How Does the Johnson & Johnson Vaccine Compare to Other Coronavirus Vaccines? 4 Questions Answered

Yves here. We are running this post for one reason: as this article stresses, the testing of the Pfizer and Moderna vaccines was conducted much earlier, when fewer variants were out and about. Therefore the Johnson & Johnson vaccine efficacy gives a much more realistic of what you could expect in terms of protection now.

So far, with Pfizer and Moderna, all we have are airy assurances and largely in vitro studies against the new variants. Both companies have discussed the notion of a third “booster: shot to contend with known new variants, which looks an awful lot like an admission that they suspect or even know the efficacy of their current offerings is meaningfully lower against some of the new variants.

Another way the efficacy data may not be comparable is in how they screened for Covid infections. Astra Zeneca tested all its clinical trial participants every week. By contrast, Pfizer used the dodgy approach of testing ONLY participants who developed “severe respiratory symptoms”. That means they ignored cases with loss of smell, the most reliable indicator of Covid, ones with digestive symptoms. and other symptom combinations that the CDC (and people I know) have found to be signals of Covid onset: fever, chills, headache, fatigute. And the “severe respiratory infection” only screen also means Pfizer did not catch mild or asymptomatic cases, even though we know they can do serious damage. From CBS News:

A Texas trauma surgeon says it’s rare that X-rays from any of her COVID-19 patients come back without dense scarring. Dr. Brittany Bankhead-Kendall tweeted, “Post-COVID lungs look worse than any type of terrible smoker’s lung we’ve ever seen. And they collapse. And they clot off. And the shortness of breath lingers on… & on… & on.”

“Everyone’s just so worried about the mortality thing and that’s terrible and it’s awful,” she told CBS Dallas-Fort Worth. “But man, for all the survivors and the people who have tested positive this is — it’s going to be a problem.”

Bankhead-Kendall, an assistant professor of surgery with Texas Tech University, in Lubbock, has treated thousands of patients since the pandemic began in March.

She says patients who’ve had COVID-19 symptoms show a severe chest X-ray every time, and those who were asymptomatic show a severe chest X-ray 70% to 80% of the time.

In other words, I’m sufficiently suspicious of the Pfizer efficacy numbers as to be willing to give Johnson & Johnson a go, particularly with its one-shot drill.

By Maureen Ferran, Associate Professor of Biology, Rochester Institute of Technology. Originally published at The Conversation

The U.S. Food and Drug Administration has authorized the use of the Johnson & Johnson coronavirus vaccine in adults. Maureen Ferran, a virologist at the Rochester Institute of Technology, explains how this third authorized vaccine works and explores the differences between it and the Moderna and Pfizer–BioNTech vaccines that are already in use.

1. How Does the Johnson & Johnson Vaccine Work?

The Johnson & Johnson vaccine is what’s called a viral vector vaccine.

To create this vaccine, the Johnson & Johnson team took a harmless adenovirus – the viral vector – and replaced a small piece of its genetic instructions with coronavirus genes for the SARS-CoV-2 spike protein.

After this modified adenovirus is injected into someone’s arm, it enters the person’s cells. The cells then read the genetic instructions needed to make the spike protein and the vaccinated cells make and present the spike protein on their own surface. The person’s immune system then notices these foreign proteins and makes antibodies against them that will protect the person if they are ever exposed to SARS-CoV-2 in the future.Our daily newsletter

The adenovirus vector vaccine is safe because the adenovirus can’t replicate in human cells or cause disease, and the SARS-CoV-2 spike protein can’t cause COVID–19 without the rest of the coronavirus.

This approach is not new. Johnson & Johnson used a similar method to make its Ebola vaccine, and the AstraZeneca-Oxford COVID-19 vaccine is also an adenovirus viral vector vaccine.

2. How Effective Is It?

The FDA’s analysis found that, in the U.S., the Johnson & Johnson COVID-19 vaccine was 72% effective at preventing all COVID-19 and 86% effective at preventing severe cases of the disease. While there is still a chance a vaccinated person could get sick, this suggests they would be much less likely to need hospitalization or to die from COVID-19.

A similar trial in South Africa, where a new, more contagious variant is dominant, produced similar results. Researchers found the Johnson & Johnson vaccine to be slightly less effective at preventing all illness there – 64% overall – but was still 82% effective at preventing severe disease. The FDA report also indicates that the vaccine protects against other variants from Britain and Brazil too.

3. How Is It Different from Other Vaccines?

The most basic difference is that the Johnson & Johnson vaccine is an adenovirus vector vaccine, while the Moderna and Pfizer vaccines are both mRNA vaccines. Messenger RNA vaccines use genetic instructions from the coronavirus to tell a person’s cells to make the spike protein, but these don’t use another virus as a vector. There are many practical differences, too.

Both of the mRNA-based vaccines require two shots. The Johnson & Johnson vaccine requires only a single dose. This is key when vaccines are in short supply.

The Johnson & Johnson vaccine can also be stored at much warmer temperatures than the mRNA vaccines. The mRNA vaccines must be shipped and stored at below–freezing or subzero temperatures and require a complicated cold chain to safely distribute them. The Johnson & Johnson vaccine can be stored for at least three months in a regular refrigerator, making it much easier to use and distribute.

