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Clinical Trials

Moderna’s Upcoming Clinical Trials

One of the ways in which this pandemic will be looked back on as a pivot point will (almost certainly) be in the use of mRNA vaccines. It seems clear at this point that these have come through spectacularly against the coronavirus: every new study of their effects in the broad population just adds to the efficacy story, and safety concerns have been minimal. We are extremely fortunate that this is the case – never forget that. The huge amount of work that’s gone into this platform over the years paid off at just the right time for us to quickly get such therapies into human trials, and what’s more, they worked when they got there. That’s not always the case – never forget that, either. Vaccines for infectious disease have a historic two-out-of-three failure rate in the clinic (which is nonetheless the lowest such failure rate by far compared to all other drug development areas!) We had a substantial leg up on the current virus because of all the work that went into SARS and MERS, but even so we’ve seen coronavirus vaccine failures from large, well-resourced, extremely competent outfits like Merck, Sanofi, and GSK. There is a timeline in which this happened to everybody, and I’m glad I’m not living in it.

Now that we’ve seen this, though, there is naturally going to be a big push for the mRNA platform as a whole. Moderna and BioNTech are of course good companies to watch for such developments. The first of these will surely be continued targeting in immunology. That’s because systemic mRNA dosing is still a real problem – you get far more effect if you can use the technology to leverage the power of the immune system, which is just what a vaccine does, rather than try to soak the whole body in it as a therapy all its own. I wrote here about some recent BioNTech work directed at multiple sclerosis, so today let’s see what Moderna is up to.

The weeds are not growing up around them, that seems clear. This press release updates several long-running efforts of theirs, and you can see the effect of a big infusion of money, capacity, and clinical confidence. Their first update is on mRNA-1345, a vaccine candidate for RSV (respiratory syncytial virus). That one is of special concern in infants and also in the elderly, and there is as yet no vaccine. That’s not really for lack of trying – people have been working on such candidates for many years, but it’s a challenge. This 2020 review estimates that there are 38 candidate vaccines in development (!), and it is clear that (a) not all of these are going to work in the first place, or surely not to the same degree, and (b) the market will end up dominated by whichever of these many candidates can truly stand out in efficacy, ease of administration, and safety.

Moderna is obviously betting that theirs can. They’ve had previous swings at this target (mRNA-1777), but the Phase I data they’re presenting now indicate that the 1345 vaccine leads to much higher levels of neutralizing antibodies, with no safety concerns yet. The fifty-microgram dose seems just as good as the 100-microgram one, so far. This is just a first look in a small number of young adult patients, and there are many more groups being tested, but so far, so good. As with all vaccines and all drug candidates, Phase II is where the bat will make contact with the ball (or not!), and that efficacy data is still some time in the future. There will likely be other RSV candidates before various regulatory authorities (or even approved) by the time Moderna is ready to make its case, and the story will also be how well their candidate compares.

The release also updates data on their cytomegalovirus vaccine (mRNA-1647). CMV is quite common – over half of adults in the US have already been infected, most of them without much incident. The big concerns are pregnant women and immunocompromised adults (especially organ transplant recipients) for which the infection can mean real trouble. This is another area where vaccine work has been going on for a long time, and there are some significant challenges. CMV is a huge virus, and codes for over two hundred proteins, a ridiculously large number by viral standards. Which of those are the best candidates as vaccine antigens, and how are you sure about that? Right.

Moderna’s candidate actually was the first mRNA vaccine candidate to go into a human Phase II – it made it in just as the pandemic was gathering earlier last year. The interim data show a strong neutralizing antibody response, and the company is moving on with one of the doses (100 micrograms) to a Phase III study in women 18-40. That one will produce preventative data, obviously the key for the whole effort.

The company also has a longrunning flu vaccine program, and that’s a tough place to work in. The existing vaccines hover around 50% efficacy – far better than nothing, but plenty of room for improvement – and the influenza viruses themselves are notoriously good at rearranging their surface proteins season by season. As an aside, we should be very, very happy that the coronavirus does not have these abilities (and no, it’s not going to acquire them suddenly – they’re built differently from the start). One real advantage of the mRNA platform would be shorter lead times for vaccine production. If the damn flu is going to change every time around, which it is, we’d be better off tracking the strains in closer to real time to match vaccine antigens. The Moderna press release says that they heading into Phase I with “multiple candidates”, and they they hope to come up with combination vaccines against flu, SARS-CoV-2, RSV and human metapneumovirus (hMPV) all at once. This is a very worthy goal, but it’s obviously going to take a while.

