I have previously provided examples of how the illusion of efficacy over a period of time can be created for a vaccine intended to avoid getting infected with a virus. For example, this article shows that if the vaccine is a placebo (i.e. has no effect at all) it will appear to be effective if there is a delay in reporting infections of those vaccinated. But it is just an inevitable statistical illusion. In
The video assumes the vaccinated group were all vaccinated at the same time at the start of the two weeks? Obviously if you do this and then decide that the vaccine is not effective for two weeks any infections in that period should be ignored. Alternatively treat the whole population as effectively unvaccinated. The vaccinated population should be everyone who has been vaccinated for at least two weeks and the unvaccinated populations as everyone else.
The video assumes the vaccinated group were all vaccinated at the same time at the start of the two weeks? Obviously if you do this and then decide that the vaccine is not effective for two weeks any infections in that period should be ignored. Alternatively treat the whole population as effectively unvaccinated. The vaccinated population should be everyone who has been vaccinated for at least two weeks and the unvaccinated populations as everyone else.