As for efficacy, it is difficult to directly compare the Johnson & Johnson vaccine with the mRNA vaccines due to differences in how the clinical trials were designed. While the Moderna and Pfizer vaccines are reported to be approximately 95% effective at preventing illness from COVID–19, the trials were done over the summer and fall of 2020, before newer more contagious variants were circulating widely. The Moderna and Pfizer vaccines might not be as effective against the new variants, and Johnson & Johnson trials were done more recently and take into account the vaccine’s efficacy against these new variants.

4. Should I Choose One Vaccine Over Another?

Although the overall efficacy of the Moderna and Pfizer vaccines is higher than the Johnson & Johnson vaccine, you should not wait until you have your choice of vaccine – which is likely a long way off anyway. The Johnson & Johnson vaccine is nearly as good as the mRNA-based vaccines at preventing serious disease, and that’s what really matters.

The Johnson & Johnson vaccine and other viral-vector vaccines like the one from AstraZeneca are particularly important for the global vaccination effort. From a public health perspective, it’s important to have multiple COVID-19 vaccines, and the Johnson & Johnson vaccine is a very welcome addition to the vaccine arsenal. It doesn’t require a freezer, making it much easier to ship and store. It’s a one-shot vaccine, making logistics much easier compared with organizing two doses per person.

As many people as possible need to be vaccinated as quickly as possible to limit the development of new coronavirus variants. Johnson & Johnson is expected to ship out nearly four million doses as soon as the FDA grants emergency use authorization. Having a third authorized vaccine in the U.S. will be a big step towards meeting vaccination demand and stopping this pandemic.

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  1. vlade

    I have heard anecdotes about people have extremely severe reaction to the second shot of Pfizer’s vaccine, including extended (week+) hospital admission with permament lung damage (which, from vaccine, is weird IMO).

    This from a group of people who reported close to no, or trivial, first-dose reactions. Sample in tens, generally 30<age<55.

      1. Yves Smith Post author

        One MD who had to give a patient after an emergency tracheotomy after their reaction to the first shot had some difficulty with the FDA in getting them to record the incident.

        And see this from him as well:

        We have had yet another fairly significant vaccine reaction. I can make no sense of what happened to this young man.

        He is a “search and rescue” officer. In other words, he skis and hikes up to the mountains when people are hurt or killed. 27 years old – not an ounce of body fat on him. He runs six 5-minute-miles daily for fun. He received his first COVID Pfizer vaccine dose on JAN 11th. Within a day, he was having fever, chills, severe sore throat and a cough….. Very very sick for several days. He did have a full recovery. On his day for the 2nd dose this week on Monday, he went to the health department for the shot. He told them about the severe reaction and COVID positivity. The nurse and the county health physician advised him to get the 2nd shot. (This is in direct contravention to ANY vaccine training I have ever had. It has always been traditional medical care to wait an entire 4 weeks after ANY illness to give ANY vaccine. I am not at all sure what the urgency is to do this to people – but I have heard stories like this from all over). He received the 2nd shot. Within hours, he had to go home with severe fever and chills. His wife told me he was in such a stupor most of that evening that he was unresponsive at times. They had been told not to come to the hospital unless his pulse ox dropped, another mistake I am taking up with the health department. About 6 AM he began to have severe substernal chest pain – going into the jaws. His wife brought him into see me at 7 AM. His ECG done by me right then revealed profound ST elevation – TOMBSTONES as they are known – in the anterior leads. He was on the helicopter to XXXX within minutes – and there he was found to have completely normal coronary arteries. His cardiac troponin which I had drawn showed a massive elevation indicating an acute MI. This is a medical condition known as Printzmetal’s Angina – and is a sign of coronary artery spasm – or sudden endothelial damage – that immediately reverses itself. Fortunately, he is fine – doing well – and has no obvious long-term damage.

        I have zero doubt that this same mechanism is causing many of these “drop over dead” cardiac issues in NH patients who do not have the capacity of this young man.

        From a professor in a med school in a different part of the US, again on the Pfizer vaccine, everyone in his institution was so wiped out by the second Pfizer shot that they all had to take a day, and usually two, off work. That may not seem so bad unless you are not in a position to stay home.

        More generally, the problem here isn’t the possible financial consequences of a bad reaction via loss of employment income. It is that some people, far more than is normal for a vaccine, are having dangerous reactions, even if the aggregate percentages are small.

        1. vlade

          My current (entirely speculative layperson) theory is that the most severe reaction is caused by a massive overstimulation of the immune system of
          a) person with good immune system
          b) who contracted CV the first dose so that CV developed between the doses, even if the CV is otherwise mild to asymptomatic.

          From that perspective, if we assume that the second shot is even needed, I believe that a longer gap between the shots is likely beneficial as it makes it unlikely that the organism is requried to have three strong immune reactions in a short time.

          1. Yves Smith Post author

            You can’t get Covid from the vaccine. They only administer the spike protein. It is impossible to contract it that way.

            But it may be that a serious reaction could sufficiently weaken the recipient so as to increase their susceptibility short term….particularly given that the vaccines are often administered in places with lots of people…

            1. vlade

              Of course you can’t get CV from the vaccine.

              my text got scrambled a bit, what I meant to write was:
              b) who contracted CV after the first dose so that CV developed between the doses, even if the CV is otherwise mild to asymptomatic.

              The vaccine will almost certainly offer no protection in the first few days post application.

              1. rusti

                Yes, I had trouble understanding this important part of the story Yves relayed:

                He received his first COVID Pfizer vaccine dose on JAN 11th. Within a day, he was having fever, chills, severe sore throat and a cough….. Very very sick for several days. He did have a full recovery. On his day for the 2nd dose this week on Monday, he went to the health department for the shot. He told them about the severe reaction and COVID positivity.