Finally, Moderna has also had a longtime interest in the HIV vaccine field, and if you want to pick a tough area to work in, that’s the place to be. As the world knows, decades of work have yet to yield a useful vaccine in this area. But over the past thirty years, a great deal of effort has identified several broadly-neutralizing antibody types, featuring rare but powerful binding modes that remain active across many different viral strains. Moderna is going into a range of Phase I trials around their candidate mRNA-1644, partnered with the International AIDS Vaccine Initiative (IAVI) and the Gates Foundation. IAVI and Scripps recently saw good results with the induction of such broadly-neutralizing antibodies, and the hope is that mRNA-1644 can be optimized even past that. This is going to also take a while, but overall the bNAb approach is the most promising HIV vaccine news around. Moderna has another approach being developed with the NIH, mRNA-1574, a multiple-antigen vaccine that will also be moving into Phase I this year.

That’s a lot of trials! I’m glad to see the company moving so quickly and aggressively. They’re clearly putting the money and momentum from the coronavirus vaccine work to good use. And remember, this is just the clinical trial end of things, the tip of the spear, and there is surely a good deal going on preclinically that we’re not hearing about. I wish them, BioNTech, and all the other mRNA immunology developers every success. The acceleration of work in this area is one of the few real silver linings of the pandemic.

51 comments on “Moderna’s Upcoming Clinical Trials”

  1. myma says:

    I think we give these a lot of leeway this year for the side effects of vaccines because getting coronavirus would be worse. But it is worth noting that the 1st dose is okayish and the 2nd dose can be a bit of a doozy the next day, for both Moderna and Pfizer’s. It seems to be inversely proportional to age – the younger ones get the 2nd dose effect much worse than the older ones. I don’t have numbers, and I can’t cite any papers, just a whole swath of friends and family and employees and the extended circle of all of the above on facebook and such. My own 30-40something year old biotech employees usually wind up taking a sick day the day after the 2nd shot. I don’t know if it is thought to be due to the mRNA vaccine technology or due to the fact that it is coronavirus that is being vaccinated against.

    However, I don’t think in ordinary years people are going to tolerate that sort of take a day off the day after thing going on as part of their own mental risk-benefit for taking a vaccine.

    1. Hap says:

      I imagine that depends on the costs of the disease itself, though – against flu it wouldn’t be great because the costs for most people aren’t that high, but for COVID or HIV, or CMV, or RSV I think most people would take some short-term crappy feeling for immunity for them or their kids.

      1. CET says:

        Agreed. Although given that I had almost a week of epic headaches and a lymph node the size of a golf ball after my second COVID shot, I’d think twice about doing it again for HIV and CMV given that one is pretty low risk of contraction for my lifestyle and the other is…more or less ubiquitous?

      2. Einstein says:

        By 2 years of age natural infection with RSV is almost 100%, do we need to routinely vaccinate against this virus at all? With <500 death per annum in the US, almost exclusively in high risk infants so these vaccines will need very stringent and very long term safety evaluation before routine use. The bar for safety is very high – just restating the obvious and what was overlooked for covid is not for these other programs.

        1. Peds says:

          If you go to a pediatrics floor in the winter, more than half of the admissions will be babies on O2 for a few days due to RSV. Luckily the vast majority don’t die but there is a significant healthcare burden

    2. WetDog says:

      Do recall that both Moderna and Pfizer settled on dosing their vaccines on the ‘hot’ side because they were more worried about efficacy during a pandemic situation than side effect profile.

      I do believe that trials of lower doses of both formulations are being done (NCT04813796, NCT04713553 and others).

      And, as a vaccinator, I’ve seen results of direct questioning after first dose and telephone surveys of second doses of both mRNA vaccines as all over the map.

      Many patients have compared them favorably to the shingles vaccine and some influenza vaccines. It would be most interesting to see a real study on this, but I tell people it’s 1/3 better, 1/3 worse, 1/3 no change. Just like most things in medicine.

      1. Aleksei Besogonov says:

        To add a personal anecdotal data point, after the last flu vaccine I couldn’t sleep normally for two days because my whole upper arm was constantly in pain.

        After both Moderna shots I got tender spots on my arm (as if I bruised it) for about 3 days. No other effects (maybe a bit of fatigue, but this might also be explianed by vaccinations being scheduled on Mondays).

