0.03% chance: Getting coronavirus after being vaccinated.

[Ms. Toad]

25. The manner of calculation is misleading

The vaccine effectiveness (95%) was arrived at by comparing # of cases of COVID 19 among vaccinated individuals to # of cases among unvaccinated (in the same population, at the same time). In other words it is comparing a control group of similarly sitauated unvaccinated people to the vaccinated group all experiencing the same exposures over the same period of time. Under those circumstances, out of every 100 unvaccinated people who came down with COVID, only 5 vaccinated people did.

What 95% represents is your decreased likelihood of getting the disease when exposed to the same circumstances as someone who was unvaccinated.

The figure in this article is an isolated calculation comparing absolute numbers (not in comparison to a control group) over a period of time that varies by individual, arrived at during a period when mitigation measures were in place.

To make the point - the Pfizer trial numbers suggest being unvaccinated is remarkably effective! Only 162/22,000 unvaccinated people got COVID) - that's a .7% chance of getting infected!!!.

But if that is accurate - if each person only has a .7% chance of getting infected - how did we get to 10.3% of the US population (33,863,409/328,200,000) having been infected with COVID? If my "chance of getting COVID is .7%, there should only have been 2,297,400 cases - ever - in the US. There were 14 times as many a predicted! How can that be???

The explanation: "There are three kinds of lies: lies, damned lies, and statistics."

The explanation is that whoever wrote that you had a .03% chance of gettign vaccinated didn't understand the statistics (The article is behind a paywall, so I don't know whether that description was part of the article or not). .03% isn't measuring your chances of getting COVID, as a vaccinated person. It is a measure of the portion of the population at a particular point in time, under the circumstances that existed at that time, with varying vaccination duration, who were actually infected during that time period. Without more data (comparing vaccinated to unvaccinated, adjusting for those vaccinated a month v. those vaccinated for 3 months (and exposed to far more COVID-causing events), adjusting for mitigation measures in place) it says very little about your chances of getting COVID.

That is not to say the vaccinations are not remarkably effective. BUT it is misleading to say you have a .03% chance of getting COVID. More accurately, the number itself would be adjusted for the varying periods of time people were vaccinated (and subsequently exposed) and the infection rate in the communities in which they lived and worked, and what mitigation efforts were in place (and likely other factors I am not thingking of).

And AFTER adjustment it would be described more like this: You have a .XX% chance of becoming infected with COVID over an XX month period of time if you are vaccinated, and live in a community with an average 2-week infection rate of XXX/100,000 infection, in which the following mitigation efforts {XXX, XXX, XXX} are in place.

So - .03% chance of getting COVID is a statistical lie.