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Medicine

Pfizer Vaccine Effectiveness Drops To 84 Percent After Six Months, Study Finds (thehill.com) 301

An anonymous reader quotes a report from The Hill: The effectiveness of the Pfizer-BioNTech COVID-19 vaccine fell from 96 percent to 84 percent over six months, according to data released on Wednesday. The preprint study funded by the companies determined that the vaccine's effectiveness reached a high point of 96.2 percent within two months after the second dose. But the efficacy "declined gradually" to 83.7 percent within six months, with an average decrease of about 6 percent every two months. But even with the slip in efficacy, the data indicates the vaccine offers protection six months later.

The ongoing study with more than 44,000 participants across the Americas and Europe determined the vaccine was overall 91.1 percent effective, after 81 cases emerged among the vaccinated and 873 among those who received the placebo. The efficacy of the vaccine against severe disease including hospitalizations remained high, at 97 percent. Researchers will continue to observe participants of the study up to two years and combined with "real-world" data "will determine whether a booster is likely to be beneficial after a longer interval." If the efficacy continued to decrease at the current rate, it could fall below 50 percent within 18 months, suggesting that booster shots could be needed.

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Pfizer Vaccine Effectiveness Drops To 84 Percent After Six Months, Study Finds

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  • Stupid people (Score:5, Insightful)

    by cygnusvis ( 6168614 ) on Thursday July 29, 2021 @08:04AM (#61633643)
    Some people still think after 2 billion test subjects and already having all the other vaccines, the Covid vaccine is somehow dangerous
    • by Opportunist ( 166417 ) on Thursday July 29, 2021 @08:10AM (#61633667)

      It is! Mostly it's dangerous to my beloved home office.

      If the infection numbers go down too much, they force me to come back to the office.

      • Just stop bathing. That will solve that problem.

    • by HiThere ( 15173 )

      Just about everything is dangerous. The question is how to balance the dangers, and some people are really bad at doing that balancing.

      Others, of course, have the conclusion ahead of time, and engage in "motivated reasoning".

      • One thing I've been wondering...

        If you are vaccinated and like most vaccinated you've been out in the world, maskless and back mostly to regular life....surely we all have been having micro-exposures to the covid virus out in the real world.

        If so, wouldn't that basically keep your immune system at alert and keep your immune system ready with anti-bodies, etc?

        I was just wondering that with the vaccine, you have been protected with that, but also since it made you comfortable with going out in the world wh

        • by znrt ( 2424692 )

          my thoughts: it all depends on numbers: exposure vs resistance. your immune system may recognize the threat, but it still has to actually fight back strongly enough to overcome the spread, which pits the viral load against the efficiency of your particular immune system. some (the asymptomatics) can do that naturally. for the rest the vaccine is a huge head start, but every infection is still a fight that has to be resolved.

    • Re:Stupid people (Score:4, Insightful)

      by MooseTick ( 895855 ) on Thursday July 29, 2021 @08:59AM (#61633917) Homepage

      I find it amazing how people refuse to take the vaccine due to conspiracy theories that the government has tainted it somehow, yet they have zero hesitation to consume anything offered up by McDonalds, Starbucks, Subway, Coke, M&Ms, or their local grocery store. If the government were so sneaky and all powerful, wouldn't you think they could put those "nanochips" in our coffee, hamburgers, sodas, or ramen noodles years ago?

      Now you may say those are private companies, but couldn't the government have created a shell corporation and bought a major food supplier? Or had NSA/FBI/SHIELD infiltrate one or more company to "get us"?

      I know all that sounds crazy, but if you believe there is a conspiracy to fake a pandemic to "trick" the world to take a shot; then all the above should be reasonably logical.

  • by dmay34 ( 6770232 ) on Thursday July 29, 2021 @08:05AM (#61633645)

    The goal was never to eradicate Covid. That would be awesome, and I would be all for that if it was possible, but it's simply not possible. Even if we could get every human on earth fully vaccinated this week, the virus is spread between species. We can't vaccinate all the bats. (And, again, that is predicated on the impossible task of vaccinating every human.)

    Covid is a fact of life now, and will be for a very long time. Probably the rest of our lives. Regular boosters will probably be necessary every year. That's just the way it's going to be.

    • by dmay34 ( 6770232 ) on Thursday July 29, 2021 @08:08AM (#61633657)

      The goal now is to convince everyone possible to get vaccinated and get their boosters so that we stop overwhelming our healthcare infrastructure systems with Covid infection waves.

