COVID Transmissions for 10-25-2021
Hard vaccine efficacy data on Pfizer boosters; also another pregnancy study
Greetings from an undisclosed location in my apartment. Welcome to COVID Transmissions.
It has been 708 days since the first documented human case of COVID-19. In 708 (very approximately), tea drinking began to rise to popularity in China. I’d bet even then there was someone who thought it would be a temporary fad.
Today we’ll discuss real, hard efficacy data on boosting Pfizer’s vaccine—something I’ve wanted to have for awhile. I also link a brief communication—at Letter to the Editor, in fact—commenting on the use of COVID-19 vaccines in first trimester pregnancy.
Have a great week!
Bolded terms are linked to the running newsletter glossary.
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Now, let’s talk COVID.
Pfizer and BioNTech complete Phase 3 trial of third dose
You may have noticed my concern over the fact that third mRNA vaccine doses—additional boosters—are being approved and recommended with only antibody-based data available.
Thankfully, that data gap is closing. Pfizer and BioNTech recently announced completion of a Phase 3 trial that compared the standard 2-dose regimen to a 3-dose regimen (one with the additional booster dose): https://www.businesswire.com/news/home/20211021005491/en/Pfizer-and-BioNTech-Announce-Phase-3-Trial-Data-Showing-High-Efficacy-of-a-Booster-Dose-of-Their-COVID-19-Vaccine
This study looked at efficacy against disease in about 10,000 patients ages 16 and older. This came out at 95.6% relative vaccine efficacy. Remember that the 2-dose regimen is already more effective than placebo, so because this number is 95.6% relative to 2 doses, it represents a further reduction in risk on top of the protection that the 2-dose regimen provides. The 3-dose regimen appears to be very helpful in preventing COVID-19.
Importantly, these data were collected during a period when the Delta variant was common in circulation in the study geography. So we are not playing a guessing game when it comes to the impact of this third dose on the circulating pathogen as we know it today. The data are current and tell us that this approach works.
There is still a conversation to be had, however, about whether the 2-dose regimen offers good enough protection already, and whether in light of that we should consider focusing on vaccinating more new patients rather than boosting existing ones. I would suggest that we should just make a lot more vaccine and distribute a lot more vaccine—everywhere, for everyone. That would make that conversation moot. There are ways we could do that. The political will just has to move in that direction.
Norwegian study suggests no impact of first-trimester COVID-19 vaccination on pregnancy loss
This is a study of about 20,000 women,1 showing that vaccinated patients are not at elevated risk of miscarriage: https://www.nejm.org/doi/full/10.1056/NEJMc2114466
In fact, if I read this Letter to the Editor correctly, it almost appears that those who were vaccinated in the previous 5 weeks had a marginally lower rate of miscarriage than those who were not. Since the authors do not make this conclusion I assume the statistics don’t bear it out, but it wouldn’t surprise me if it were true—COVID-19 can lead to adverse pregnancy outcomes, so preventing it is something I’d guess is overall good for avoiding those outcomes.
It is legitimate for pregnant people to be concerned about the potential impact of any medical treatment on their pregnancy as well as their personal health. This is why such studies are being performed. What is not legitimate is that anti-vaccination sources have attempted to manipulate these fears with unfounded claims about impacts on both pregnancy and fertility; these began before there were any real data available in pregnant people, but have taken root and had an outsize impact on vaccine uptake in that population.
Now we are in a place where several studies have provided real data, however. So far, the news is all very good for the safety of COVID-19 vaccination during pregnancy, which we can contrast with our knowledge that COVID-19 is not something you want to get while pregnant.
I do find it regrettable that the study did not comment on the safety profile for its subjects, but I do not know if the authors had such data available to them. Health during pregnancy is not all about the fetus, though it seems sometimes this fact is overlooked in the medical literature.
What am I doing to cope with the pandemic? This:
Watching: His Dark Materials
HBO has made an adaptation of Philip Pullman’s His Dark Materials book series, which is a modern classic.
There was a movie made about a decade ago, which…well, could have been better. Originally, it was supposed to be a trilogy of films, much as the books are a trilogy, but the two sequels were canceled after the film wasn’t a huge success in the US.
The TV adaptation is far and above better. We’ve really been enjoying it.
And no, I haven’t seen Dune yet, otherwise I’d be talking about it today instead. But I plan to! The whole thing needs to be planned around a newborn, of course.
Reader Noah, who is a healthcare provider with direct experience, commented the following regarding the question of intravenous injection possibly causing the rare myocarditis events seen sometimes with mRNA vaccines against COVID-19:
The hypothesis that inadvertent IV injection is related to adverse events seems odd to me. I was explicitly taught not to aspirate for IM injections in nursing school. I don't think it's a widespread practice anymore (though I believe it used to be) and I have never seen anyone aspirate for a IM injection. Before we jump to this conclusion I'd like to see some evidence about the actual likelihood of an inadvertent IV injection.
Noah is 100% right that more evidence than just a mouse study is needed. I don’t know exactly what that evidence needs to be, to be honest—I think this would be hard to study directly and ethically in humans, but there are people cleverer than I who might have ideas for how to do that.
That said, even if they could demonstrate that the hypothesis is correct, Noah’s comment makes me wonder—what actions could we take based on that knowledge? To change practice for the sake of an exceptionally rare event might have other negative impacts; I don’t know. My reply:
My understanding—and I’m stating this partly because I think you can correct me if I’m wrong—is that they stopped teaching people to aspirate because it is uncomfortable for the patient and the consequences of an inadvertent IV injection were thought to be low. I agree that inadvertent IV injection is probably rare; myocarditis with mRNA vaccination is also super rare. I honestly don’t know what the recommendation for practice would be if this hypothesis turns out somehow to be correct. Aspirate in certain demographically at-risk patients?
You might have some questions or comments! Send them in. As several folks have figured out, you can also email me if you have a comment that you don’t want to share with the whole group.
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No corrections since last issue.
See you all next time. And don’t forget to share the newsletter if you liked it.
Always,
JS
I prefer to use the term “pregnant people,” but the study says “women,” and in an effort not to mislead as to the patient population, I use the terminology that the study itself uses.