Dr. Lickerman on the Moderna vaccine

December 22, 2020 • 10:30 am

My GP has written another post on vaccines, this time on the new Moderna vaccine, which has just been approved by the FDA.  Click on the screenshot to read it, or you’ll likely be satisfied with the conclusions and unanswered questions below, which were remarkably similar to his take on the Pfizer vaccine.

That’s because, except for a difference in storage conditions (the Moderna vaccine requires far less cold than does the Pfizer one), the trials show both are about equally effective (94.1% for Pfizer, 95% for Moderna, which are probably not statistically significant. Both are also mRNA vaccines that inject the code for making part of the virus’s spike protein into the body, where part of the protein is made, activating antiviral antibodies, and then the mRNA is degraded. (See below for an article about how these vaccines work.) There’s a slightly higher incidents of side effects with the Moderna vaccine as well: muscle pain and joint pain after the jabs are about 20% higher for Moderna’s vaccine (an incidence of around 40%) than for Pfizer’s (incidence about 20%). But these aren’t severe side effects.

The Pfizer vaccine was tested on individuals older than 16, while Moderna’s on individuals older than 18, so efficacy in that two-year age range remains an unanswered question for Moderna.

Finally, the two doses of Moderna’s vaccine were spaced 28 days apart rather than Pfizer’s 21, but this may not be important since there seems to be a leeway of a few days. Consult your doctor.

The overall take (these quoted from the post):

  1. The vaccine is highly effective in preventing symptomatic COVID-19 infection.
  2. The vaccine is safe. Adverse reactions, both local and systemic, are mostly minor. Though the study hasn’t yet gone on long enough to prove there are no serious long-term adverse affects, such adverse affects, if they exist, are likely to be rare and non-life-threatening based on other Phase I and II studies of other RNA vaccines.
  3. We recommend everyone who is eligible to receive the vaccine should receive it when it becomes available to them.
  4. It very well may take all of 2021 to get everyone who’s willing to be vaccinated to receive the shots, which means it likely won’t be until early 2022 that life returns to pre-pandemic normal. In the meantime, continue to wear a mask when indoors with anyone you don’t live with, wash your hands frequently, and refrain from dining indoors at restaurants.

And the unanswered questions:

  1. While suggested by the study, still left unproven is whether BNT162b2 prevents severe COVID-19 infection, whether it prevents COVID-19 infection after just one dose, and whether it prevents COVID-19 infection in subjects who’ve already had COVID-19.
  2. The study didn’t look to see if the vaccine prevents asymptomatic infection. Nor did it assess whether subjects who developed COVID-19 despite vaccination are less likely to transmit the virus. Thus, it’s not yet clear how effective the vaccine will be in containing the spread of the infection.
  3. The study hasn’t gone on long enough to tell if subjects who were vaccinated yet still contracted COVID-19 have a lower risk of long-term effects of COVID-19.
  4. We don’t yet know if the vaccine reduces the risk of dying from COVID-19.
  5. There was insufficient data to draw conclusions about safety and efficacy of the vaccine in children younger than 18, pregnant or lactating women, and patients who are immunocompromised.
  6. We don’t yet know how long immunity lasts and whether or not booster shots will be necessary.

As far as which one you should take, I think Alex’s recommendation would be to take whichever one is offered to you. The news last night said that big pharmacies like CVS may well stock both types, in which case you should consult your doctor.

Here’s a new NYT article by Jonathan Corum and Carl Zimmer about how Moderna’s vaccine works (click on the screenshot; I think the article is free for all). It’s a comic-book-like series of graphics which are very good, and I’ve put a summary at the bottom.

You’ll have to click on the screenshot below, perhaps twice, if you want the whole story in one place.

27 thoughts on “Dr. Lickerman on the Moderna vaccine

  1. Now that the second vaccine has been shipped, hopefully we will see things pick up. Out here in the middle of nowhere Kansas it seems a bit slow. To my knowledge they still have not done the assisted living facility that my mother-in-law is in. They are suppose to be high on the priority list after health workers.

    1. I suspect that the complicated logistics (and each state having its own plans for distribution) will cause some variability in who gets doses when. For example, one of my sibs (>65 yo) is a clinician at a major university center in a big city. He’s already received his first dose, although he’s far from the front lines of seeing/treating Covid-19, and I’d hope that those at the front, including paramedics, etc., would have had priority over him. (OTOH, given the underlying problems of his patients, they’d have major difficulties if infected.) Another sib (>65 yo), in a big city in a different state, only sees nursing home patients, including many with Covid-19. She won’t get her first dose until next week. I don’t know if that’s before or after the patients.

      1. I suspect that the complicated logistics (and each state having its own plans for distribution) will cause some variability in who gets doses when.

        That’s a recipe for a “post code lottery” – where people in neighbouring houses get different treatments, depending on which side of an administrative line one sits.

  2. My best guess is that you are more likely to see the Modern vaccine at your local pharmacy, since those locations are unlikely to have the -80 freezers needed for the Pfizer product but likely do have a standard -20 freezer. Once the AZ vaccine is approved (currently pending approval) its 4C storage (standard fridge) gives it a huge distribution advantage. But it’s a completely different technology (modified chimp adenovirus) so I’d be interested to hear your GPs take on the best option then.

    I was wondering whether the two RNA vaccines, which really only vary by a couple of amino acids in the sequence they transfer, are mutually compatible, in the sense of getting a first dose of one and a second of the other. Study obviously not done, but I’d be surprised if it really affected the outcome.