    • Maybe not possible due to humanity's increasing susceptibility to misinformation. Certainly not due to limited effectiveness of the vaccines.

      • by dmay34 ( 6770232 )

        Even if the misinformation wasn't an issue, it's a very difficult race to win. It will be very hard to vaccinate the whole world faster than the virus can naturally mutate and decrease a vaccine's effectiveness.

        And even if we could do that -which would be an unparalleled feat of logistics all in human history- the virus will still continue to exist and evolve in animals and find its way back into the human population.

        • two advantages (Score:5, Informative)

          by DrYak ( 748999 ) on Thursday July 29, 2021 @09:41AM (#61634155) Homepage

          It will be very hard to vaccinate the whole world faster than the virus can naturally mutate and decrease a vaccine's effectiveness.

          We have two mechanism playing at an advantage for us:

          - Coronaviruses have a slower mutation rate (they have an exonuclease function on nsp14 - giving them "proof-reading" capability) compared to your average RNA virus.

          - Vaccine specifically target the Spike, the protein that the virus needs to enter the host cell. The vaccine can't mutate than one too much or it loses its ability to infect humans. The virus is in a "key-and-lock" matching dead-end.

          - Unlike Influenza virus which has a segmented genome and thus can very easily shuffle around segements if two different virus infect the same host (E.g.: a swine infected by both an avian and human strain), coronavirus lack some similar mechanism to drastically increase recombinations, and thus cannot as easily bring a sudden entirely new Spike in the game.

          This might helps us outpace virus mutations with our vaccine campaign.

          And even if we could do that -which would be an unparalleled feat of logistics all in human history-

          Not true, there are even slower mutating viruses (mostly DNA-based ones) that we have nearly eradicated using even older (and slower) vaccine production technologies.
          We have outpaced viruses with vaccines in the past.

          the virus will still continue to exist and evolve in animals and find its way back into the human population.

          Well, that I agree:
          given the first SARS and then MERS one and two decades ago, chances are, by 2028, there will could be some SARS-CoV-3 emerging causing yet another new disease.
          (Those will simply be considered a different virus).

      • by timeOday ( 582209 ) on Thursday July 29, 2021 @08:21AM (#61633709)
        Deaths could be reduced to effectively zero with nearly full vaccination through herd immunity, and I expect many (other) nations will accomplish that. But he has a point, it would still be floating around in bats and other animals.

        Eradication is a super-high bar. Earlier this month a 10 year-old girl in Colorado died of the plague! First fatal case in the US since 2015. So, we can't say the plague is eradicated, even though the risk is nearly eliminated.

        • How long before someone suggests that we exterminate all the wildlife? /s
        • by quenda ( 644621 ) on Thursday July 29, 2021 @09:03AM (#61633927)

          But he has a point, it would still be floating around in bats and other animals.

          Not true. Covid-19 occasionally infects other mammals such as pets, but is not "floating around in bats".
          Bat populations carry countless coronaviruses, but Covid-19 is not one of them. Its ancestor probably came from bats. This is a specific virus that is spreading only in humans.
          So unlike plague bacteria, eradication of covid-19 is theoretically possible.
          But then, the same applies to measles. We could, but haven't. So far we have only eradicated smallpox.

          • by AuMatar ( 183847 )

            Cats however do have the virus. Including tigers in the Central Park Zoo that tested positive. So we can't really eliminate the virus. We can reduce it to the point its not a major concern, like we have with other past plagues (the Black Death still kills people every year, but its contained).

            • by quenda ( 644621 )

              Including tigers in the Central Park Zoo that tested positive. So we can't really eliminate the virus.

              A huge assumption there, based on a tiny amount of understanding.
              The tigers are not infecting people, and not other tigers. It is a dead-end for the virus.

              I suppose it is conceivable that a strain of covid-19 might become endemic in another species, but that has not happened.
              Zoonotic viruses infect people all the time. But very rarely does the virus spread and stay in the human population long enough to be noticed.

          • Bat populations carry countless coronaviruses, but Covid-19 is not one of them.

            Covid-19 is a disease caused by a virus. The virus SARS-COV-2 absolutely could be in bats. Have you looked? We've found the virus in a myriad of animals when we've gone looking for them. Hell Denmark was at one point talking about culling 17million mink just to stop an animal based spread. It definitely is not only spreading in humans.

            • by quenda ( 644621 )

              The virus SARS-COV-2 absolutely could be in bats. Have you looked?

