Johnson & Johnson Vaccine Concerns

CDC and FDA have recommended a pause after one in a million issues with blood clotting.

CNN (“CDC and FDA recommend US pause use of Johnson & Johnson’s Covid-19 vaccine over blood clot concerns“):

The US Centers for Disease Control and Prevention and the US Food and Drug Administration are recommending that the United States pause the use of Johnson & Johnson’s Covid-19 vaccine over six reported US cases of a “rare and severe” type of blood clot.

The six reported cases were among more than 6.8 million doses of the Johnson & Johnson vaccine administered in the United States. All six cases occurred among women ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination, according to a joint statement on Tuesday from Dr. Anne Schuchat, principal deputy director of the CDC and Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research.”

CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance,” the statement said. “FDA will review that analysis as it also investigates these cases. Until that process is complete, we are recommending a pause in the use of this vaccine out of an abundance of caution. This is important, in part, to ensure that the health care provider community is aware of the potential for these adverse events and can plan for proper recognition and management due to the unique treatment required with this type of blood clot.”

NBC (“Johnson & Johnson vaccine should be paused in U.S. after ‘extremely rare’ blood clots, FDA and CDC say“) adds:

In a statement, Johnson & Johnson said it was aware that blood clots had been reported with some Covid-19 vaccines, but that “no clear causal relationship has been established between these rare events” and its shot.

“We continue to work closely with experts and regulators to assess the data and support the open communication of this information to healthcare professionals and the public,” it said.

I’m not a medical doctor but, honestly, 6 incidents out of 6.8 million doses strikes me as an acceptable risk. If anything, the obvious recommendation would be for women to seek alternative vaccines.

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James Joyner
About James Joyner
James Joyner is Professor and Department Head of Security Studies at Marine Corps University's Command and Staff College and a nonresident senior fellow at the Scowcroft Center for Strategy and Security at the Atlantic Council. He's a former Army officer and Desert Storm vet. Views expressed here are his own. Follow James on Twitter @DrJJoyner.


  1. OzarkHillbilly says:

    To repeat myself, it’s an overreaction.

  2. 6 cases out of 6,800,000 is .000088%

    This seems like an overreaction that will lead to vaccine hesitancy.

  3. Barry says:

    @Doug Mataconis: Welcome back, Doug!

  4. Kathy says:

    Yes, the incidence is small*, but a similar issue, small incidence and all, is present with the AstraZeneca shot, another virus vector vaccine. So there does seem to be a “there” there. It is worth taking a harder look as to possible causes.

    *It’s likely there have been more people with blood clots, but these caused no adverse consequences and were not noticed.

  5. Michael Cain says:

    If they’re willing to assume the risk is for 18-48 year old women — if it’s not considered significant, why mention it? — why not keep vaccinating a million men of any age, or old women, each week? Although there may not be a huge number of doses available given that 15M were ruined by the contract manufacturer early this month.

  6. Jen says:

    @Kathy: I’m curious as to how similar the issues between the Astra Zeneca vax and J&J are.

    As I noted in the other thread, women 18-48 is an interesting impact group, because of the link between blood clots and hormonal birth control. Six people obviously isn’t enough to draw any broad conclusions, but if more cases surface exclusively among women in that age bracket, I’m going to be even more curious.

  7. MarkedMan says:

    @OzarkHillbilly: @OzarkHillbilly: I wouldn’t call it an overreaction. J&J did clinical trials. Those trials did not reveal this risk. Now that this risk has been identified, it calls into question the clinical trials. They must be reexamined to make sure no mistakes were made. Also, now that this risk is known, the review process must be repeated with this as a known risk to decide if the benefits outweigh the risks. The previous risk analysis was done based on non-fatal side effects and now it must be redone. Since it involves fatalities it is usual that product use is put on hold until all of this has been completed. This is the normal and right reaction.