                Does this mean he had a positive PCR test? When?

                1. Yves Smith Post author

                  I should have omitted that part entirely since the fact that he got Covid would add to the false notion that the vaccine causes Covid. Even the clinical trials listed the # of cases that happened after getting the vaccine, as do the follow on reports.

                  And I have no idea what kind of test he got, PCR v antigen.

            2. Cuibono

              that is what i wonder. Hearing enough anecdotal reports of this situation to think it merits attention.
              sadly asking this sort of question gets you labelled as anti-vax

        2. Dwight

          Is this MD’s case report from a personal communication? I’m very concerned about an elderly friend getting the vaccine a few months after having contracted and recovered from COVID, and would like to reference this case. You of course are an authoritative source for me, I just want to know where it came from.

          A Pennsylvania MD is convinced that vaccination after recent COVID infection is dangerous, and has written to FDA and Pfizer about this issue.

          This doctor recommends antibody testing before vaccination, which is a precaution I’ve always followed for me and my family so I consider it common sense. This doctor states in the below article that it is the standard of care but is being compromised by political pressure and “group think” about need for speedy vaccinations.

          This same doctor believes that a Memphis death was misdiagnosed as a delayed response to COVID, when in his opinion it was the result of COVID infection followed by vaccination.

          It’s very disturbing to hear that FDA may be discouraging adverse event reports even from physicians, as the reporting system is known to capture only a small percentage of events.

      2. QuicksliverMessenger

        Another anecdote here- both of my parents (78 and 80) had the second Pfizer last week and had no issues. Makes one wonder- some have zero reaction, others get into serious trouble, etc. Sounds a lot like the virus itself- some are asymptomatic with no issues, others find themselves with a grisly outcome.
        But I am definitely leaning to the J&J, especially with the one shot

        1. Irrational

          Parents-in-law (73 and 74) had no adverse effects from 1st or 2nd shot of Pfizer-Biontech.

        2. neo-realist

          A brother in law (69) and a mother in law (mid 80’s) reported no side effects after their second pfizer shot. I do suspect it is related to lower immunity in older age.

          Very encouraged by the pfizer Israel study-Health Ministry reported a reduction in infection in asymptomatic cases by 89% and symptomatic cases by 93%.

    1. voteforno6

      I know at least two people who’ve had a reaction after the second dose of the Pfizer vaccine, and one that had a reaction after the Moderna vaccine. The side effects for all of them went away after a day or so.

      1. vlade

        The severe reactions to the second dose in my sample weren’t things that would dissipate in 24 hours, they were more likely 3-4 days, and as I wrote, one extreme case of hospitalisation (male in his late 30s, fit) which may result in invalidity (CT scans seem to indicate substantial permanent lung damage).

        I’m not saying that this is expected, but I know that the people in the sample who had the first shot are now refusing the second based on the experience of their colleagues.

        1. grayslady

          Eighty-year old acquaintances were very sick for 3 days after second shot. Don’t know about lung scarring. He’s a retired doctor; she’s had heart issues in past. Ninety-year old friend had reaction 3 days after first shot–felt like he had the flu for a day–and he is just now noticing the lymph node swelling on one side beginning to subside as he’s due to receive second shot tomorrow.

        2. CoryP

          Not that I doubt your anecdote but I can’t imagine why there would be lung damage, even allowing for the idea that a vaccine can cause tissue damage. I mean, the ACE receptors are everywhere throughout the body and unlike a Covid infection the viral material isn’t being directly introduced to your respiratory tract and replicating there.

          Weird. This whole thing is very humbling in terms of how ignorant I’m feeling about concepts I thought I understood.

          1. vlade

            I don’t understand it either TBH, I’m just a messenger here. I’ve included it in the first comment that I consider it weird as I can’t see how a vaccine could have caused it.

            That said, by all accounts the guy was in a hospital, is still out of work, and his CT scans indicate lung damage.

            It’s possible it’s just a totally freak coincidence and that instead of reaction to the vaccine it was a real CV case that he wasn’t protected against and went full-strength on the day of vaccination.

            1. CoryP

              That’s my initial thought. That he actually got a full blown infection.

              If that’s not actually what happens my mind is blown.

              1. Dirk77

                Behind the curve here, but is it possible that the very common scarring lung damage that Yves mentioned may be less Covid and more about a haywire immune response to it?

    2. Jeotsu

      For what it’s worth…
      My Uncle (Age 79, pre-existing cardiac problem, not great health) got Covid back in ~December (by being foolish). Was hospitalised for about a week, then sent home (possibly earlier than he should have), and largely recovered.
      He received first dose of Pfizer the first week of Feb (so likely less than a month since full recovery, though I don’t have exact date). He had an immediate (first 24 hours) severe reaction, and was admitted to hospital and put on a ventilator. A week in he was looking at renal failure at least (news coming via family members who are not 100% on medical details). Shortly thereafter they sent him back for ~ 2 weeks of home hospice, and he died 8 days ago.
      So yeah, I have some serious questions about vaccine safety and administration. Like why someone who had just recovered was being jabbed?
      I don’t want to promote ‘vaccine hesitancy’, but I also feel like the most reasoned and balanced decisions are not being made. And the pursuit of profit is leading people to conflicts of interest when it comes to data recording and presentation.

        1. Yves Smith Post author

          The officials are recommending vaccinations even for people who have had Covid.

