Why did Dagan manipulate 'vaccinated' status versus 'unvaccinated' the way it did, if ONLY to place lack of efficacy, harms, deaths etc. in UNVACCINATED bucket when they were infact 'VACCINATED'

days 14 through 20 after first dose of vaccine, days 21 through 27 after first dose (administration of second dose was scheduled to occur on day 21 after the first dose), day 7 after the second dose

https://www.nejm.org/doi/full/10.1056/nejmoa2101765?utm_source=substack&utm_medium=email

‘Covariate balance after matching was evaluated with the use of a plot of the mean differences between variable values (standardized for continuous variables) for the vaccinated and unvaccinated groups, with a difference of 0.1 or less considered to be acceptable.⁹ Survival curves for the vaccinated and unvaccinated groups were estimated with the Kaplan–Meier estimator.¹⁰ We considered three periods: days 14 through 20 after the first dose of vaccine, days 21 through 27 after the first dose (administration of the second dose was scheduled to occur on day 21 after the first dose), and day 7 after the second dose until the end of the follow-up. For each period, we used the Kaplan–Meier estimator with daily outcome and censoring events to compute the probability (“risk”) of the outcome during the period, using matched pairs in which both persons were still at risk at the beginning of the period. We then calculated risk ratios for vaccination as compared with no vaccination and estimated the vaccine effectiveness as one minus the risk ratio.’