With the news that COVID boosters are going to be recommended 8 months post infection, the immediate question is whether you should be lining up to get one.
There are other questions, of course, but for most of us, the real information that we want is about our action steps from here.
Let’s look a bit at how to frame your individual decision on boosters. It helps to think about a bit of a broader perspective on risk and on how the Delta variant may change that calculus.
How likely is a booster to prevent severe disease?
When approaching the decision about boosters, I am not just thinking about the risk of getting infected, I am thinking about the risk of getting really sick - that means being hospitalized, needing a ventilator, or dying.
If SARS-CoV-2 infection manifests as a cold, it’s just not a big deal.
But if that infection leads to getting much sicker, a super-contagious variant is a real concern.
And that concern extends beyond the immediate folks who are infected and the people that they directly infect - the downstream impact of an ICU overrun with COVID patients leads to worse care for anyone else who gets sick.
When the hospitals near you are full of patients with COVID, that means resources are strained and the care of people with heart attacks, strokes, and other infections can be impacted negatively (you know, the flattening the curve stuff).
So how well does a booster work here?
We have no freaking clue.
The data that are published on breakthrough infections in healthcare workers post vaccination paint a picture that’s very reassuring. It means that the breakthrough infections that we see in people who have been vaccinated generally aren’t leading to hospitalizations, ventilators, and death.
While it’s clear that you can become infected with COVID after vaccination - and that you can spread COVID if you’ve become infected - it doesn’t appear that you’re likely to get all that sick.
Who is getting really sick from COVID now?
You may have heard some of the warnings about the spike in cases from the Delta variant as “a pandemic of the unvaccinated.”
While that’s certainly true, it’s a bit incomplete.
It is absolutely the case that the vast majority of people who are getting really sick from COVID now are the unvaccinated. The ones who are filling up ICU beds are almost all unvaccinated. The normal vaccinated breakthrough cases usually aren’t that sick.
But another group that we need to worry about are folks who had a poor response to the vaccine.
The particular patients who seem to be at the highest risk are people post transplant who are on medications that suppress the immune system and prevent organ rejection.
You’d also be worried about anyone on chronic medications for autoimmune disease. Older patients may not have as good a vaccine response, although this is more difficult to quantify.
An anecdotally, hospitals are seeing enough infections in people on chronic medications that suppress the immune system - and tons of post-transplant severe infections - that a booster seems like a no-brainer for this group.
The studies suggesting the benefit of a booster don’t look at the outcomes we care about
The reason you haven’t seen the report of a high quality clinical trial about the impact of boosters on severe disease and disease spread is because this trial hasn’t been done.
I know that I’ve droned on and on about the importance of having high quality research to support your medical decision making. That’s partly because of how much I value it in my own clinical decision making, but it’s also partly because I see a dearth of it in the media representations of how to approach medicine.
Unfortunately, waiting until we can conduct the actual research before making decisions is boring, time consuming, and expensive. It’s much easier to just extrapolate based on preliminary data to come up with a plan - and since we don’t have data, you’re seeing a lot of extrapolation.
The extrapolation is highly reasoned, deeply considered, and well intentioned, but it is still extrapolation.
What’s the argument for why to give boosters to everyone?
This is easy - breakthrough infection is clearly a possibility, those who have had a breakthrough infection can spread the virus, antibody levels seem to wane after about 8 months, and giving boosters raises antibody levels. And it’s not clear that giving boosters limits doses that would otherwise go to people getting their initial inoculation.
When you think about that logical chain of events, it seems obvious to give boosters.
So what’s the argument against it?
This is easy too - we just don’t know if it makes any difference. We don’t know how big the effect size is.
And then there’s the suggestion that the reason why you can get breakthrough infections is that the virus enters the body through your respiratory tract, where the current vaccines don’t stimulate that great of an immune response. According to this theory, unless a vaccine does a better job of inducing mucosal antibody production, we’re still going to see breakthrough infections regardless of the blood antibody levels that can be achieved with a booster.
Take a look at this Twitter thread from a coronavirus expert hypothesizing that maybe we should be developing and testing intranasal vaccines rather than just giving more shots:
What’s the bottom line?
For you, the person reading this newsletter, there’s basically no downside to getting a booster.
The same risks apply to a booster as apply to the initial doses - they rev up your immune system and so there is a possibility of causing symptoms related to activation of your immune system.
The extremely small chance of a severe adverse reaction - like inflammation of the heart (myocarditis) - is there, but the absolute risk is tiny.
But to think that a booster - if you aren’t on medications that inhibit your immune system - will have any real benefit for you or your family just isn’t clear from the data.
There are truly vulnerable people who would benefit from boosters, and getting transplant recipients and people on chronic immune-suppressing medication their boosters makes total sense. There’s also a question of whether the elderly (and what age defines someone as “elderly”) should get them too.
The other thing that I wonder about is the downstream impact on the vaccine-curious or the unvaccinated. If the suggestions of more shots means that fewer people get their initial doses, what does that do for uncontrolled viral spread? What additional mutation risk exists?
We don’t know the answer to that, which is part of my point in the first place.
So you should certainly feel free to get your booster if you want one. I don’t see any major downside.
But I increasingly wonder whether boosters may simply lead to an increasingly scared minority who are hyperimmune to COVID without having a significant impact on the overall trajectory of the pandemic.
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