              A lot of virologists have been looking. Sars-cov-2 is believed to have come from a bat virus, but no, has not been found in bats.

              Hell Denmark was at one point talking about culling 17million mink

              They did. I'f forgotten. But I don't believe it ever spread to a wild population.

              It definitely is not only spreading in humans.

              Definitely? Then tell me where? The mink are dead. Without humans, sars-cov2 would very soon be extinct.
              Viruses can cross between species - thats where new human viruses mostly come from.
              But that does not mean the other species is a reservoir, like rats for plague bacteria.

    • But we're working on eradicating the wildlife population on another front, it just takes time.

    • by HiThere ( 15173 ) <charleshixsn.earthlink@net> on Thursday July 29, 2021 @08:26AM (#61633731)

      That's not true. Early on many people's goal was to eliminate COVID. That's been known to be improbable for a long time.

      FWIW, just because there's an animal reservoir doesn't mean you can't eliminate the human disease. Often the human variant depends on having acquired mutations that allows it to spread between humans, and those mutations aren't successful in the animal reservoir. Also, relatively few people are exposed to bats or pangolins, or whatever the reservoir is, so if just those few are protected, then the disease won't exist among humans.

      • "Early on many people's goal was to eliminate COVID."

        It wasn't ever the goal of anyone who had any understanding of the issue. It is patently impossible to eliminate a virus that can infect wild animal populations. (Smallpox only infects humans--that's why we were able to wipe it out).

      • One of my favorite xkcd cartoons was the daydream about eradication. Especially the mouseover text.

        There is a controversial idea for addressing animal reservoirs. Injecting vaccine into every bat is laughable, but what about taking a viral vector vaccine and skipping the step of putting it through the genetic engineering spay/neuter clinic, and leave it able to spread? Then almost every exposed bat gets COVID-19 immunity.

        As one of my colleagues said at a seminar once where someone presented something shiny,

    • Smallpox (Score:5, Informative)

      by JBMcB ( 73720 ) on Thursday July 29, 2021 @08:26AM (#61633737)

      Smallpox was the deadliest (in terms of deaths) virus of all time. It was more virulent than COVID, and did more permanent damage and was more lethal (1-30% depending on the strain) It's been completely eradicated. The last outbreak was in 1978, probably caused by someone being exposed in a lab.

      So what makes you think we can't do the same thing for COVID?

      • Re:Smallpox (Score:5, Informative)

        by jbengt ( 874751 ) on Thursday July 29, 2021 @08:55AM (#61633879)

        It's [smallpox] been completely eradicated. . .

        So what makes you think we can't do the same thing for COVID?

        Smallpox had no animal reservoir. SARS-CoV-2 does.

        • by hey! ( 33014 )

          A lot depends on the interactions of human populations with animal reservoirs. For example West Nile Virus is vectored between the enzootic reservoir (birds) and humans by mosquitoes. Influenza infects farm animals, and therefore any humans that handle them.

          The natural focus of SARS-COV-2 is the horseshoe bat, which doesn't have a close relationship to human populations. There is evidence that viruses from bat roosts spill over into neighboring wildlife and livestock, but that should be mitigateable with

          • SARS-COV-2 *can* infect other mammalian species, so it is conceivable that it may find some kind of enzootic reservoir

            Did you miss the story about Denmark proposing to cull 17million mink because of wide and rapid spread of this very virus throughout the country's population? Or the WHO announcements that you absolutely should limit interaction with animals if you're diagnosed as we've already identified SARS-COV-2 spreading among cats, dogs, and even zoo animals?

            • Re:Smallpox (Score:4, Insightful)

              by hey! ( 33014 ) on Thursday July 29, 2021 @10:55AM (#61634501) Homepage Journal

              No I did not. As I said SARS-COV-2 can infect other mammalian species, but the ecology of a persistent zoonosis is not nearly as simple as you imagine. For example the reason China is often implicated in flu outbreaks is that it's common to raise both poultry and pigs on the same farm -- something that was true in the US when 1918 flu emerged. This makes it possible to link human populations with migratory birds, e.g., migratory birds to domestic ducks to pigs to people, or migratory birds to chickens to people.

      • Spanish Flue [youtu.be] took about three years and that's with much more advanced an understanding of illness and medicine. Smallpox predates [wikipedia.org] (BC) all of that. So our "doing the same thing" could have only happened much much latter with that understanding.