          There have been cases of reinfection with the same strain. The theory also is that vaccine-induced immunity would be stronger than immunity induced by the disease, although what I have read comes off more like pom-pom waving rather than evidence.

  2. bold'un

    For me there is also a question of the duration of the protection, and how quickly different jabs wane. If someone wants to be optimally protected next winter (21/22), it could make sense to have the J&J jab now followed by an early autumn jab possibly using a different viral vector (or a different technology) and ideally tweaked towards the predicted variants…
    There is a corresponding risk that someone who knows they are 95% protected with and mRNA jab in spring 2021, may wake up with Covid-22 one morning next January.

  3. Jason Elsome

    I’ve had both the BioNTech shots. The first was nothing, the second was very much like the shingles vaccination. I kind of ached all over for about 24 hours and then was done. YMMV

  4. Jen

    I’m thankful to be far down in the priority queue. Hopefully the J&J vaccine will be available here by the time I get to the head of the line. Moderna is what’s being given out up here. At this point, I know a couple dozen people who’ve had both shots. Some had no side effects. Some had minor aches, chills and weird things like their skin hurt. My cousin felt bad enough to stay home from work, and I’ve heard that from a few others as well. Most of the people I know who felt particularly bad after the 2nd shot were on the younger side, but my cousin is 62 so it’s not completely limited to the younger set. Overall, nothing overtly serious or lasting. All felt better in a day or two.

    I’m more curious about what happens over the long term, and glad of an alternative to the current vaccines.

    1. petal

      Jen, I have also observed that the side effects seem to be affecting younger people, say under 60s. The older folks(over 60s) I know haven’t really had any issues other than maybe a sore arm, but most of the younger people(most under 45) have become quite ill, feel like they’ve been hit by a truck for a few days, beginning about 12 hours post-vaccination. They’ve had to take time off from work. A whole group was out for 2-3 days after the second shot. For most of the group, their first shot went okay, 1 became very sick. The second shot laid all of them flat. Another friend elsewhere got very sick after their first shot(“worst they’ve felt in their life”). It’s been interesting.

      1. Jen

        Yep. Heard one of the patient care groups at the hospital learned the hard way that scheduling a lot of your staff to get the 2nd shot on the same day is not a good idea. Not the ED, thankfully.

        The PT practice I go to had one person who had to call out after the first group of them got the 2nd shot. The rest had some notable aches and pains but were able to work. My PT’s sister is a nurse, and she said the 2nd shot knocked her out flat. My 87 year old dad had is first shot about a week ago and reported feeling fluish for about a day.

        It certainly has been interesting.

  5. DoctorDoctor

    All of the FDA approved vaccines result in the body producing the viral spike protein. Moderna and Pfizer/BioNTech, through mRNA, J&J through DNA. The spike protein represents a fraction of the viral proteome, around 13% or so. And so the approach increases the odds of viral immune escape, as only a fraction of the proteome has to be mutated enough, versus enough of the whole viral proteome. Sinopharm and Sinovac use whole inactivated virus, OTOH.

    It may be that delivering the code for the spike protein into your cells is more efficient than injecting a whole inactivated virus, which must be digested, processed and presented. If so, than perhaps delivering the nucelic acid for the entire viral proteome would be the best approach. Stay tuned.

    And it is not the virus, per se, that always causes damage. It is the body’s immune response to it which includes cytokine storm. And so if the nucleic acid vaccines are more efficient at generating an immune response, then may be more likely to generate a harmful immune response. That is why some people have flu like symptoms after being immunized. It is the body’s response to the protein, cytokines.

      1. DoctorDoctor

        That is a non-sequitur. In fact the FDA has authorized the three vaccines. Approve is a synonym of authorize. They are, in fact, FDA approved vaccines.

        1. Yves Smith Post author

          That is absolutely false. You are apparently also Making Shit Up by presenting yourself as a doctor. Peddle your misinformation elsewhere.

          From UPenn’s medical school site:

          Vaccines for COVID-19 will start out being used under an Emergency Use Authorization (EUA) by the FDA. An EUA makes the vaccine available for public health emergencies. It means that the vaccine is available outside of a research study but is not yet approved.

          1. cocomaan

            I remind people that this is a EUA all the time, since people don’t seem to understand the importance of this state of exception in Pharma r&d (paging Dr. Carl Schmitt). It’s an end run around the normal regulations.

            I am incredibly wary about anything that skips the normal approval processes.

  6. CletracSteve

    This comment is basically highlights my confusion when reading about the two vaccine classes discussed in this post:

    Both of the mRNA and both of the adenovirus-vector vaccines rely on providing our cells with the recipe for synthesizing the spike protein. This is to be contrasted a vaccine that works through presenting an inactivated pathogen to the immune system.

    Why, then, do the adenovirus-vector vaccines demonstrate lower efficacy (assuming the different testing protocols discussed in the post don’t account for the entire difference). Would the JnJ and AZN vaccines show the same efficacy if they were two-dose regimens? Was a single-dose regimen chosen for ‘marketing’ purposes, making the overall distribution cheaper, simpler and more convenient? Or were the dose differences due to past practices with modified adenovirus vaccines while the mRNA approach is totally new and therefore treated to new thinking.

    Wife and I just received our second Moderna shot: minor headaches and sore arms.

    1. rusti

      Was a single-dose regimen chosen for ‘marketing’ purposes, making the overall distribution cheaper, simpler and more convenient?