    One of the hardest things for the Medical Device engineers I worked with to wrap their heads around was that it wasn’t the goal of a risk analysis to come up with “no risk”. The stereotypical example is a hospital bed. Can a hospital bed cause a fatality? It is very tempting to put on your FDA submission a “No”. But the reality is that given the number of people in a hospital bed every day, beds cause deaths every year. For example (real case), the nurse had threaded life support equipment supply lines through the side rail. It wasn’t latched correctly and the rail later came down, disconnecting the equipment. So if I submit a new bed and say there is zero risk of fatalities and then later there is a fatality that the bed played a part in, it tells the FDA that my risk analysis was wrong. What else is wrong with it? The bed may be no more dangerous than other beds, but I’ve demonstrated with certainty that my risk analysis is inadequate. And in the US system, the FDA doesn’t do independent risk analysis. That analysis is done by the submitter.

  8. Nightcrawler says:

    I got the J&J on Saturday. I’m not concerned. In fact, I’m glad I got mine before they paused it.

    The chances of me getting a blood clot from this shot are far lower than dying or, worse, becoming a long-hauler after being infected.

  9. CSK says:

    There are incidents of women on birth control pills developing blood clots depending on the level of estrogen in the pill. But again, this is rare: you have a 0.3 to 1 percent chance over the course of ten years.

  10. Kathy says:


    It would seem natural to focus on the viruses used as vectors, and to look at any other virus vector vaccines as well*. but it might be how they produce the spike proteins. If there is an adjuvant, is it the same in both vaccines?

    That’s my minimally informed layperson quick take. No doubt clinical researches, who actually know about blood clots, can think of better avenues for investigation.

    *ALL virus vector shots, not just those for COVID-19.

  11. KM says:


    J&J did clinical trials. Those trials did not reveal this risk.

    The thing is, trials won’t and can’t be expected to catch everything. What’s interesting (and not always being reported in the OMG PROBLEM!! hysteria) is that thrombocytopenia (low platelet count) is being reported along with the clots in the afflicted individuals as well. This is usually a symptom of a pre-existing problem or indicative of certain drugs being taken aka people not likely to be in a drug trial. Things like bone marrow disorders and anemia (something more likely to afflict women) can cause this so it’s not surprising to see it in younger, menstruating women likely on some form of hormonal BC as anemia is known to happen.

    In other words, it’s looking like the problem is with the patient, not the vaccine and it’s likely a recommendation will be made for people with X issue or on Y medication not take J&J shots just to be sure.

  12. Daryl and his brother Darryl says:

    Is the risk infinitesimal? Yes.
    Was this handled perfectly? No.
    Am I glad about the transparency, and happy the former guy isn’t still in office lying about everything? Damn tootin’.

  13. Daryl and his brother Darryl says:

    @Daryl and his brother Darryl:
    Apparently this pause is only to alert Medical types about how to treat this rare type of clot, and is expected to only last a few days.
    I do hope that this doesn’t drive anti-vax hysteria…but I’m sure Fox News and the right-wing echo chamber will make hay over this.

  14. Bob@Youngstown says:


    Now that this risk has been identified, it calls into question the clinical trials. They must be reexamined to make sure no mistakes were made.

    Random thought:
    Would the clinical trial have caught this if the trial period (before EUA issued) were the planned 2 years? — my gut says no.
    Would the clinical trial have caught this if the total number of trial participants were increased (say from 30,000 to 500,000)? – possible, but chances are no.
    Would the clinical trial have caught this if there had been 30,000 participants who were women 18-38? – possible but still chances are slim.

    While as James calculates the incidence may be 6 out of 6.8 million, what is missing in the calculation is the number of 18-48 year old women who have taken the J&J vaccine.

  15. KM says:

    @Bob@Youngstown :
    Depending on the issue, they might have been deliberately excluded from the trial since some medical issue render you a poor choice. For instance, thrombocytopenia is known to happen in immuno-comprised folks like those taking chemo – not someone you’re going to see sign up for a vax trial and would likely exclude as nobody should be getting vaxxed normally in that state. Trials try to catch a wide array but there’s some states you don’t expect something to be admitted in (like pregnancy) so you lose out on that one in a million combo that could product the negative results early.

