Intuitively getting vaccinated does not just protect you but protects those around you but proving this can be challenging with so many confounding factors.
This week Fred Goldstein and I look at the concept of Herd Immunity and especially at the local level, and in the case of an elegant paper looking at data out of Sweden at the family unit level. The study benefits form the fact that their national health system has data on basically everyone who lives in that country, leading to a cohort of just under 1.8 million people.
The results were convincing. Among families that have two people living together, having one of them be immunized reduced the rate of infection in the other person by 45%. Larger families showed increased response.
Like all papers is should be read with a critical eye and we discuss how to approach the data from this study and others and review some of the limitations from the study and what that means for the results
https://youtu.be/mj7C3oNPBpA
Raw Transcript
Nick van Terheyden
Hi, this is Dr. Nick on the incrementalist here with incremental insights for better business better health.
Fred Goldstein
And I’m Fred Goldstein, with accountable health here helping employers payers and other companies develop and improve their population health programs. So Nick, this week, everybody’s been talking about it, and particularly here in Florida, where Governor Sanders came out and said, Look, you could take the vaccine if you want, because it’s just for you. It doesn’t protect anybody else. But now there’s this study out called the association between risk of covid 19 infection in non immune individuals and COVID-19 immunity in their family members, that apparently says something different. So what’s in this study?
Nick van Terheyden
So first of all, I you know, what is, you know, you live in this state, I still can’t work out. And, you know, is that position there to give him a fallback as well, I did say you could get it, I just I don’t understand. I think intuitively, people with a sense of reality, and following of science would say, if I get the vaccine, yes, it benefits me. But there is some other important elements to this that, you know, is referenced, not fully understood, I think, in some cases, but we reference herd immunity, which has a specific definition. And if I get the vaccine, and you know, the people around me get the vaccine, and there’s somebody that doesn’t have it, we essentially are protecting. And the predominant purpose of this is to protect people that can’t get the vaccine. So there is a small number of folks who for a variety of immunological reasons, medical reasons, cannot take vaccines, and they desperately need for the rest of us. So intuitively, I think that just makes sense. I mean, if somebody wants to challenge us and say, No, it doesn’t, and here’s why. We’re happy to hear from you. But we want to hear with data with science, and backed up by papers that have been published, or at least on the pre published service. So if somebody wants to push back on that, that’s fine. But here’s this study that you mentioned. And it comes out of Sweden, and this is what’s really interesting. So it’s a cohort, wait for it. 1.8 million people because they’ve got a nationalized health system, what a glorious data set. And there are some problems with it. But essentially, they looked at this and said, if you’ve got immunized people, you know, the vaccination in families, and not everybody is vaccinated, do you see a difference in incidence of infections? And the answer to this is very clear. If you got people in your household, you are having a positive impact and reducing the rate of infection and the other people in the household by 45%. That’s an astounding number. We’d be grateful for that in any drug trial, or anything that we were doing. And when you get into llotja member family, each additional member that’s immunized, the rate of infection on the non immunized members drops dramatically. So it’s down to 97%. In a five member family, that’s fantastic news, because essentially, I’m sorry, but your governor is wrong. This is not just about you.
Fred Goldstein
Oh, my gosh, it’s very true. I did, I did read the study, I thought was fantastic. Because it’s just naturally obvious. This thing is a respiratory virus, you know, it gets out in the air, you have it, you’re gonna spread it. If you’re vaccinated don’t have it, you’re less likely to spread it because you don’t have it. You know, so it just it just didn’t make any sense to say that this was one sided. A couple of things with the study that that I thought were interesting. I think they had a comparison group that would include two individuals who were non vaccinated in a household. And the average age for those I believe I recall, right? We’re in the 20s, or something like that, or maybe a little higher than that. But they were much lower age than the people who were vaccinated that they then had in the families. So I’m wondering if there’s some behavior change, maybe some individuals in that group were not quite as interested in the vaccine and doing more stuff out there not you know, using not using masks as well. And also in the households. If you think about it, if you’ve got a household, the more people you end up in there having vaccinated shows you’re clearly interested in doing the right thing. So are there some potential other confounders that might reduce the number somewhat but obviously not to a large extent?
Nick van Terheyden
I think that’s right. And I think that’s the important point is to look at all of this data with a critical eye. You know, people put out for the most part with good intentions. Even I forget which paper was retracted that was, you know, 8x wrong or, you know, a significant number. And I don’t think there was any mal intent. I mean, for the most part, that’s the case. But we, you know, we don’t see what we don’t see. And it takes that’s part of the peer review process that sort of looks at this, and not everybody can see it, because we’re all sort of focusing and you know, it’s hard to get out of your own bubble. And you raise an important point on this, because that actually talks to the area that I think is also not covered or, you know, confounds the results a little is how do you assess they don’t talk about how you assess people that are non immunized? And you know, based on that, could they have had asymptomatic infections, you just didn’t know it? So actually, they’re resistant and don’t you don’t see any cases or the cases that occurred didn’t see it? They did do some sensitivity analysis. And I’ve got to be honest, My specialty is not statistical detailed analysis. I do know people that are good at this, but their sensitivity analysis, looked at immunization via vaccination alone and found similar results. So I think it’s reassuring overall, but you know, that’s exactly right. You look at these things with a critical eye and in some cases, critical eyes, there’s no, this doesn’t work. Oh, by the way, it’s right. It’s biocity is what you’re looking for,
Fred Goldstein
by a VR city. That’s what I need that term. So I think it’s great because this, the numbers were so large, that even some of that influence I talked about would not be enough to impact those numbers one way or the other, even even if they weren’t considered. And I think it’s important as people read these studies to read the limitations, typically, the authors will point out, these are the areas that might make this slightly different or greatly different or whatever, because we didn’t look at them. So once again, Nick, it’s been another fantastic week discussing what’s going on with COVID This is Fred Goldstein with the Campbell health if you’d like more information, please go to accountable health LLC, calm. Thank you so much.
Nick van Terheyden
And this is Dr. Nick. I’m the incrementalist here with incremental insights for better business, better health.