      I think when they set up large scale clinical trials they just have to make a choice about this and then they won’t have statistically significant data about anything else afterwards. So J&J was taking a risk when they set up the protocol to have one dose but felt confident about their performance going into it. Sputnik V uses separate adenovirus vectors for shots 1 and 2, maybe to hedge against vector immunity?

      Also I’m sure there are a lot of caveats that I don’t know about, but J&J/AZ (unlike Pfizer and Moderna) pledged to sell the vaccines at “cost”.

    2. Yves Smith Post author

      Did you not read the damned post????? It’s a violation of our Site Policies not to.

      We pointed out AT THE TOP that the populations studied in the early Pfizer and Moderna trials were very different than the ones in the J&J trial, and the J&J trial clearly picked up far more variants. One test site was South Africa, which has produced a variant which does a very good job of escaping other vaccines.

      IIRC the efficacy of the J&J vaccine in the US was 82%. Not much off Pfizer, particularly given the issues with how they defined potential Covid cases to be tested (as in they omitted a shit ton of symptoms, so it looks likely that they failed to test people who had Covid symptoms, just not the type they decided to acknowledge).

      The Pfizer and Moderna vaccines are utterly different technologies than the J&J vaccine, so your questions about the # of shots is really off base.

    3. Beth

      The adenovirus vector vaccines hope to avoid the problem of pre-exisiting immunity to these cold viruses by uses obscure and chimpanzee adenovirus. However, there is widespread adenovirus immunity in the population and the injected virus may sufficiently resemble what we have been exposed to to render it completely disabled as a vaccine. And you cannot boost an adenovirus vaccine with another – the second will be disabled by immunity to the first. Many old people have more exposure to adenoviruses and thus have lower immune response from this type of vaccine.

  7. none

    I’ve heard from a few places that the side effects to the second Moderna shot (I’d expect Pfizer to be similar) are often worse than the first. That is not so surprising since when the second shot is received, the antibodies produced by the first shot launch a bigger immune reaction.

    Although Pfizer’s clinical trials didn’t measure asymptomatic infections of vaccinated people, it really does seem to slow down all infections, per data from the Israeli rollout.

  8. bassmule

    Based on a sample size of 6, none of my geezer buddies had any reaction to the second Pfizer shot. I’m getting my second mid-March. As I type, there is someone on NPR blathering about which vaccine is safer, more effective, etc. Trying to make a news story out of not very much at all. (Turns off radio.)

    1. Yves Smith Post author

      Your sample is not representative. It is true that geezers are less likely to have serious reactions due to having weaker immune systems. But see readers above having some marked reactions from their old buddies. And that can include anaphylactic shock. The emergency tracheotomy mentioned above was administered to someone living in a retirement center.

      1. bassmule

        Yes, I do know it is not representative! That’s why I posted the number. I don’t see anything that is not anecdotal about adverse reactions in the story. I went looking for actual stats, and found this:

        featuring this disclaimer: “The Vaccine Adverse Event Reporting System (VAERS) database contains information on unverified reports of adverse events (illnesses, health problems and/or symptoms) following immunization with US-licensed vaccines. Reports are accepted from anyone and can be submitted electronically at”

        Is there a better source?

  9. Fern

    We just completed our Pfizer series. I actually had a worse reaction after the first dose — slept for the better part two days and had a deep somewhat excruciating ache deep in my upper back/shoulder area on the side of the injection along with some random shooting pains in various places. Never took a painkiller, just drifted in and out of sleep. No fever; all and all not very bad. No muscle pains for the second dose — just the overwhelming fatigue again. I was quite grateful to have the vaccine. I know some young people who had a very rough time after the second dose. I wonder if we’ll eventually decide that it’s better for young people to take only one dose?

    When it comes to the fear factor, I don’t feel any less safe with the Pfizer than I would with the Johnson & Johnson. I take some superstitious comfort in knowing that the Pfizer/Moderna spike protein RNA instructions stay in the cytoplasm, whereas the Johnson & Johnson spike protein instructions are encoded in the virus DNA and actually enter our cells’ nucleus, so for me there’s less “ick” factor. But I would eagerly take either vaccine. In my covid risk category, the benefits seem to greatly outweigh the risks.

  10. Jack

    Thank you for posting this article. I am rapidly reaching the point where I do not trust anything the US government or the CDC says about Covid or the Covid vaccine. I really feel they have been duplicitous and incompetent in dealing with this crisis. As the post here suggests and the comments reinforce, what we are being told about the various vaccines is suspicious. For another example of why caution is indicated, take a look at the VAERS (Vaccine Adverse Event Reporting System) data which is a .gov website. The adverse reaction reports concerning the Covid vaccine and related deaths from same are off the scale. Covid vaccines vs. the death rate resulting from the influenza vaccine (the closest comparison) have a death rate that is 48% higher. As of 2/4/21 VAERS had received 12,697 injury reports and 653 reported deaths due to the Covid-19 vaccine. If you look at all the vaccine reported deaths between Jan 2020 and Jan 2021 Covid-19 accounts for 70% of the annual vaccine deaths. Keep in mind that the Covid-19 vaccine had only been available two months of that reporting period. Another point to keep in mind is that VAERS data is a voluntary reporting system. Research has indicated that only 1% of the actual adverse reactions are reported. On a more anecdotal note, I personally know 6 physicians well enough that we are on a first name basis. 5 of them have told me no way, no how are they getting the Covid-19 vaccine based on what they currently know about it.