    6 out of 6.8 million sounds about right for a small pool of individuals with a fairly rare pre-existing problem and on a specific drug with a small percentage being likelier to clot. I’m sure there were more individuals out there who possibly met these conditions and were vaxxed but all the stars aligned for these 6 women.

  16. In a morning press conference the CDC stated that the pause was just a recommendation, not s mandate

  17. Slugger says:

    Definitely a rare event, and it may simply reflect the stochastic occurrence of clots in any population. However, caution is appropriate when giving a mass treatment to a healthy population. I did find this:
    A report of this peculiar type of clot in one out of 214 people in India receiving a tuberculosis vaccine. Random event or class effect of immune system stimulation? It’s worth taking a look.

  18. Jen says:

    @Slugger: That is very interesting, as tuberculosis vaccine (BCG) is currently in trials to stimulate the immune system and pancreatic cells to reverse Type-1 diabetes. (T1 diabetes is an autoimmune disorder in which the immune system attacks and kills the pancreas.) So immune system stimulation is interesting, and women are far more likely to have autoimmune disorders than men (except for T1 diabetes, which is closer to 50/50).

  19. Bob@Youngstown says:

    Moderna and Pfizer published their stage 3 protocol for eligibility/ineligibility to participate in their trials. I’ve not seen the corresponding level of detail for the J&J trials.

  20. Stormy Dragon says:

    Even if the J&J risk is small, when there’s two other vaccines that don’t appear to suffer the same issue, it could still be enough to make it a better choice to wait for the pfizer/moderna vaccine instead.

  21. Jax says:

    @Jen: They used BCG to treat my Mom’s bladder cancer, too. It seems to be useful in a number of ways!

  22. Nightcrawler says:


    In other words, it’s looking like the problem is with the patient, not the vaccine and it’s likely a recommendation will be made for people with X issue or on Y medication not take J&J shots just to be sure.

    That’s why I suspect as well.

  23. Jen says:

    @Jax: I’m fascinated by the studies/uses. As I was born in Southeast Asia, I received BCG as part of my standard vaccination schedule, unlike most kids born in the US.

  24. DrDaveT says:

    I wonder how many people who received the J&J vaccine have since been hit by lightning. Should we be worried?

    Less snarkily, in 2018 in the US 18,000 women died of falls. That’s roughly one woman in 10,000. A woman who gets the J&J vaccine is roughly 100 times more likely to die by falling that year than to suffer a blood clot as a complication. I think we can safely ignore any risk that is 2 orders of magnitude lower than ordinary daily life.

    (Caveat: obviously, if the blood clots are occurring exclusively in people with a specific comorbidity, that’s important information for those people and their physicians. If the purpose of the pause is to establish whether this is the case, that makes sense.)

  25. OzarkHillbilly says:

    @MarkedMan: As Doug noted,

    6 cases out of 6,800,000 is .000088%

    Even counting only women between 18 and 48 the percentage will be very small. Study it? Of course. Stop using it for women 18 to 48? If one wants to be super cautious and thinks a dozen or 3 dead or suffering life long impacts from serious Covid infections is worth the trade….

    Oh wait a minute, that would be really stupid.

  26. Kathy says:


    More snarkily: 100% of the people who receive any COVID vaccine will eventually die.

    Just not likely of COVID.

  27. Gustopher says:

    @Stormy Dragon:

    Even if the J&J risk is small, when there’s two other vaccines that don’t appear to suffer the same issue, it could still be enough to make it a better choice to wait for the pfizer/moderna vaccine instead.

    Given the prevalence of covid in this country, there is a certain point where waiting presents a higher risk.

    One in a million is about 340 people in this country, which is about 1/3rd the number of people who die in a single day from covid. Let’s say this is exclusive to women, so 2/3rds the number of people who die in a single day from covid.

