Yes, I am vaccinated with J&J. And it works better than you think

So, more than a month after the J&J vaccine EUA, I finally got unblinded this week.  Instead of that fancy little CDC vaccination card like everybody else, all I’ve got is this letter from the research sub-contractor to show for it :-).  As I strongly suspected based on my significant side effects, yes, I did get the actual vaccine back in September.  Interestingly, the medical assistant who unblinded me told me that, in his experience, everyone who had thought they actually had the vaccine based on side effects really had.  

With my unblinding this week and my firstborn getting the J&J courtesy of NC State on the same day, I’ve really been thinking about relative efficacy.  Among other things, I kept thinking about this chart:

After about day 31-32, infections in the treatment arm drop off a cliff while there’s still robust increase in the placebo arm up through day 53 or so (pretty curious as to this dramatic drop-off then).  In short, as has been reported, the efficacy of J&J continues to increase fairly dramatically even after the official 28-day endpoint (and, you really do need to stick to a pre-registered endpoint to prevent statistical shenanigans of the “oh, the data on day 34 is really good!” variety).  

Anyway, this got me to thinking, hey, now, maybe the biggest difference between Pfizer and Moderna is that we don’t measure efficacy till 35 and 42 days after the first shot (two weeks after 2nd dose). 

So, not only did I bounce this idea off of BB, but an actual virus expert, NCSU professor Matt Koci.  Nothing to further my hubris as an amateur epidemiologist like bouncing an idea off an actual one and seeing that my intuition about the timing was important.  Really good vaccine Q&A here with Matt (and my friend Matt Shipman asking the questions) and I’ve highlighted the key part:

1) Which one is better at protecting me from death?

All three vaccines being used in the U.S. (as of April 2021) are 100% effective at preventing death from COVID-19.

2) Which one is better at keeping me out of the hospital?

Again, all the vaccines currently being used are 100% effective at keeping you out of the hospital from COVID-19. [Note: in the Moderna trial one person in the vaccine group was hospitalized, but they weren’t confirmed to have COVID-19 positive.]

3) Which one is better at preventing mild to moderate symptoms?

Again, believe it or not, they are all about the same here. When the Johnson & Johnson vaccine was first announced, the media made a lot of noise about how the two mRNA vaccines had 94-95% effectiveness and J&J was 72% effective at preventing mild to moderate disease. But as we’ve continued to follow people who’ve gotten the J&J vaccine we’re learning that the level of protection goes up with time, and maybe we weren’t comparing apples to apples.

TA: Time out — can you explain that last part for me a little more?

Koci: For all the vaccine trials, the companies focused on assessing effectiveness starting two weeks after the last shot. The J&J is just one shot, so the clock starts two weeks after that shot. However, the clock doesn’t start for the mRNA vaccines (Moderna and Pfizer) until two weeks after the second shot. That’s 5-6 weeks after you received your first mRNA shot. If you line up the comparisons based on the first shot instead of the last shot the J&J vaccine looks to be about as effective as the mRNA vaccines.

Maybe the immunity will not last as long without the booster.  Maybe.  But for now, if you can get yourself a shot and its J&J you should definitely, happily do so.  (Alas, just as I was finishing this post, news about them falling way short on their production).  

About Steve Greene
Professor of Political Science at NC State

2 Responses to Yes, I am vaccinated with J&J. And it works better than you think

  1. itchy says:

    Over the last year, I’ve bombarded my microbiologist wife with pandemic-related questions. On this subject, she has been consistent. In her opinion, all the main vaccines — Pfizer, Moderna, J&J — and probably Oxford/AstraZeneca and Novavax, which hasn’t yet applied — are similar in their efficacies.

    The differences are in how and when and where the trials were set up, and the dosages and regimens, but once you normalize for those, the end result is that they’re all effective.

    • Steve Greene says:

      And that seems to make intuitive sense (which, to be fair, can mislead us). Doesn’t really matter all that much just how your body meets this spike protein, but when it does, your immune system learns what to do and prepares.

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