    1. flora

      I’m still evaluating as much info as I find for my own situation. Reading stories about Pfizer bullying countries and demanding pretty outrageous collateral of a country’s assets as an indemnification pledge, far beyond the normal level of country vaccs indemnification contracts (from what I’ve read), should things go wrong with the vaccs program does make me wonder….

  11. rusti

    By contrast, Pfizer used the dodgy approach of testing ONLY participants who developed “severe respiratory symptoms”. That means they ignored cases with loss of smell, the most reliable indicator of Covid, ones with digestive symptoms. and other symptom combinations that the CDC (and people I know) have found to be signals of Covid onset: fever, chills, headache, fatigute.

    Is it really as bad as this? I have a tough time interpreting the study protocol. Section 8.1 says anyone who developes “acute repiratory syndrome” (nothing about severity) should get a PCR test, then refers to section 8.13 (pages 93-94), which includes all of the symptoms you mention.

    For this efficacy metric, “To evaluate the efficacy of prophylactic BNT162b2 against confirmed COVID-19 occurring from 14 days after the second dose in participants without evidence of infection before vaccination” it would be completely indefensible if they were conducting the trial as you suggest, so it’s scandalous if you’re right.

      1. Zamfir

        As I read it: They define 2 forms of covid, one is a positive test plus one of the following:
        A diagnosis of COVID-19;
        • Fever;
        • New or increased cough;
        • New or increased shortness of breath;
        • Chills;
        • New or increased muscle pain;
        • New loss of taste/smell;
        • Sore throat;
        • Diarrhea;
        • Vomiting.
        And people are told to contact ‘the site’ if they develop any symptom on the list. This one seems to be “acute respiratory syndrome'”, but the link is slightly vague (the list is mentioned in both 8.1 and 8.13, and the “acute respiratory syndrome'” refers to 8.13, but not explicitly to the list). In any case, people who report these symptoms get tested , according to the protocol.

        They also call something “severe” which has more serious symptoms in its definition.

        My impression is that they get better numbers by relying on self-reporting of symptoms, where some of the other trials had regular resting even of people who did not report symptoms. So they miss the mildest cases, where all the vacines seem to score lower in.

        1. Cuibono

          dont forget that all of this data then goes in to the ‘Adjudication committee’ to decide of it was a case.

        2. Yves Smith Post author

          Please stop.

          From what I can tell, as confirmed by the FDA’s EUA, Pfizer tested ONLY for participant-reported cases of respiratory infections, not the other symptoms.

          You are correct in that I mis-recalled the exact language, although some popular write-ups also used the word “severe” rather than “acute”. Perhaps that was due either or both of the S in SARS being “severe” and that given that everyone was tested and presumed healthy before entering the trial, any respiratory infection could not be chronic.

          From page 13 of the FDA EUA memo:

          If, at any time, a participant develops acute respiratory illness, an illness visit occurs. Assessments for illness visits include a nasal (midturbinate) swab, which is tested at a central laboratory using a reverse transcription- polymerase chain reaction (RT-PCR) test (e.g., Cepheid; FDA authorized under EUA), or other sufficiently validated nucleic acid amplification-based test (NAAT), to detect SARS-CoV-2.

          I see nothing that contradicts this in the study protocol. I do see (p. 22):

          a. The COVID-19 illness visit may be conducted as an in-person or telehealth visit.

          That is even less encouraging since Pfizer clearly can’t do a swab remotely. Those brain stab swabs are impossible to self-administer.

          Thus despite all the blather in the protocol about symptoms (which Pfizer gathers by an e-diary), there is a noteworthy absence of what it takes for an actual test is administered to be administered. No positive test, no confirmed Covid case.

          I could find that only in the EUA, and that said only acute respiratory illness.

          Given how exhaustively detailed the protocol is, you think it would be explicit as to what it would take to trigger a test and how promptly it would be administered.

    1. NullandVoid

      I’m positive for Covid antibodies, and I never had any respiratory symptoms, much less severe. I did have diarrhea for 7 weeks last year, with a fever at the onset and again at the end. I never got tested because i never suspected Covid until after it was over, & it’s possible I might not have tested positive anyhow.

      This study appears to explain the manifestation of my Covid infection:

  12. orlbucfan

    Thanks for the excellent informative read, Yves. I am an aging geezer with a compromised immune system. Already got the first dose of the Moderna vaccine. I finish up next week. I just had a sore arm for a couple of days. Several people including a medical professional have warned me about the side effects possible with the second dose, so I am readying myself. The major headache for me has been wading through the media swamp and loud noise from all the lies and misinformation out there. Zeynep Tufecki’s very good article in The Atlantic spells out this problem, plus the politicization of the virus. It is that bad. Is there a solution?

    1. Yves Smith Post author

      As indicated above, you are less likely by virtue of age as well as by having a less robust immune system to have a bad reaction, so enjoy the upside of your condition!

    2. Leftcoastindie

      Same here. My arm hurt more than a flu shot – couldn’t raise my arm over my head for a couple of days and had head aches for a few days as well. Get my second Moderna shot next Tuesday. Should be interesting.

  13. John A

    I had the first shot of the Oxford AstraZeneca vaccine 2 weeks ago. No reaction at all and the second is scheduled for end of April. As I am pretty much isolating except for walks in fresh air and food shopping, I am not much exposed to potential infection so cannot comment on possible efficacy.

    1. Yves Smith Post author

      I haven’t much of anything re the propensity of the Oxford/AZ vaccine to lead to adverse reactions. My impression is it is generally a bit (maybe more than a bit) better tolerated than the mRNA vaccines, but can anyone who has been following the data confirm or correct?