    1. My understanding from some while back was that the Moderna vaccine is RNA corresponding to just part of the Spike protein while Pfizer’s is to the whole Spike protein. At the same time as I’ve been trying to find out which part, I haven’t seen that lately. However, Moderna’s spike has two amino acid substitutions to proline residues. This piece in Chemical & Engineering News written for the semi-layman may help you understand the basis for those substitutions.

      Since I’m able to tick boxes for both Protein Chemist and Structural Biologist, I guess I’d prefer to get Moderna’s because it capitalized on one of the tenets of protein structure – that proline residues restrict the conformational possibilities of the protein chain wherever they occur. Also, a bacteriophage virologist colleague got his Moderna shots a couple months ago by being part of the trials. (I wasn’t selected because of being at insufficient risk of getting infected.)

      OTOH, for other reasons I wouldn’t object if it developed that it was Pfizer or nothing for me. But my protein background aside, I’d like to get either of the RNA vaccines over the more traditional protein-based vaccines since as I understand it, adjuvants are not required. Also, no adenovirus vector, since some of the antibody response can be superfluously directed to the vector.

  3. Some questions off the top of my head.
    Does the vaccine have an affinity for any particular type of cell (or vice versa), or simply for any cell it runs into after finding its way from muscle tissue to vascular or lymphatic system?
    Is the vaccinated cell specifically targeted by the immune system due to the foreign proteins it presents on its surface? Or does it just live out its lifespan before releasing further viral proteins/fragments?

    1. Depending on your background, there is a decent review at


      It’s a couple of years old, so addressing the technology in general, not this specific application but covers more than I needed to know (as a non-immunologist). To address your question the aim is to get the nanoparticles picked up by dendritic cells of the innate immune system where the proteins will be expressed and presented on the cell surface to the adaptive immune system to elicit an immune response.

    1. As I understand it, the boxes of the vaccine have temperature monitors that keep a running record of the temperature. New Mexico had to discard a box of Pfizer vaccine when the monitor showed that the temperature had not stayed cold enough. It may have been a faulty monitor, but they could not take a chance.

        1. Something tells me that the vaccine temperature monitors are attended with much greater attention than your local supermarket gives to the sell-by dates of their cans of grape seed oil.

          1. Sure but if all other things are equal, the one that’s safer is the one that has lower temperature requirements. It should be noted that a vaccine that must be kept really cold is also vulnerable to heat before it is packaged and the temperature monitoring device attached. In short, it is likely more difficult to produce and easier to screw up.

            1. Safety isn’t the concern here. Availability is. One vaccine will be more available because it has fewer requirements for storage. Both are safe. The safest one for you to get is the one that becomes available to you soonest.

              1. Clearly that’s true but obviously I was talking about all things being equal. At this point, I have no idea when I will be offered a vaccination and which vaccine it will be. If you are going to start getting into hypotheticals then I don’t really get why you are arguing with me.

              2. I guess I’m arguing because I think concerns about the Pfizer vaccine being less safe/effective because it has stricter storage requirements are misplaced. If malfeasance/incompetence/whatever are factors to fret over then surely these mitigate against most any treatments. Seems to me that it is reasonable to trust the protocols that have been established for both of these vaccines with equal confidence.

              3. Well, if you are worried that I won’t take the vaccine, don’t. I will gladly. Actually, I’ve had COVID already. Luckily it hit me less than the typical flu episode. Caught it from my wife who caught it from traveling to take a license exam. (Bad choice, IMHO) My concern for the vaccine storage issue was purely cynical and intellectual. I wouldn’t repeat it in front of anyone I thought was vaccine shy.

              4. He provided more entertainment than his rock-and-roll namesake though. Our host needs to let one through the security fence once in a while just for fun.

  4. “We don’t yet know if the vaccine reduces the risk of dying from COVID-19”

    As I mentioned in the comments on the last vaccine report, this can’t be right. If it is 95% effective, it is reducing the risk of death.

    Probably what he means is that we don’t know if it reduces the risk of death if you catch the disease after vaccination. If the vaccination is neutral with respect to disease severity once the disease is caught, the data implies that the vaccine reduces the risk of death by 95%. This is vastly different than the quote from the doctor.

    1. With at least the Pfizer and I think also Moderna, none of those who got the vaccine and then tested positive came down with a severe case, meaning hospitalization required. If the leap can’t be made from that re. dying…

  5. Odds on there will be a “discovery” that people with a history of severe allergic responses to [whatever] will also have allergic responses to this as well – same as with the Pfizer one. And for the same reason – most drug safety trials exclude people with histories of severe allergic responses to [whatever] because they are likely to have, uh, a severe allergic response during the trial.

    1. OTOH, as I think I’ve noted here before, I was excluded from the Moderna trial because I was deemed at insufficient risk of getting infected because of living with just one other person, not working among people etc, while a colleague who has 3kids and a wife, and who also works around a lot more people than I do was picked. He got the vaccine and not the placebo, too, so he’s a happy camper.

      1. In theory, the randomised controlled trial is the best (most statistically powerful, most accurate data for fewest people at risk and shortest-by-time) trial. Unfortunately, a truly randomised controlled trial would also put a certain portion of the population (people with stronger-than normal allergic responses, in this case; pregnant women (I don’t keep up on obs & gynae – has an male-to-female transgender carried a foetus to term yet? It is only a matter of time, and medical technology.); the foetuses they carry; people with major transplants and big medication loads …) at predictably higher risk than the general population, so …
        Well, you try getting a study past the Ethics Committee which doesn’t exclude such groups. My statistics prof would allow you to get away with a line mentioning such exclusions in a study design question, but that was teaching, not reality.

        I recently bumped into the medical “ha ha but serious” Twitter account “@justsaysinmice” (I suspect it appears in other corners of the Internet too). It needs a sibling account “@justsaysintheory”.

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