Weirdly, they don’t seem to have measured immune response *prior* to the first dose, so we have no way of knowing whether the stellar immune response predated the first dose. No?
They did measure antibodies prior to the first dose. See results in figure on bottom of the submitted pre-print, linked to the 4th paragraph of the NYT article:
https://www.nytimes.com/2021/02/01/health/covid-vaccine-dose.html or directly here:
https://t.co/6EOEZq8tod?amp=1A few of those who had recovered from covid didn't have detectable antibody before vaccination, but it looks like all of them did have a strong antibody response after the first vaccine. So this shows that the memory B cells are still there even without antibody present, ready to quickly produce antibodies when needed.
You can see the speed of that response, since those who've had covid responded to the first vaccine by producing antibodies 5-8 days later, while it took 9-12 days for those who haven't had covid to show that response. In fact, the antibody response of the previously infected was so high after one shot, that it surpassed what the others reached after TWO shots. The NYT article describes some of the machlokes on whether or not this means that those previously infected should get only one shot.