      2. debinski says:

        I have been wondering why Moderna dosed at 100ug while Pfizer uses only 30ug? If you look at phase 3 data from both, Moderna does have a slightly higher AE %, especially after the 2nd dose. From personal experience (self, family and friends) I’ve gathered that Moderna side effects may be substantially worse (maybe not %-wise, but severity-wise). My experience with the Pfizer vaccine was that the AEs were milder but lasted longer after the 1st compared with 2nd dose and neither was as bad as the first Shingrix vaccine. I never got up the nerve to get the 2nd Shingrix. Not a fan of adjuvants!

        1. Patrick says:

          Well, the Moderna vaccine appears to induce somewhat higher levels of antibodies than the Pfizer one. Because there’s no difference in measured efficacy, the mRNA vaccines seem to be out on the edge of possible clinical efficacy from the approach they’ve taken (they provide the same spike protein antigen, so the main difference is likely in level of antibodies induced).

          So my guess is some mix of A) they aimed higher out of caution, B) Pfizer may have had some expertise that gave them greater confidence in going with a lower dose (30 micrograms), and C) the formulations are similar but certainly not identical – it’s possible the Pfizer/Biontech mRNA dosing formulation gets more “bang for the buck” in terms of immune response per unit of mRNA than the Moderna one.

          1. Patrick says:

            Source on higher antibody levels from Moderna vaccine – these clever folks compared antibody levels from the various vaccine trials by normalizing them to the convalescent serum panels also reported in each trial. Not perfect, but should *mostly* eliminate issues with different assays.


            (This is my favorite pandemic related paper I’ve read, hands down, other than I suppose the very happy experience of the mRNA vaccine trial results.)

    3. Aleksei Besogonov says:

      Possibly it’s the amount of antigen (100ug) in Moderna/BioNTech vaccines. For comparison, flu vaccines are around 45ug.

      No doubt, Moderna will spend a lot of time optimizing the components further.

      1. Mantis Toboggan says:

        Unless I am misinterpreting this is an apples and oranges comparison. mRNA vaccine doses refer to amount of mRNA and not antigen. Antigen is produced from the mRNA. Flu vaccines are not mRNA vaccines, so you can’t compare them in the way that you have, unless you are referring to 45 ug of an mRNA flu vaccine.

        1. Marko says:

          Yes, and in order to compare antigen levels fairly, we’d need to have some idea how many spike copies are produced per mRNA copy before the mRNA craps out. I’ve looked around a bit and haven’t found anything about this, but my guess is it’s on the order of at least tens of copies of spike per mRNA , which, if true, would easily tip the all-in antigen load scale to the side of the mRNA vaccines.

          1. Ildanach says:

            On the other hand, MRNAs are much larger than the proteins they code for!

          2. Marko says:

            That’s true. It would take ~10 copies of spike per mRNA to make up the difference on a mass basis, but I think that’s in the lower range of what’s likely. I’ve seen estimates for other human mRNAs that run into the range of 1000 copies of protein per mRNA copy.

            Lots of variables involved, like what’s the proportion of injected mRNAs that actually make it to the translation stage, so outside of some direct measurements, we’ll probably never know.

      2. Patrick says:

        The Pfizer/Biontech vaccine only uses 30 micrograms. That’s usually assumed to be part of the better side effect profile.

    4. Stephanie says:

      I’ve delayed my Shingrix for this reason, but I would rather take a day off than be utterly miserable for a week or longer. So, trade-off. I disagree that the vax is worse than the disease but for many things, people will decide individually. On the other hand, many of these vax may be administered to children anyway? I am hopeful and optimistic that mRNA will bring humans many healthy days!

      1. Derek Lowe says:

        My second Shingrix dose was a very sore arm a bit of tiredness. My wife felt for a day or so as if she were coming down with something (along with a sore arm), but nothing worse. It’s quite an adjuvant, though – I rarely have any vaccine reactions, so this one was my record. Second Pfizer mRNA shot is coming up next week.

      2. myma says:

        (my apologies, perhaps I was unclear – I agree that a day or so of 2nd dose misery is far far better than the unknown probability of long hauler disease, unknown probability of tissue necrosis seen and unseen, unknown probability of serious autonomic nervous system dysfunction, brain and memory problems, and 2% chance of death.)

        To others points above: I am too young for shingles vax, but I am definitely getting that, as I have seen first hand in older relatives how debilitating shingles can be. I am not the demographic for HIV or for complications from CMV.

