They published the following a month after https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497/ ... It

They published the following a month after https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497/ ... It is customary yet inappropriate to compare vaccine efficacies and make policy decisions solely on relative risk reduction (RRR) from clinical trials with different protocols in populations with different background risks for COVID-19—unless vaccines were tested within a common trial as advocated by WHO.[3](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497//#bib3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497//#bib3) RRR focusses on those who benefit from the vaccine and, although more stable across event rates (levels of risk for COVID-19), its interpretation requires knowing the actual background risk and its variability. Absolute risk reduction (ARR) considers all individuals and translates conveniently into number needed to vaccinate within a population with a given risk,[3](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497//#bib3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121497//#bib3) but its public health significance varies with the risk. For any given RRR, ARR is higher when event rates are higher—eg, earlier into a vaccination programme, or in high-risk groups—and decreases as risks decline. Both ARR and RRR are helpful to assess trade-offs between benefits and harm, because evidence is still limited on whether or how they change across the range of individual responses and risks related to age, comorbidities, behaviours, and level of exposure, as well as over time—with risk of COVID-19 decreasing with vaccination scale-up or altering due to virus variants. ...