  14. TroyIA

    In my area the school had to cancel in person learning because so many teachers had a severe reaction.

    On a personal note about 2 1/2 weeks after receiving the first Moderna dose my father had a hypertensive episode but luckily we got him to the emergency room before he had a stroke. It may have had nothing to do with the vaccine but it is strange because after countless visits to the doctor for prostate cancer treatment he never once had any indication of high blood pressure. Plus he is on no medication and he even rides his exercise bike for 10 miles almost everyday.

  15. Matt Chambers

    My wife and I, both in our early 60s, are participants in the J&J two dose trial. We just got shots Friday. My wife didn’t have any side effects. I thought I had a mild temperature and very slight chills Friday night, but my temperature Saturday morning was in the normal range, albeit on the high end.

    Even if we got placebos (insert Steve Martin joke here about being really high), we will get a single dose of the vaccine when we get our second shots in April. If we get two doses, hey great.

    I think the folks who think the J&J vaccine is inferior to the Pfizer and Moderna vaccines aren’t reading the data carefully. Yves’s intro above explains why there’s no reason to think the vaccine is inferior.

  16. Jeremy Grimm

    The Pfizer and Moderna vaccines encapsulate mRNA into a lipid-based carrier. The Johnson & Johnson vaccine packs viral DNA into an adenovirus carrier. [“…and replaced a small piece of its genetic instructions with coronavirus genes for the SARS-CoV-2 spike protein.” Can I assume Johnson & Johnson’s replacement of genes in the harmless adenovirus DNA with Corona virus spike-genes somehow disables replication of adenovirus proteins?] As a layman, I remain mystified why all this mRNA and DNA magic is used to manipulate human cells to construct Corona spicules. What prevents using mRNA or DNA carriers to trick yeast cells or E. coli cells in vats to manufacture Corona spicules and harvest the spicules for use as antigens? Is it a concern that some human immune systems might create antibodies to the end of the spicule normally attached to the Corona particle? The Johnson & Johnson “…vaccinated cells make and present the spike protein on their own surface….” Does that prevent human immune systems creating antibodies to to end of the spicule normally attached to the Corona particle? The claim made for the Johnson & Johnson vaccine does not clarify how the virus spicules are present on cellular surfaces.

    I am not fond of the way the vaccines available to me seem intent on playing with the mechanisms inside the cells of my body. All the gaming of and unreasonable exactness of the vaccine efficacy claims remind me of the claims made on boxes for “new and improved” toothpastes or laundry soaps. As for other points of comparison, I am surprised that just the logistics problems and expenses related to the Pfizer and Moderna mRNA vaccines did not make their vaccine approach a non-starter. These mRNA approaches seem like rushed half-answers to the full problem.

    1. Alex Cox

      The author asserts that it’s important to have multiple competing vaccines (as opposed, presumably, to a world-wide collaborative effort). However, their link doesn’t support this claim.

    2. J.

      > What prevents using mRNA or DNA carriers to trick yeast cells or E. coli cells in vats to manufacture Corona spicules and harvest the spicules for use as antigens?

      You could do this, but in animal cells, most membrane-spanning proteins have sugars attached (glycosylation). E. coli cells don’t do glycosylation and yeast cells don’t always do it quite the same as animal cells. The protein you get out of yeast or E. coli might also not fold correctly. If you use an incorrectly made protein in a vaccine the recipients won’t necessarily develop good antibodies to the real thing.

      If you put an mRNA or a virus into a human with the gene you are looking for, the human’s cells will make the protein correctly.

      > Does that prevent human immune systems creating antibodies to to end of the spicule normally attached to the Corona particle?

      I doubt the immune system would see it very much, because it’s inside the cell away from the immune system. The business end is exposed outside the cell and that is what the immune system would primarily respond to.

      I think both adenovirus and mRNA vaccines are an attempt to get a general system you can plug new antigens into quickly.

      1. Jeremy Grimm

        I appreciate your answer although it only raises more questions. On making a careful reading of my original comment and your comment in response I worry that I cannot write more clearly. However, I infer from your answer that for the present and near term the only vaccine choices on offer will involve trusting some monkeying with the internal workings of my cells. But unlike the result of a virus ‘hi-jacking’ of my cells the products should be nicely engineered antigens.

        If yeast and E. coli have so many difficulties making human proteins I can only wonder why efforts should not be made to find and cultivate other more suitable organisms. I also infer more generally from your answer that the general claims of how well researchers understand what they are doing playing inside cellular machinery might be a little ‘optimistic’.

  17. Fred

    Thank you for a good write-up. Very informative. My conclusions are that there are three options for me:
    1. Significant social isolation probably for another 12-15 months.
    2. Let nature take its course and get infected sooner or later. Probably won’t die, but the incidence of long-term lung injury is high.
    3. Get vacced knowing that all of the vaccines are young and none have undergone the full approval process due to the rush to get a product into the population.
    There are probably options 4, 5, and etc that I don’t see.
    I’ve already made a decision.

  18. Mikel

    I still hope that things like ventilation and other safety measures in businesses and public spaces don’t fall by the wayside. There are so many things that need to be done to mitigate the spread of disease for when the next pandemic comes along and there is lag time between that and other treatments, vaccines, etc.

