Yes the first COVID vaccines will face challenges, but the overall situation is quite promising. Thread.
First, we can’t predict how good the first vaccines will be - we need Phase 3 data. We shouldn’t assume they will be very effective, poorly-effective, or “so-so.” 1/
First, we can’t predict how good the first vaccines will be - we need Phase 3 data. We shouldn’t assume they will be very effective, poorly-effective, or “so-so.” 1/
https://twitter.com/carlzimmer/status/1315681409504350208
It's true that some "second wave" vaccines will be better, because they're intended to address gaps, but that doesn't mean the first vaccines won't be good.
Second, don't underestimate complexity of aligning multiple Phase 3 vaccine programs around a single master protocol. 2/
Second, don't underestimate complexity of aligning multiple Phase 3 vaccine programs around a single master protocol. 2/
This would have delayed the Phase 3 trials, with a human cost. It's not just about companies aligning with each other and regulators - it requires rigorous matching of the placebo arm with multiple vaccine arms to avoid reaching the wrong conclusions about efficacy. 3/
Third, no matter how effective initial vaccines are, we’ll need to continue masks, physical distancing, etc, until high uptake achieved. Measures will be relaxed over time as population immunity increases. It was never going to be an “on/off” scenario when first doses arrive. 4/
Fourth, we should be able to make comparisons of efficacy and safety between trials, given that the trials are well-controlled and overlap in primary and secondary endpoints. This is routinely done with vaccines. Recommendations will be refined as effectiveness data gathered. 5/
Finally, early licensure of some vaccines won’t prevent testing of subsequent vaccines, given that: (a) placebo-controlled trials can continue in populations where the vaccine hasn’t been deployed;... 6/
...(b) we may identify correlate(s) of protection in the Phase 3 trials that preclude the need for large efficacy trials of subsequent products; and (c) other reasons, some of which are outlined in this paper from a WHO expert panel. 7/
sciencedirect.com/science/articl…
sciencedirect.com/science/articl…
Yes we've never introduced multiple vaccines w/different profiles, and distribution, training, education, monitoring create huge complexity. Planning is needed across the system and with the public to avoid chaos. But 9 mos into the pandemic, the overall picture is promising. 8/
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