Experts opinion series

Safety of vaccines: a question of understanding risks and statistics.


Оne of the interesting things about the current situation (aside from the marvelous use of different scientific strategies to develop vaccines, obviously, messenger RNA, vectors, many different viruses being used as vectors, and DNA plasmids, etc) is a real explosion of information about how to develop vaccines. But in addition the search for reactions to vaccines and the science of dealing with vaccine safety has also increased tremendously during the last couple of years. And rightly, because, of course, it's important that we know what, if any, reactions there are to vaccines. But there's an important point that in a way relates to what I said about teaching children about vaccines, and that is another point of education that is unfortunately lacking or, at least in most countries lacking, and that is teaching children about statistics and risk. Now, I suppose those people who bet on horses understand this because they spend their lives putting money down on what they think is a good risk, rather than a bad risk. But by and large, people do not really understand risk in terms of the statistics. That is, when you talk about a vaccine having 90% efficacy, and you talk about a vaccine causing a certain reaction one in a hundred thousand times, you know you're balancing statistics, you're balancing the efficacy of a vaccine against its ability to cause a reaction that you don't want. Now there is no such thing as absolute safety. You know, if you have a meal, a large meal, there is some finite chance that you're going to choke on the meal and have a severe reaction. Of course, that risk is very, very low. And similarly with vaccines: there is a risk, of course. But if the people understand that the risk is one in a hundred thousand compared to the risk of the disease, being, let's say, just for argument's sake, the risk of death being one in a thousand, any sane person would choose the vaccine. But the problem is that many people do not understand risk, and, again, perhaps, I'm putting too much emphasis on primary education, but again, I in the perfect world would insist that every child take a course in statistics, so that they understand risk. And I think that's a very important part of education not only for vaccines but for life in general.