The statistical secrets of the Covid-19 vaccine


This is an old question in the public health community-do all these numbers help people or overwhelm them. But more and more information about vaccines seems to ease the hesitation, rather than exacerbate the hesitation. It depends on how people view their risk profile. “If you own Covid, you will get 100% Covid, otherwise, you will get 0% Covid,” Olliaro said. “You must consider the opinions of individuals in the community.”

one of The hallmark of a pandemic is that it affects different people in different ways. In the United States, poor people and people of color are much more likely to get sick and die from Covid-19 than white people and rich people. Older people face greater risks than young people.

Like all other medical interventions, the vaccine itself has both risks and benefits.Johnson & Johnson and AstraZeneca vaccines are very rare but Severe blood clot, Leading to the suspension of the Johnson & Johnson vaccine in the United States last month. People with severe allergies may be more likely to get anaphylactic shock from two doses of mRNA-based vaccines.

All these complex situations have created a fog around the decision-making space, making risk-benefit calculations for some people more complicated, or for those who think they are at low risk of Covid-19, or who are more concerned about side effects than side effects. space. They need this and think it is okay not to be vaccinated. “Most people are not sitting there worrying about decimal numbers, but thinking:’I have to weigh the risk-return ratio,'” said Alexandra Freeman, executive director of the Winton Risk and Evidence Exchange. Cambridge University. However, just because most people are not doing math, it does not mean that they are not chewing on the problem. As Freeman said, “Risk is very subjective.”

Well, let’s talk about those blood clots. Freeman’s team put together a bunch of infographics, weaving some of these threads into useful tapestries.Instead of comparing the risk of getting Covid with the risk of vaccination (an apple to orange problem), they published a copy Documentation Compare the potential blood clot risk of the AstraZeneca vaccine with its actual benefits, and compare the number of intensive care units where the vaccine can prevent Covid. Then, they cut it into small squares based on age group and exposure risk. (In real life, the exposure risk varies from country to country, even from industry to industry… and the group assumes that the overall efficacy of the vaccine is 80%, which is a necessary simplification method… and they use fixed The time interval is 16 weeks, because all these risks will change over time as the infection rate rises and falls. Statistics!)

They estimate that among 100,000 low-risk populations, the AstraZeneca vaccine may cause blood clots in 1.1 individuals and only prevent 0.8 ICU admissions. If you are a person who just stays away, that seems to be the reason to avoid AstraZeneca vaccine-in fact, European regulators have restricted its use. Fortunately, there are all other vaccines.

At the other extreme, people who are at high risk of exposure for some reason (for example, many infections in the county are prevalent) among the 60 to 69 years of age, the vaccine may cause only 0.2 blood clots (it seems to mainly affect young people ), but left 127.7 people outside the ICU. It forms a stark case. In most of the Winton Center groupings, the risk of using the AstraZeneca vaccine has paid off.

Again, despite The United States and Europe delegate the power to evaluate these vaccines to the companies that make them. Everyone uses slightly different protocols and different populations. A multi-arm study of all these methods may eliminate these statistical problems.WHO actually Announce Such a trial took place in 2020; Nothing seems to happen.


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