First, it shows vaccines *can* prevent COVID illness in humans, and it validates the spike protein target. We didn't know these things before today, and it's good news for all #COVID19 vaccines in development. 1/
Second, the early efficacy is quite high, although it may wane over time. We can't say anything about duration of protection yet, but it helps to start from a high level of efficacy. Higher efficacy reduces the uptake needed to significantly dampen virus transmission. 2/
Third, this is the first time an mRNA vaccine has demonstrated efficacy in a human Phase 3 efficacy trial. That has significant ramifications for the mRNA platform as well as immunization more broadly. Much more will be written on this in the future. 3/
Fourth, this could have major implications for emerging infectious diseases (EID) preparedness, given the "plug-and-play" nature of mRNA vaccines and emphasis on chemistry over biology in manufacturing. Important note: there is no guarantee mRNA will work against all targets. 4/
Having cited all of these *potential* benefits, many questions remain unanswered: duration of protection, efficacy against severe disease, protection of older adults, long-term safety, etc. We'll learn much more when the data is published and with long-term follow up. 5/
The bottom line is that this is very good news for COVID vaccine development and the world's pandemic response. There are sure to be surprises and setbacks in our vaccine efforts in the future, but we can all cheer today's news. 6/
Disclosures: I don't have a financial interest in any company developing a COVID vaccine. Takeda has partnered with Novavax to manufacture and distribute their vaccine in Japan, and with Moderna to distribute their vaccine in Japan on a one-time basis. 7/
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THREAD
In light of the Pfizer #vaccine news, a natural question is whether it's feasible to develop “better” #COVID19 vaccines after the first ones are approved?
The answer is yes. It can be complicated but there are ways to do it. 1/
First let’s break this down into three questions:
▪️ Why might we want better vaccines?
▪️ Why would it be hard to study new vaccines?
▪️ What are the options for doing this? 2/
WHY MIGHT WE WANT BETTER VACCINES?
After we’ve seen full Phase 3 datasets on the first vaccines, we may desire better efficacy in certain populations, longer protection, greater impact on transmission, improved dosing schedule, or an improved safety profile. 3/
To be clear, it's not impossible, and OWS surely has assumptions to support this. And yes we must be ambitious.
But many will assume and/or communicate that these *targets* are what they can *expect* to happen, when there are many unknowns and execution risks. 1/
A few big ones: (1) we don't have *any* efficacy data, incl in elderly; (2) manufacturing scale-up is complex and delays very common; (3) first-time cold-chain, distribution and logistics; and (4) presumably more than one vaccine needs to succeed for this to happen; etc. 2/
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/
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/
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/
This is a thread on the use of antibody tests (serology) to gauge individual risk for COVID-19 infection. It's triggered by the recent @WHO guidance and the push for "immunity certificates" to get people back into the workplace. @jeremyfarrar@laurie_garrett@mvankerkhove 1/8
The science isn’t there, and it could get us into trouble for two reasons: partial immunity and risk perception. A history of COVID-19 and/or circulating antibodies may not translate to complete protection in all individuals. This is the case for circulating coronaviruses. 2/8
We’ll likely see spectrum of protection, with many people having "partial immunity," meaning that they can be reinfected but with less severe symptoms or no symptoms at all. These individuals may "shed" lower amounts of virus but could still infect others. 3/8