        My kids are beyond RSV age (though worth noting my daughter did have RSV and the associated pneumonia). If 30-some year olds =seem= to get the 2nd Dose misery worse, we shall soon see what happens when mRNA for Covid rolls out to 20’s and teens and then kids. In any case, getting on the pediatric vaccination schedule is always a challenge.

      3. KazooChemist says:

        I had the Zostavax vaccine (with few side effects) and then was among the lucky ones who proved that the vaccine was only about 50 % effective at preventing shingles. My case of shingles was apparently on the mild side in that I suffered merely extreme pain on my chest, back, and arms, not excruciating pain. When you cannot bear the weight of a single sheet on your chest you know you are in pain. I got the Shigrex vaccine as soon as it was available (again with few side effects) and would recommend that everyone do so when they are eligible. For me the hepatitis B vaccine was the real killer.

    5. Charles H says:

      FWIW, and given the “efficiency figures”, I think the makers high-balled the vaccine dose, to be effective in those with weak immune systems. A “calibrated” dose would probably have much milder effects.

      OTOH, I’m a programmer, not a medic or biochemist.

    6. x says:

      You must be new to this planet. I’ve been held down and punched repeatedly in the arm by tetanus boosters, and that was decades ago. This “feel crappy the next day” thing is nothing new for vaccines and I don’t expect it to significantly blunt adoption.

    7. Bob Marlee says:

      It’s possible, and indeed even recommended, to administer multiple vaccines at once. If mRNA proves to open the door to rapid development of many new and effective vaccines, what’s the harm in taking one sick day a year to get dosed against the latest influenza and COVID-19 variants, other boosters and new vaccines?

  2. bacillus says:

    mRNA vaccines only have a chance of working if you know what antigens elicit a protective immune response. This is unknown for many pathogens, especially bacteria. Several current live attenuated vaccines can elicit lifelong protection after a single dose, often by evoking a life long T cell response. Thus, until mRNA vaccines prove their worth against these issues, they won’t be the only game in town. When the first purified protein vaccines hit the market a couple of decades ago, they too were lauded as the only way forward.

    1. Kent Matlack says:

      One thing that needs focused effort is stabilizing mRNA-based vaccines so that storage and cold chain issues are decreased.

  3. Blaine White, M.D. says:

    The mRNA vaccines have indeed performed very well. I’m a retired Emerg Med prof with no ties ever to any of the vaccine producers, and I write that because I am becoming increasingly concerned about the adenovirus vector vaccines. Yesterday (4/20/2021) a new bench science paper from Germany examining the J&J vaccine appeared on a preprint server – Greinacher A et al. Towards understanding ChAdOx1 nCov-19 Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT). Research Square 2021; I am not convinced by its argument for the etiology of VITT, but it contains compelling evidence of the presence in this vector vaccine of many proteins other than those of the DNA adenoviruse containing the Spike code, and most – or all – of these extraneous proteins are human in origin (Figure 2). Furthermore, antibodies in serum from people who haven’t had C19 nor been previously vaccinated recognize a number of those proteins (Figure 5). The heart of this vaccine is of course the engineered DNA adenovirus containing the code for our cells to transcribe the mRNA for Spike and translate that mRNA into the antigenic Spike protein. This adenovirus has chimps for its natural host, BUT production of the vaccine involves growing the adenovirus vector in transformed human embryonic kidney cells. The adenovirus Spike vector is then isolated to produce the vaccine, but this paper shows that isolation does not remove all the human proteins. Indeed, Figure 2 shows that in addition to the vector proteins, just over ½ of the proteins in the vaccine are of human origin!! On top of that, Figure 5 shows that antibodies from 4 C19-naive subjects and 3 VITT patients already recognize at least 4 of the proteins in the vaccine, and that recognition develops the highest titers in the VITT patients. The human-antibody-recognized proteins may be adenoviral in origin, but a vaccine against Spike containing extraneous human and adenoviral proteins our immune systems already recognize is probably not a good idea, and I would now be difficult to convince to approve these. I’m very glad we’ve had the mRNA vaccines as an alternative and remain hopeful for the inactivated whole virus vaccines. I’m not happy about this development and know it will fuel vaccine hesitancy, but we probably need to step away from these adenoviral vectors for now – as the EU has done by cancelling future orders.

