Reprinted with permission from DailyKos
On Nov. 7, Pfizer released a kind of sneak preview of the first batch of data from phase 3 trials of the vaccine developed in partnership with German firm BioNTech. The news that the vaccine appeared to be 90 percent effective was a huge relief, as it showed the basic idea of targeting COVID-19's "spike protein"—an approach taken by many of the vaccines in development—was valid. It also spawned some satisfying outrage from Donald Trump supporters, who accused the pharmaceutical giant of holding off on announcing results until after the election.
Then on Monday, Moderna released the first information from the testing of their vaccine and the numbers looked even better, reaching nearly 95 percent efficacy. And with even more manufacturers slated to report over the next couple of weeks, Pfizer has returned to up the ante with a second set of data that not only boosts their performance to match that of Moderna, but provides critical information missing from previous reports. And perhaps the biggest news: Pfizer's phase 3 study is done.
Pfizer's first batch of data came when the trial hit a reporting trigger at 94 cases of COVID-19. But now the entire trial of over 43,000 volunteers has ended, with a total of 170 cases of COVID-19. Of those, 162 were in people who received the placebo rather than the vaccine. That bumps the overall efficacy to 95 percent, putting Pfizer's vaccine almost exactly on the numbers that Moderna saw in its first set of data. That shouldn't be surprising seeing as both of these are mRNA vaccines targeting the same set of proteins, but it is reassuring.
Even better, the latest data includes information to show that the vaccine was equally effective across a range of ages, races, and genders. Especially important: The numbers indicate that effectiveness was 94 percent for patients over 65, which is fantastic since that's the group most likely to suffer serious consequences from COVID-19.
Also hugely relieving: the safety data. In the trial, there were "no serious safety concerns observed," with the most common effects being fatigue and headache. Considering that this is the first trial of a mRNA vaccine in humans, that's worth celebrating. If this holds true, mRNA may become a dominant technology for quickly developing vaccines in the future, and for creating vaccines that are more targeted and more flexible than previous technology allowed.
Pfizer has already indicated that 50 million doses should be available by the end of the year, and there are some indications that front-line workers could start receiving the vaccine in December. However, because it is a two-dose vaccine with the second jab coming four weeks after the first, even those first groups of healthcare workers would not actually expect to develop immunity to COVID-19 until January. Also, Pfizer's vaccine requires special handling and deep-cold storage. These stipulations could make the vaccine less available in small clinics or pharmacies. Still, Pfizer expects to produce over a billion doses in 2021.
The disclosure that the phase 3 trial is over doesn't mean that the volunteers involved are now on their own. Pfizer will continue to follow volunteers for months or years, checking back for both continued immune response and logging any potential safety issues. It's not clear when members of the placebo group will be told that they were part of the placebo group. In some diseases, this information may not be revealed for years after the end of the study. However, considering both the infectiousness of COVID-19 and the efficacy of the vaccine, it's likely that members of the placebo group will be given the opportunity to receive the actual vaccine almost immediately.
