? Like can vaccinated people pass it on to unvaccinated?


They can, but remember that if the vaccine prevents the majority of symptoms, this will massively decrease transmission by itself. Without people openly coughing around you, the chance of catching the virus is significantly lessened. This would be the case even if the immune response triggered by the vaccines didn't also decrease viral load, which further decreases transmission.


Thank you. This is important information that I hadn’t considered. Still pretty anxious about it, but this is reassuring.


What I've heard is that two jabs reduces the probability of transmission by over 50%. Which means that, sadly, covid is not going anywhere. We don't have a vaccine that reduces the effective reproduction value below one, that can only be achieved with strict mitigation measures like complete lockdown. Whenever we open up, there will be an increase in cases. This is the reasoning behind opening up now, during the summer. If we open up in autumn then the wave will coincide with flu.


The thing is that you can also be reinfected so it’s possible herd immunity isn’t possible either and the only strategy is management and hoping it gets less severe soon


I have been wondering (though not sure if there’s data?) about the effect of the vaccination on the results of lateral flow tests missing positive cases. I remember hearing a lot about LFTs missing a large number of cases when people were less infectious. Potentially that’s now the majority of cases?


Yeah that was my worry. I’ve got my second jab this week but have a son who is too young. Scared that I’ll just pass it on to him :(


If it helps, vast majority of kids have either no or extremely mild symptoms.


What is the effective reproduction value (among unvaccinated population) of covid, and what reduction in transmission is needed for 90% vaccination to push it below 1?


> 90% vaccination Just as a reminder though: we're currently inching closer to 90% of the *adult* population being vaccinated. Overall, it's a lot less.


Short answer is yes. Vaccines reduce transmission but don't prevent it. A vaccinated person can still spread it, and may have no symptoms.


Two shots of whisky, gin effective enough for Eric Clapton fans.


I'm currently 2 weeks past my second AZ jab. I'm still resigned to catching it somehow


even though its 67% its still not great for those of us that had AstraZenica, its better than nothing but still a downer ;(


This was not surprising, but still, people need to remember that full immunity takes about 2 weeks after the second dose to kick in. I see people getting their shot and ripping that mask right off.


RIP me suffering through fever of 39.6 with the Moderna second dose then? EDIT: Not to put anyone off, I think the reaction I had is a less common one.


Just because Pfizer and AstraZeneca *are* effective doesn't mean Moderna *isn't*.


According to [this](https://www.healthline.com/health-news/heres-how-well-covid-19-vaccines-work-against-the-delta-variant#Vaccines-vs.-delta-variant): > **Estimated effectiveness of Moderna COVID-19 vaccine** >One study estimates 72 percent effectiveness from one dose. Other studies suggest it may offer similar protection as the Pfizer-BioNTech vaccine.


if I get the Pfizer one next I get 155% protection total right?


You joke but I have seriously wondered if this is a viable option. I have next to zero understanding of how these vaccines work but I've heard they use slightly different methods to cause antibodies to form, so theoretically taking 2 jabs of AZ after my pfizer jabs should improve my antibody count... right? ^^^^and ^^^^my ^^^^5g ^^^^connection ^^^^rate? Would love someone who actually knows this stuff to chime in!


They're actively studying the impact of adding a 3rd booster - e.g. Pfizer if you had Astra, and vice versa. I saw news articles about UK/Cambridge clinical trials back in June. A Spanish study released in May showed that mix & match produces a "potent immune response". But you only need 1 follow up jab, not 2. Very roughly, there are about 82.8 million doses already given in the UK, and 22.5 left to give for adults. At 300k doses a day that's 75 days of adult jabs left. So boosters in October? Maybe earlier if the people lining up for their first jab drops dramatically. It might just be for vulnerable folks at first though. From the UK gov data, there are 6 million adults left who haven't had a first dose yet (11.9% of adults). Note: timing about boosters is just my speculation, and back of envelope maths.