    1. johnnyboy says:

      The problem of host-cell protein (HCP) contamination in biological therapeutics is well-known, and one of the many factors evaluated in the quality controls of biologics manufacturing, be they viral vector drugs, gene therapies or monoclonal antibodies. I presume the same QC procedures are being applied to the Covid vaccines, and being reviewed by regulatory authorities. There is a certain level of HCP that is considered acceptable for any biologics preparation. The results shown in this manuscript of WB reactivity of non-vaccinated serum against the AZ vaccine could be showing reactivity to viral proteins, there is nothing there that indicates that the reactivity is to human proteins. The high concentrations of serum used in the WB are pretty suspect anyway, and there are no negative controls shown for non-specific reactivity.

    2. The boss says:

      Spike is non native, immune response roused could cause autoimmunity vs related native proteins (spikes affinity for a ubiquitous receptor and important ACE2 messaging system makes one such potential issue likely). Immunology is unpredictable and any such issues could take years to surface. Unknown territory, large study population

  4. Daniel L Speyer says:

    If we try going mRNA for the annual flu vaccine, what about acquired immunity to the lipid vector?

    Anecdotes about second shots on covid having worse side effects suggest this is a thing, and ISTR B cells can be activated by internal toll-like receptors when peptidoglycan-like molecules are around. This would be way worse with a regular annual shot.

    1. Cole J. Batty says:

      If you are interested in anti-LNP immunity I recommend this paper from Moderna:

      Note that this is analyzing i.v. instead of i.m.

      The reactogenicity upon the second shot does not necessarily suggest anti-vehicle immunity. The simplest explanation would be that this is a reaction to the antigen. This doesn’t mean that there isn’t anti-vector immunity, just that that’s not good evidence for it. One step taken to reduce the potential effects of anti-PEG immunity is to create a PEGylated lipid with a linker between the PEG and lipid which is cleaved hydrolytically or enzymatically upon injection, leaving the particle free to transfect cells while the PEG-Antibody complex does…something else.

      “ISTR B cells can be activated by internal toll-like receptors when peptidoglycan-like molecules are around” This is kind of true but doesn’t specifically have anything to do with what you’re talking about. TLRs, which are triggered by e.g. DNA, RNA, and certain lipids/lipopolysaccharides, cause antigen-presenting cells, including B cells, to secrete proinflammatory cytokines, which can drive a stronger immune response. B cells are activated by recognizing antigens (often polypeptides, glycans, or ‘peptidoglycan-like molecules’) through their B cell receptor.

  5. Andrew Molitor says:

    This is probably a profoundly stupid question, and there are probably much more appropriate places to ask it, but I don’t know where they are.

    Why don’t they just inject a great blodge of spike protein into us, instead of going to an immense amount of trouble to persuade out bodies to manufacture the stuff?

    1. Blaine White, M.D. says:

      That’s exactly what Novavax is trying to do, having made the Spike protein in insect cells.

    2. sgcox says:

      This is also what Sanofi tried but failed. How and why Novavax succeed – please tell me, I earnestly do not know. This is just another fascinating story in vaccine developments in 2020. The lessons will be learned and discussed in details in decades to come, I guess.

    3. Cole J. Batty says:

      As mentioned above, there are multiple vaccines, including the Novavax candidate, which are doing this. Protein expression and purification can be difficult because you need to separate the protein from the cells that make it without damaging the protein. Spike in particular became somewhat notorious for labs at the beginning of the pandemic as it was hard to get high yields of protein and they often were not in the desired prefusion conformation. The S2P and Hexapro modifications developed by Jason McClellan and other NIH-funded researchers have helped with protein stabilization which makes it a better antigen and easier to express in cells, but with mRNA you don’t have to figure out any of these issues and can just make the mRNA using pretty standardized and universal techniques. That being said, the protein expressed from the mRNA by the recipient’s cells still needs to raise the right immune response, so stabilizing it in the proper conformation is still helpful.

      1. Andrew Molitor says:

        Thank you all!

        My vague understanding of mRNA is that it’s remarkably pesky stuff, and I was having a hard time imagining that the protein would be harder to handle (we’ve been purifying proteins fore decades, right? And, often, it’s pretty stable stuff?), but I guess that is the case here?

        I was thinking there was maybe some immunological voodoo that happened when you forced the body to make the stuff up itself, but it seems to be really a question of “no, this is actually the technically simplest way to get a bunch of this crap, in the right shape, into your body”?

        1. Bronstead says:

          So, your body doesn’t always raise a large immune response to free ranging proteins. That’s why we use adjuvants – these are sort of meant to prime your immune system to see these proteins as part of an actual infection. And the response it raises to these free ranging proteins (neutralizing antibodies) is only part of the immune response you see in an actual infection (which also targets infected cells which display these proteins on their surface). When mRNA enters a cell and gets it to express protein on its surface, it ends up looking a lot like an actual infection, raising a robust immune response at multiple levels.

