Vaccines Reduce Overall Risk By 1%, not 95%

A peer-reviewed study in the Lancet shows that the Absolute Risk Reduction for those receiving the Pfizer, Moderna, Johnson & Johnson, or Astra Zeneca COVID-19 vaccine is a paltry 1%, not the commonly-cited 95% that is advertised.

One again, so-called “experts” have played fast and loose with statistics.

The trick is the reporting of Relative Risk Reduction versus Absolute Risk Reduction. According to the study, Relative Risk Reduction (RRR) is calculated using those in a population who are at significant risk from infection and sickness either receiving or not receiving a vaccine, but Absolute Risk Reduction (ARR) uses the entire population:

Vaccine efficacy is generally reported as a relative risk reduction (RRR). It uses the relative risk (RR)—ie, the ratio of attack rates with and without a vaccine—which is expressed as 1–RR. Ranking by reported efficacy gives relative risk reductions of 95% for the Pfizer–BioNTech, 94% for the Moderna–NIH, 90% for the Gamaleya, 67% for the J&J, and 67% for the AstraZeneca–Oxford vaccines. However, RRR should be seen against the background risk of being infected and becoming ill with COVID-19, which varies between populations and over time. Although the RRR considers only participants who could benefit from the vaccine, the absolute risk reduction (ARR), which is the difference between attack rates with and without a vaccine, considers the whole population. ARRs tend to be ignored because they give a much less impressive effect size than RRRs: 1·3% for the AstraZeneca–Oxford, 1·2% for the Moderna–NIH, 1·2% for the J&J, 0·93% for the Gamaleya, and 0·84% for the Pfizer–BioNTech vaccines.

In other words, because the risk to the young and healthy from COVID-19 is so incredibly low to begin with, administering a COVID-19 vaccine to them has almost no effect on their risk. For example, a person who has a 1% chance of serious COVID-19 who takes a vaccine with 95% relative risk reduction ends up with a 0.95% reduction in their absolute risk. The higher the initial risk for a person, the more promising the risk reduction from being vaccinated becomes, but populations who bear little to no risk from COVID-19 gain almost nothing from taking a COVID-19 vaccine.

The study indicates that the mass efforts to vaccinate will reduce overall, absolute risk to the population by around 1% versus not vaccinating at all. Considering vaccines protect the vaccinated person (not the rest of the population), and the vaccines are still experimental (not FDA approved) and may yet be found to cause more serious side effects, this might be a deal-breaker for those in low-risk demographics.