  19. Susan the other

    Thanks for this info. I’ve decided against the AZ vcxx as there was some negative press and not much info to follow. Plus all the chaos in the factory in India and what seemed to be almost pharma sabotage. But who knows? Anyway I’ve decided to take the Johnson. Great name, no? My choice is based on all my weird reactions to damn near everything and an overactive auto-immune thingy. And since the second Moderna can sometimes be dangerous I’m looking into getting Bill the Johnson as well, instead of his second Moderna. That’ll be a question that will get me lotsa blank stares before I decide it’s OK to mix the two, but I think I read somewhere that it is OK. I’ll comment if and when I find out.

  20. KB

    I can’t wait for the J&J vaccine to be delivered here in Minnesota..I have had anaphylaxis reactions to several drugs including aspirin. Running it over with my MD of over 20 years she suggested I stay away from the only one delivered to her clinic, the Pfizer vaccine..In Minnesota 98 percent of fatalities are over age 50, and 89 percent of fatalities to date are over 50….Our allocation system is too complex and confusing. Meaning many seniors have yet to be vaccinated. I called the MDH (Minnesota dept. of Health) myself to ask if I could be put on some sort of list (I’m almost 69)…answer: No…in fact two human beings at the dept. told me they’d never heard the question even asked. I asked them both to let the Governor know, who is the one allocating the vaccines, that many seniors have anaphylaxis in their medical histories!…Thanks, Yves…I just hope they give the J&J to seniors first priority.

  21. Michael K

    My 57-year-old brother had his second Pfizer shot a few weeks ago. He was flat on his back for 4 days. He had Covid last April and was quite ill for about 2 weeks. There are now recommendations that Covid survivors not get a second Pfizer/Moderna shot, since their immune systems have already been primed by their previous exposure.

    Given their generally more robust immune systems, I wonder if younger people should get the J&J/AZN vaccines rather than the mRNA ones.

  22. anonymous

    A few additions and answers to other commenters:
    (1) According to the presentation at the VRBAC meeting, Johnson & Johnson chose to try a single dose vaccine to meet the WHO targets. You can find the WHO targets here: 
    That said, the prime-boost strategy for vaccination is very well established, the mRNA vaccines (like other older vaccines) have been shown to produce an enhanced response with a second dose, and the J&J may be found to have even higher efficacy when the two-dose studies are in, although I have read that there is less of an antibody increase with a second dose of J&J vaccine than with the mRNA vaccines. For J&J, links for the written sponsor and FDA documents, links to watch video of the VRBPAC Feb. 26 meeting, and an update on variants that was included in the VRBPAC meeting can all be found here:
    (2) In addition to the reasons given in the post on why it is difficult to compare the efficacy of the J&J and mRNA vaccines, including the increase in the prevalence of variants during the time of J&J trials, Shane Crotty has postulated that it is harder to prevent Covid cases during surges, and the J&J trials were done during periods of high transmission: (see his embedded Jan 31 tweet)
    (3) The optimal timing of a second dose is still an open question. Michael Osterholm, in many of his recent CIDRAP podcasts ( – transcripts can be downloaded), has expressed his concern over the B.1.1.7 variant and has called for more of the elderly at risk to be given a first dose before giving out second doses; Osterholm has calculated that postponing a second dose in order to vaccinate more people would save lives. He has said that studies were not done comparing intervals for optimal timing of the mRNA vaccines, and that experience with most other vaccines would suggest that the doses can be spread out. The 3- and 4-week intervals for the mRNA vaccines were pushing the timing of doses as close as possible to complete studies for an EUA. The J&J vaccine shows increasing antibody for a couple of months following vaccination, and the AstraZeneca vaccine showed more protection when the second dose was given at 3 months than at 6 weeks:
    (BTW, the B.1.1.7 variant was reported as 1.5 times more transmissible and up to 1.7 times more likely to result in hospitalization and death at the VRBPAC meeting last week:
    (4) I think the two current mRNA vaccines are very similar, but there might be an important difference between the J&J and the AstraZeneca adenovirus vector vaccines. Jason McClellan, on a recent episode of This Week in Virology, said that the Pfizer and Moderna mRNA, the J&J, and the Novavax (protein, still hasn’t applied for EUA) vaccine all used the stabilized prefusion spike protein, but AstraZeneca did not. Prior vaccine research has shown significantly higher neutralizing antibody titres using a stabilized prefusion conformation, so Barney Graham’s NIH lab and Jason McClellan’s lab at UT Austin collaborated on such a spike protein for the SARS-Co-V-2 vaccines. I wonder if the reported lower efficacy of the AstraZeneca vaccine is related to this (my question – McClellan did not comment). Some people might be wary of J&J because they view it as the same as AstraZeneca, which has gotten some bad press. Here is the episode of This Week in Virology in which the spike protein was discussed with Jason McClellan:
    The link includes references, and you can easily find more papers online on the prefusion stabilized spike protein. According to the J&J documents from the VRBPAC meeting, J&J did test different versions of the spike protein before selecting the one used in its vaccine.

  23. Hayek's Heelbiter

    Can anyone in the great NC Hive Mind comment on the Sputnik V vaccine? We get some news about it here (most fairly positive), but I suspect over there you are not getting a single whiff of information regarding this particular vaccine.

  24. Sara K.

    My parents (who are in the 71-75 age range) got the second Moderna shot a few days ago, and they were very tired (as in, much more tired than normal) for an entire day, much stronger than their reaction to the first shot. The next day they felt much better. So yes, 70+ year olds can react strongly to the second shot. Hopefully this means that their immune systems are relatively robust for their age.

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