    If offered a choice between J&J vs Pfizer or Moderna, I could see going with one of the latter. Without doing a lot of math, I don’t know how long I would be willing to wait for one of the others though — my guess is that the expected value of death from being unvaccinated for an additional week or two is higher.

  28. MarkedMan says:

    @OzarkHillbilly: You make a good point, but even at the surface, this bears more scrutiny. I can think of at least ten things they would want to do to make sure this isn’t more widespread then expected. But more importantly, there is a set of protocols in place that call for a review in such a case and they cannot easily be overturned. And do we want them easily overturned? Think about the fact that Trump got rid of his competent head of the FDA (Gottleib) and put in a weakling toady. If he had the power to overrule protocols and make arbitrary decisions, where the hell would be right now? Chloroquine Nation?

    If this pause lasts more than a few days it will most likely be because there are questions about the submission or incorrect classification of side effects, not because regulators are a bunch of bureaucrats who don’t care about human life.

  29. steve says:

    “Now that this risk has been identified, it calls into question the clinical trials. ”

    Not really I think. Phase 3 studies in this case had about 40,000 people. That is a lot for a study. Most have fewer. These studies just arent designed to catch problems that occur only 1 in a million times. That is why we do after market monitoring. (Which we don’t always do so well to be honest but thank God we have the socialist countries because they are better at it and catch stuff when we don’t sometimes.)


  30. Dave Schuler says:

    We’ll be completely safe even if it kills us.

  31. Blue Galangal says:


    Phase 3 studies in this case had about 40,000 people. That is a lot for a study. Most have fewer. These studies just arent designed to catch problems that occur only 1 in a million times.

    I logged on to say this and there you were. Exactly. Phase 3 studies aren’t going to catch these extreme tails.

  32. CSK says:

    The latest:

    Donald Trump says Joe Biden is in league with Pfizer to halt the J&J vaccine as a political ploy.

  33. Lounsbury says:

    @Doug Mataconis: This is indeed typical Rich World people, so unexposed to real substantial public health risk that a miniscule .000088% gets the in a tizzy.
    I can assure you in my African offices, there is much eye rolling and general reaction of “then send it here.”

    @Dave Schuler: Yes, better not to take the .000088% risk in favour of the 3.4% risk of death (global blended average)…

    Of course humans are structurally bad at this sort of risk analysis, our over-clocked chimp brains do not naturally correctly interpret risk. Which of course further renders the irresponsibility of the Trumpists and Trump in the Republican party more awful as encouraging further error.

  34. Jen says:

    @CSK: Well, I would say that’s oddly a good thing because it would (somehow?) mean to his supporters the J&J vax is fine, but then again the few that would even consider being vaccinated are opposed to using that one because of the abortion cell line nonsense.

  35. CSK says:

    I don’t think anything, at this point, will persuade the Trumpkins to take the vaccine.

    As a side note, I got an email from Mass. General/Brigham today telling me that if I got the J&J a month ago, I’m safe.

  36. grumpy realist says:

    @CSK: Given that the entire goddamn country of Brazil looks to be turning into a super-spreader event courtesy of its idiot president AND the variant they’ve got looks to be up to 3 times more contagious than the original variety, I suspect we’ll soon be seeing a wave of P.1 rolling through the U.S. as well. Those of us who are vaccinated will probably survive (the jury’s still out on precisely how much the present vaccines will protect against P.1 but it’s the South African variant that doctors seem to be more worried about) but if you aren’t vaccinated? You may have a problem. And it isn’t the death rate I’d be worried about–it’s the “long-Covid” aspects, where you end up with scarred lungs and have to have an oxygen bottle near you for the rest of your life. Or your brain goes flakey and you have consistent and persisting fatigue. Or any of the other charming effects that have been reported.

    But–hey–if you want to have the “freedom” of not getting vaccinated, go ahead. Just don’t complain when the chickens come home to roost.

  37. Pylon says:

    I agree – it is an overreaction that will cause hesitancy. I don’t blame either the government or the industry for disclosing it. I blame the media for the breathless reporting. This is warning label stuff, not lead story stuff.