I think their plan is to offer a Covid-19 booster and the flu jab to those over 50 years old come the Autumn. I don't know when they usually start the flu jab rollout but I assume it'll be a similar time for the one two punch of flu jab and Covid-19 booster. Might come down to what supplies are available though!


Sign up here if you want that: https://www.c19vaccinestudy.com/#!/


Seconding this, I really want the pfizer ones too on top of the AZ ones I've already had, preferably within the next few weeks. It does work, you get a MASSIVE boost in immunity by having both brands. Problem is, I've devised a couple of very simple ways of doing this illegally and unethically, but can't find any options whatsoever to do it legitimately. I'd pay lots for it too, and know they must be binning thousands of doses a day. Could be a good money earner for the NHS if they put short date / excess doses up for sale / bids for paranoiacs like myself.


In Germany everybody who got vaccinated with AZ gets an mRNA vaccine as the second jab. AZ will be phased out completely.


Note that this case "effectiveness" is with regards to symptoms. AZ is only 60% effective against infection, Pfizer about 85% effective against infection by the delta variant.


67% doesn't fill me with confidence when so many people have it. Maybe if you have the Pzifer you can run around licking as many handrails as you like but 1/3 chance of getting sick doesn't sound great for AZ?


it's not 1/3 chance because getting sick from the rona wasn't a certainty to begin with, if you think of your chances to get sick as Y% then your chances to get sick once vaccinated are (Y x 1/3)%* *edited because i a big stupid


> (Y x 2/3)% Did you mean to write (Y x 1/3)% [?]


fuck. Yes I did or Y/3% probably works better


It’s better than nothing, as long as they’re vaccinated it still slows down the spread


Quite a few of my Pfizer vaccinated friends recently had Delta with symptoms...


Having the vaccine doesn't make you immune. Just less likely to end up in hospital.




It's bizarre how similar our experiences are right down to the dream. I hit ten days tomorrow and no smell, feel nearly 100% after pretty much the same path as you. The dreams I'm having a wild




Well the beta variant is more vaccine resistant which is why France is on an amber+ list if that floats your boat.


I always LOL when I see a Grant Shapps announcements proclaiming which countries we have place on green are whatever and we are the plague island. Bulgaria banned us about an hour after we put them on our green list.


Yeah, I think we have more beta variant cases than France.


No we don't lmao The UK sequenced 70k cases in the past 4 weeks and found 4 beta cases. France sequenced 2000 and found about 200. 0.006% versus nearly 10%.




Having just had my second Pfizer yesterday, excellent news. Shame I feel like shit currently though.


hoping two sticks of moderna will be around 88-95% as well


Hm, i got 1 AZ and 1 Moderna, thats not researched i guess?


If I had received AZ at the time I wouldn't have minded, but as a 30 year old who got his second jab last Saturday, I'm more glad as time goes by that I got Pfizer. Out of all the main vaccines in the UK and America, going by all the data it feels like Pfizer and Moderna are the best ones at the moment. AZ seems fairly hit or miss by different reports.


Why are people downvoting this? Dampens their apocalyptic hysteria?


What are you even talking about? It's at 92% upvoted. It's getting real tiring hearing people complaining about 'hysteria' as they sit in the country with the third-highest case rate in the world and only marginally better vaccine coverage than, say, Ireland or Belgium. Caution is warranted here, wanton desire to throw away logical measures such as masks at the same time as we open up close-contact venues is just stupid.


> only marginally better vaccine coverage than, say, Ireland or Belgium We're quite a bit bigger population wise than both those countries, so still a pretty big achievement


Oh, it is definitely a big achievement, I am simply pointing out that acting (1) as if people are against this news and (2) as if we're out of the woods are both stupid positions. The whole thing smacks of the old 'project fear' moniker, which in reality was always just people who were looking to experts and data to guide them, rather than blind nationalism and impatience with beurocracy.


There's a crowd of tinfoil hatters and antivaxxers who camp on /new and downvote things they don't like, like vaccine news and anything to do with reducing the spread of covid.