          1. Andrew Molitor says:

            Thank you! That’s very interesting. I am now infinitesimally smarter, and that delights me!

    4. Hap says:

      If it’s a membrane-bound protein (I thought Spike was), then it likely has lots of greasy patches which could lead to aggregation and either decomposition of the protein (if the proteins get stuck somewhere they can react with one another) or agglomeration (where it forms a block that can’t easily be broken apart for the body to use it to generate an immune response).

      1. sgcox says:

        It is a single pass TM, so not too bad in terms of production and purification.
        Clearly a lot of work has been done to make stable formulation (as always).

  6. Marko says:

    Valneva Initiates Phase 3 Clinical Trial for its Inactivated, Adjuvanted COVID-19 Vaccine Candidate, VLA2001

    “…Approximately 4,000 participants will receive two doses of either vaccine. The primary endpoint of Cov-Compare will be to determine the immune response (Geometric Mean Titer (GMT)) of SARS-CoV-2-specific neutralizing antibodies) two weeks after completion of a two-dose immunization schedule administered in a four-week interval. The trial is powered to demonstrate superiority of VLA2001 in terms of GMT ratio (VLA2001/Vaxzevria). The trial will be conducted in the U.K. and is supported by the National Institute for Health Research (NIHR).”

    BPL-inactivated whole virus with two adjuvants, alum and CpG 1018 from Dynavax.

  7. matt says:

    I read recently Moderna and Pfizer were planning to seek approval for coronavirus booster shots this fall. Doesn’t this seem a little premature? There are variants against which the mRNA vaccines are a little less effective, but there’s not much evidence that 1) these variants will be widespread and 2) these variants will present any problem to already-vaccinated people. Obviously, other variants might come along that do present a problem, but you can’t develop a booster against an unknown future variant. So is this just a cash grab? (I can’t imagine the world will be vaccinated up by this fall, so it’s not likely business will be slow then.) Or is there some benefit for a sort of placeholder here in case of future need?

    1. Mariner says:

      I’d imagine they know they can keep getting top dollar from the wealthier countries and that no politician in these countries wants to be seen to be failing to give their voters anything but the best protection.

      The correct thing to do would make the vaccines available to the poorer countries who need them so badly – what is currently occurring in India and many South American countries shows what can happen as this virus takes off in a densely populated areas with a weak health care system and difficulties in keeping the social distancing which can control the spread of the disease.

      We’re not safe from the development of new, more dangerous variants until pretty much the whole world is vaccinated and the progress of getting vaccines to poorer countries is moving much too slowly. The wealthy countries need to be thinking about the vast costs of the lockdowns we’ve required so far and spending a fraction of this amount on producing the vaccines for those countries less able to afford them. What helps them now, helps us in the future with less of a risk of expensive lockdowns.

  8. J Curwen says:

    There are max 10 ng of DNA in the so called mRNA vaccine per jab, which corresponds to 3,09 x 10^10 300bp fragments. Do we really want to risk genomic integration in experiments with children?

    1. x says:

      That’s cute.

  9. Marko says:

    “…an analysis of 63 million medical records by data scientists shows that while reinfection is possible, it is rare. Out of about 400,000 people with positive tests for the coronavirus, only 0.4 percent tested positive twice in a period more than 90 days apart, according to the study by health-care software company Epic Systems.”

    Oh look, you can get meaningful reinfection data without genomics.

    1. Doug H MD says:

      so tell me again; why are we vaccinating those already recovered with 2 SHOTS?

    2. Doug H MD says:

      wrong link? or now dead

        1. Marko says:

          Correction: Wapo, not NYT.

  10. Marko says:

    The denialists were right. Covid-19 is just like a flu outbreak. Specifically, the 1918 flu outbreak:

  11. Blaine White, M.D. says:

    Since I commented on concerns about the adenovirus-vector-Spike vaccines, I note today (April 23) CNN reports a FDA panel approved resumption of use of the J&J adenovirus-vector-Spike vaccine against C19. However in those discussions, the number of reported U.S J&J Vaccine Induced Thrombotic Thrombocytopenia (VITT) cases increased to 15 with 12 being cerebral venous thrombosis. Also the vote to resume use of J&J was not unanimous – 10 for, 4 against, and 1 abstain. The decision also included addition of label warning and instruction against use in women under 50. I doubt we’ve heard the last of occasionally serious platelet activation problems with these vaccines.

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