      • by hey! ( 33014 )

        Smallpox is the one time humanity has ever managed that, and it took twenty-five years. The barriers to accomplishing that faster weren't technological; they were political and still exist today.

        The smallpox vaccine confers lifelong immunity, but not every vaccine does this. We just don't know how long the immunity conferred by COVID-19 vaccines last. It's not out of the question that annual boosters will be required. Given that, and COVID-19's trick of spreading via presymptomatic carriers, it could be

        • Smallpox is the one time humanity has ever managed that, and it took twenty-five years.

          Technically true, but Polio is on the ropes, and Measles has been all but eliminated in many industrialized nations (thanks to the anti-vaxx crowd it's been doing an encore performance in several countries, including the United States). So I don't think it's unreasonable to work towards eradication, but yes, it is tough and requires a concerted effort.

      • We don't appreciate that enough. Dr. Henderson and his team should have statues.

        It's worth noticing that smallpox is the only human virus we've eradicated, though we're getting close with polio. Eradication is one of those possible-but-very-hard problems.

        One key difference is that smallpox didn't have a mass movement actively taking its side.

    • by smooth wombat ( 796938 ) on Thursday July 29, 2021 @08:37AM (#61633787) Journal
      That would be awesome, and I would be all for that if it was possible, but it's simply not possible.

      We got rid of smallpox and rinderpest. Yes, I realize they are different from covid, but it is possible to rid the planet of diseases if we try hard enough. Polio is effectively eliminated across the planet with only a few cases popping up in third world backwaters, but that's because of lack of vaccinations.
    • We have technology to rapidly develop vaccines. We're not even that far off from the general purpose vaccine. At the very least we could eradicate this particular strain in the developed world. All we need to do is get people to believe in science again.
    • by quenda ( 644621 )

      The goal was never to eradicate Covid. That would be awesome, and I would be all for that if it was possible, but it's simply not possible.

      We did eradicate it in Australia and NZ, but it keep arriving on planes and boats.
      My state (W.Aus.) has had only one outbreak this year, with two people catching Covid from a lady who returned from Sydney infected. That's it. The rest have been in quarantine.

      Even if we could get every human on earth fully vaccinated this week, the virus is spread between species.

      That is very rare. Are there any known cases of animal to human transfer since the original jump?

      Regular boosters will probably be necessary every year. That's just the way it's going to be.

      Probably. They can just add it to our annual flu shots. By the way Pfizer's 84% after 6 months is good news! It is much better than the current flu vaccin

    • Well eradicating COVID is hard, but to get the numbers way down to below the Flu rate (as it is more deadly, also brings up more complications than the flu) is doable. But they are too many areas Like Mississippi, Arkansas, Alabama, Louisiana are surging up to rates much higher than larger more dense states, because they are not getting vaccinated, mostly due to electing morons for their local government who much rather spread misinformation, than to actually try to fix the problem.

      If they need to put a Rep

      • ...and at some point, those unvaccinated will either die, or attain natural immunity from having and surviving the disease.

        Even now in LA, we're seeing spikes sure...but nothing nearly as bad as last year, likely due to the numbers of vaccinated we do have combined with those with naturally attained immunity.

        • Let me cut off your arm now, so you wont have to worry about breaking that arm later.
          The longer we let this go out of control the more mutations will occur, and spread. Possibly leading to a mutation that the Vaccines will not be able to protect us.

    • The goal was never to eradicate Covid.

      Indeed, the primary goal was to keep the healthcare system from collapsing,
      and then as a secondary goal bring the risks of death and complication low enough that it becomes acceptable to restore normal work,
      bringing case number to zero was seen as a bonus point.

      That would be awesome, and I would be all for that if it was possible, but it's simply not possible.

      Not quite agree...

      Even if we could get every human on earth fully vaccinated this week, the virus is spread between species.

      If you could insta-vaccinate the whole population, you would be severely hampering the virus' ability to circulate.
      - on the "target host" side: vaccinate people have a much lower chance of getting infected when exposed.
      - on the "em

    • by tragedy ( 27079 )

      Vaccinating animal populations is not actually impossible. It's easier if you have an oral version of the vaccine to put in their food supply. The critical thing is that most animals are not anywhere near as mobile as human beings (true even for the migratory ones, since they tend to travel fairly fixed routes only at certain times of the year and many of them also form natural bubbles), so you can usually concentrate your efforts on populations where infection has been detected. It may be hard to completel

    • It's thought that the seasonal influenza that we became used to for most of our lives was a descendent of the virus responsible for the 1918 pandemic. COVID-related lockdowns pretty much shut down influenza entirely for last year's flu season, and the southern hemisphere flu season of 2021 doesn't seem to be happening either.

