Originally posted by gaweidert First, I would be very, very cautious about this study. It has N=503 and has not yet been peer reviewed. This is basically the BBC regurgitating a press release that the universities put out to hype the study. Second, because of the urgency of getting these vaccines into people's arms, the experimental design could not permit variation in dosage spacing (or even dosage level). Just to have two groups (control and experimental) required 60,000 volunteers, and you needed a certain number of positive tests in the control group before you could calculate efficacy. With more but smaller groups, you really make the calculations incredibly complex. Three weeks was the best guess the researchers had, and so they put it forward and got good results. To get the sort of data this study uses would have required delaying getting vaccines out to the masses and led to significantly more deaths. (Moderna tested four weeks for reasons known basically only to the study designers. Moderna is also a higher dose of mRNA, coming in at 100 micrograms vs 30 micrograms for Pfizer. Moderna did test 50 micrograms in phase 2 but opted to go with 100 micrograms in phase 3 and for the final vaccine.)
Science has gotten this consistently right. In the face of a devastating pandemic, you find something that is safe and works very well. Then you run with it. You don't wait around until you find the optimal solution. Remember that at this time last year, we were just getting into phase 3 trials and were being told to expect something with an efficacy in the 60–70% range. On their first try, scientists achieved an efficacy rate traditionally associated only with the measles vaccine.
Originally posted by gaweidert Will the J&J booster work for those who got Moderna or Pfizer vaccinations?
I don't believe anyone is running clinical trials on this sort of thing. We're most likely to see evidence from mass data collection in the countries that have pursued mixed vaccine strategies. I go in on Friday for a follow-up blood draw for phase 3 of the Moderna trial. I plan to ask if they're doing the eight month booster thing for trial participants or what we're supposed to do on that. My eight month mark arrives in mid-October.
Originally posted by gaweidert Some 36,000,000 people in the US have had COVID and survived. Do they still need the regular vaccine or will a booster be enough? I have read conflicting reports about how long immunity lasts after you recover from the disease. More data needed here?
How long immunity lasts is going to vary depending on how severe of a case you had and which variant it was. The evidence overwhelmingly supports vaccination for those who have had positive tests before, as Moderna in particular has been shown to be highly effective even against the delta variant, whereas antibodies from infection by the earlier strain have been shown to be much less effective. There is some evidence that vaccination also improves some of the long COVID symptoms in those who have been suffering from it.