You'd think we had enough homegrown stupid


We definitely do, but when it comes to this sort of thing it's actually much smaller than most other countries. As a whole, people in the UK are much more in favour of getting vaccinated for example. Unfortunately, the internet allows the loud, conspiracy theories minority to feed off those groups in other countries, and also spread it in the UK too via social media.


Yup, comparing the UK to Romania for instance: 25% have been vaccinated so far in Romania, and it seems that's all the people who *want* the vaccine. The rest are afraid of side effects, or genuinely believe that it has Bill Gates microchips or that they'll develop scales if they get it. My cousin's husband made a post on Facebook saying it's "curious how the same people who want population controls have also released this vaccine". And apparently there's a rumour in Hungarian minority villages that it turns you into a Romanian (I'm serious)...


I will just say that from feb-jun there were only 117 deaths from the Delta variant. Only 8 of those were under 50 years old, or 0.0% [https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment\_data/file/1001354/Variants\_of\_Concern\_VOC\_Technical\_Briefing\_17.pdf](https://www.reddit.com/r/unitedkingdom/comments/op8owf/two_doses_of_pfizer_astrazeneca_shots_effective/) UK Gov numbers, page 10 All this push, all these restrictions for 25 deaths/m from the 'deadly' delta variant.


https://www.nejm.org/doi/full/10.1056/NEJMoa2108891 > the effectiveness of two doses was 74.5% (95% CI, 68.4 to 79.4) among persons with the alpha variant and 67.0% (95% CI, 61.3 to 71.8) among those with the delta variant. So a 1-in-3 chance of getting it despite being vaccinated, instead of 1-in-4. That's still pretty significant when you're talking about millions of people.


It’s a bit more complex than that. Some other comments explain a bit more in depth.


Does it matter how far apart the doses are, different butt cheeks, which days of the week etc?


You’re supposed to have one in each cheek, otherwise it looks uneven in your Instagram pics


TL;DR: Against the Delta variant Pfizer is 88% effective and AZ is 67.0% effective. Assuming the estimation that we need 70% immunity for herd immunity is accurate that means, unfortunately, the AZ vaccine alone can't possibly be good enough to create herd immunity. With Pfizer too this means that 80%-100% of the country to be vaccinated to create herd immunity. Hopefully natural immunity can take care of the rest.


Delta no longer something to be scared of… the news will be reporting on a new even more spooky scary variant any day now….


9 out of 10 people who died with/of Covid in uk were over the age of 80, 6 out of 10 were also disabled Let that sink in sheeple, so please stop shitting your panties, take off those ridiculous masks and get on with your lives


Oh ok then it's alright if I'll only be killing a lot of old and disabled people, their lives of course do not matter.


Why can't they just go get their vaccine if they are susceptible?


Exactly, if you choose not to have the vaccination then if you get ill then tough shit


The point is that you don't heavily disrupt the lives of young people to give people who are already beyond the average life expectancy, and are already vaccinated, a few more months. We never did that before, for more deadly viruses.


Finally, an actual fucking study instead of just *you should take this because we say so*. I'm no anti-vaxxer but the actual data we've been provided concerning the vaccines has been fucking atrocious. Sensible critical voices have been silenced in favour of 1984-style thought policing and yet many are still surprised that ablarge amount of people are fearful of these **new**, pseduo-mandatory vaccinations. Of course I will be getting jabbed but I would at least like to know for certain what the benefit is.


Agreed. I am in the same boat. Some information on how long the antibodies decay would be very nice too.


>Finally, an actual fucking study instead of just > >you should take this because we say so > >. There have been lots of these sorts of studies, to be fair. They're just constantly doing more, as we get more data from more people getting jabbed, different age groups getting jabbed, and the delta variant becoming more prevalent. But the numbers are fairly similar to previous studies.


>Finally, an actual fucking study instead of just you should take this because we say so. unfortunately it's not a very high quality study and we still don't have proper studies on how long the protection from these vaccines lasts