      While nobody knows for certain, it seems possible that COVID becomes the new flu (essentially replacing it as the dominate illness-causing communicable virus other than various cold-cau

    • Re: (Score:2, Insightful)

      by eepok ( 545733 )

      I keep hearing this... "The goal was never to eradicate COVID". Where was that ever said?

      I'll tell you what happened:

      1. "Flatten the curve" - Wear CLOTH masks and physically distance to reduce the burden on the healthcare system so it doesn't collapse while we...
      2. "Find a vaccine." - We're looking for a vaccine. Chill out. Stay away from people. Once it's available...
      3. "Get the vaccine" - Everyone who can get the vaccine without harming their health, should get it so we can reach...
      4. "Herd Immunity" - Wi

  • by DrMrLordX ( 559371 ) on Thursday July 29, 2021 @08:06AM (#61633651)

    Might be a reason why the breakthrough infections are happening; that being said, if you're vaccinated and getting routine, casual exposure to people shedding at least nominal amounts of Covid-19, wouldn't your immune system continue to develop more antibodies in response to repeated exposure as your body repeatedly fights off the disease?

    • wouldn't your immune system continue to develop more antibodies in response to repeated exposure as your body repeatedly fights off the disease?

      I would assume so, but at the same time I’d assume the general population (at least in areas where shots are available) wouldn’t be exposed to covid variants to the same degree they have been to the vaccine.
      It’s just a pre-print and I can’t find the actual paper but it seems like it’s not ruled out the vaccine keeps nearly constant effectiveness and it’s the variants that are causing the decline in overall efficacy. Immune response is more than just measuring antibodi

    • by hey! ( 33014 )

      Vaccines don't actually prevent you from getting infected; they help your body shut down before you notice. That's why vaccinated people can still spread COVID, although it's less likely.

      Just being in the room with someone who has COVID won't provoke an immune response. You need to get an infection large enough to trigger an immune reaction. That's a complex, multi-stage process that starts with the innate immune system generating an inflammatory response. This triggers the adaptive immune system to...

      • "Don't actually prevent" -- if you mean "Don't 100% prevent", completely true. The evidence is piling up that vaccines often prevent asymptomatic infection. That includes some big studies of health care workers.

        Even before the cytokine alarms go off, any SARS COV 2 that tries to form a beachhead in my body is going to be mobbed by already circulating antibodies, at the high levels created by an mRNA vaccine. It can't get into a cell with its spike protein glued to an antibody, and then the pair gets eaten b

    • I have no idea what casual exposure does to the immune system of a vaccinated person.

      It's important to note that breakthrough infections are pretty unusual. We don't know how unusual. In a widely criticized move the CDC decided not to track mild breakthrough cases. But we do know that out of 161 million vaccinated Americans, as of July 19 there had been only 4,072 hospitalizations. I wish I could always get odds like that.

  • Some guy needs to find the "break;" option for it
    • That would make Covid vaccination resemble the annual flu shots, which is not such a terrible outcome!

  • Do the J&J and Moderna vaccines also lose effectiveness as quickly over time? If not, can we use one of those other vaccines as a "booster" instead?

    Of course, Pfizer will not recommend doing that. They'll say that it's a safety issue, but for them it's also the loss of a recurring revenue stream. So, yeah... I'd want an independent study on that one that Pfizer isn't paying for.

    • They lose effectiveness due to the virus mutating so taking a different manufacturer's vaccine may provide little benefit. This is the same reason the flu vaccine changes every year as each one is against a different variant. The booster will most likely be based on a new strain.
  • Context is everything, boys and girls. Without corresponding herd immunity data, this only fuels the FUD.

  • Study Design... (Score:5, Interesting)

    by Thelasko ( 1196535 ) on Thursday July 29, 2021 @09:42AM (#61634159) Journal
    From what I've seen, it seems the study wasn't well designed to determine time as the cause of effectiveness drop. The drop in effectiveness could very well be caused by variants. The delta variant in particular. They merely compared whether the placebo group contracted Covid to the control group. Further testing to determine a breakdown by variant would have been much more insightful.
  • Or, if you believe Israeli data based on the actual real world, against the delta variant, it drops to about 38%.

  • Just an important note as to where this study came from.

  • That still beats the J&J vaccine by a lot.

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