COVID Transmissions for 6-28-2021

Mixing vaccine types to fight Delta (important if you've had J&J)

Jun 28, 2021

Greetings from an undisclosed location in my apartment. Welcome to COVID Transmissions.

It has been 588 days since the first documented human case of COVID-19. In 588, the Franks and Burgundians invaded Northern Italy and lost horribly against the Lombards, who also converted to Catholicism that year; please note here that correlation is not causation.

Today I discuss the issues of single-dose vaccination vs the Delta (B.1.617.2) variant, specifically with regard to the Johnson and Johnson vaccine, but I also discuss more generally the concept of mixing vaccination technologies.

Then, some reader comments.

Bolded terms are linked to the running newsletter glossary.

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Now, let’s talk COVID.

Delta Blues: Boosting Johnson and Johnson

In past issues, I have covered how the “Delta” (B.1.617.2) lineage of SARS-CoV-2 appears to evade the immunity that is induced by receiving a single dose of the Pfizer or AstraZeneca vaccines. For reference, that is found here: https://covidtransmissions.substack.com/p/covid-transmissions-for-6-7-2021

The original data on this are from England, and do not include any information about the Johnson and Johnson or Moderna vaccines.

The Moderna vaccine I—and most others—consider functionally equivalent to the Pfizer vaccine. I would expect it to behave like that vaccine for the purposes of this variant. However, it is administered in a two-dose course, so I believe that completing a full course of that vaccine is highly protective against the Delta variant just as completing a full course of the Pfizer vaccine remains.

The Johnson and Johnson vaccine is a different story. It is a chimeric viral vector vaccine, so is similar to the AstraZeneca product. However, it is a single-dose vaccine, so it is unclear if it will be compromised by the Delta variant. There is supposedly a two-dose Phase 3 trial of the Johnson and Johnson vaccine going on, but I really had expected to get data from that trial already and haven’t heard a peep. I’m not sure what happened there.

Whatever it is that happened, we don’t know if two doses of the Johnson and Johnson vaccine are worthwhile, and we also don’t know if one dose alone is still protective against the Delta variant. In light of that, there are experts who are suggesting that people who got the Johnson and Johnson vaccine should receive a booster with one of the other vaccines to “complete” their course. You can read more about this here: https://slate.com/news-and-politics/2021/06/booster-shots-johnson-and-johnson-vaccine.html

I cannot give specific medical advice, so like many other non-physician experts, my advice to you if you have received the Johnson and Johnson vaccine is that you should talk to your doctor about options for supplementing your immunity. Maybe discuss with them the article that I just linked.

All of this, of course, is a microcosm of a bigger conversation about whether it is a good idea or not to give a prime-boost dosing schedule that uses different types of vaccines. Right now in the US, that is not the recommended label information on any of the vaccines. However, there are countries where it has been attempted, and it appears to be a successful strategy. Take this story, for example, from back in May: https://www.nature.com/articles/d41586-021-01359-3

In my opinion, the place where these mixed-dose approaches are most likely to work well are in circumstances where one of the doses is a viral vector vaccine. One of the big problems with viral vector vaccines is that the vector itself also generates an immune response, and that response can undercut the response to what you actually want to be immune to—SARS-CoV-2. This seems to happen even more when you give two doses, and gets in the way of good immunity. So, in my opinion, I think it’s likely that we’d see good results from clinical trials show mixed-dose schedules with prime-boost being done with a combination of an mRNA vaccine and a viral vector vaccine (I don’t think which is first will matter). I think that this approach could actually yield better results than doing 2 doses of a viral vector vaccine. This is speculation, though! Nobody knows the answer right now. Don’t make medical decisions based on anything in this paragraph; talk to your doctor and stay safe.

What am I doing to cope with the pandemic? This:

Exercise!

Yesterday, I thought it would be fun to try out my new bike and also go for my usual Sunday 3-mile run.

Yesterday was very hot, and this was a lot of stuff to do. I wouldn’t repeat the experience necessarily, but it was probably good for me.

Stay cool everybody! Lots of places are experiencing heat waves right now.

Reader Sam continued our conversation about myocarditis and vaccines in young children:

The ACIP clearly made the right call here. Still, as I've mentioned before, I worry about what this means for vaccination of children under 12.
Young kids need to be vaccinated, too. Toddlers -- the population with which I'm most concerned because, well, I have one -- are hospitalized in roughly one in 200 cases and suffer MIS-C in perhaps one in 2,000. And they develop long COVID -- it's hard to say just how often, but also hard to regard any number as trivial. This is to say nothing of the importance of vaccinating this population to control community spread, especially with things reopening and more infectious variants becoming dominant.
Yet, I have to think that the prospect of vaccine-induced myocarditis in such young children might throw a wrench into the works when it comes to extending EUA coverage to them. This would seem to lend some urgency to determining what exactly is causing this side effect, its likelihood of occurring different populations, and whether there's a way it might be prevented (e.g., timing of doses).

My thoughts:

We're just not going to be able to know until we see the vaccines deployed in children in that age group. I think, though, that the risk of myocarditis due to COVID-19 will still continue to outweigh the risk of myocarditis due to the vaccines, in any age group (see Carl's comment on this). So I'm hopeful that the risk-benefit will continue to be favorable.
Also, I think it might be mitigated by the lower dosages planned for young children. It's really hard to say. I hope that it doesn't mess up availability for that age group. Kids do need to be protected, you're right about that 100%.

In that, I referenced a comment from Carl Fink that I think made a really good point about myocarditis. Here’s that:

Dr. Walensky also wrote that COVID-19 is a much more significant cause of myocarditis than any of the vaccines, according to current evidence. So ... to prevent myocarditis, get vaccinated!

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.

Join the conversation, and what you say will impact what I talk about in the next issue.

Also, let me know any other thoughts you might have about the newsletter. I’d like to make sure you’re getting what you want out of this.

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