The Pfizer vaccine works for adolescents!
But, I, of course, have questions.
The Pfizer vaccine works for adolescents! You can read Pfizer’s press release here or NPR’s take here. This my scientific perspective…
Important context:
July 2020: Pfizer/BioNTech started recruiting participants aged 12+ for their Phase III trial (they call this the “Landmark Trial”)
September 2020: Once interim results looked good for younger adults, the trial started for 12-15 year olds. This step-down approach is crucial for safety.
December 2020: Pfizer went up for emergency authorization. At the time, Pfizer had data on 100 adolescents (aged 12-15): 49 in vaccine group & 51 in the placebo. However, this wasn’t enough people to satisfy FDA requirements and evidence was “insufficient to support a favorable benefit-risk determination at this time”. So, Pfizer only requested emergency authorization for 16+ years
March 2021: Pfizer has data on 2,259 participants were between the ages of 12-15: 1129 in the placebo group and 1,131 in the vaccine group
This is exciting news.
There’re two ways in which we measure how well a vaccine works. Efficacy and immunogenicity. This press release had good news about both…
High efficacy: Immunologists hypothesized that the vaccine would be less efficacious among adolescents/children. From this press release, we know that this is not the case. 18 adolescents got COVID19 in the placebo group. 0 adolescents got COVID19 in the vaccinated group. This equates to 100% efficacy. Which is insanely good.
Strong immunogenicity: This is a more complicated metric that measures the type of immune responses that the vaccine generates and their magnitude over time. Unfortunately, there is currently no definitive set values that “define” a protective immune response (we are still working on this). So, we just know that immunogenicity is “higher” among adolescents than what we expected.
Unanswered questions
This is, once again, science by press release. And there are a lot of unanswered questions. We won’t see the raw data until it's released by the FDA a few days before the emergency authorization meeting. I look forward to seeing this, as I have questions:
This is only one month of data. Final efficacy numbers may alter after accounting for at least 2 months of data.
In terms of safety, the press release said the vaccine was “well-tolerated”. We will, obviously, need to dig into this much further.
Adolescents were followed during an interesting time in the U.S.: variants were gaining speed. I’m curious to see if they tracked the variants in this trial, so we can learn more about their impact on mRNA vaccines. Especially, B.1.1.7 which can be easily detected in a PCR test (compared to the other variants which cannot).
During this trial, transmission increased astronomically (Dec) and then plummeted (Jan-Feb). Given the fluctuations, it’s not entirely clear how vaccine effectiveness (i.e. how well the vaccine does in the “real world”) will reflect vaccine efficacy (i.e. how well the vaccine does in a trial). Unfortunately, we won’t know this for a long time.
Next steps
Pfizer is looking to amend their current FDA emergency use approval. I have no idea what this process looks like or the implications on a timeline. But, I will follow closely and let you know soon.
The pandemic is going to end (I hope)
We can’t reach herd immunity without kids. This morning we got confirmation that it is medically possible to reach herd immunity. This is amazing news. But this is only one half of the equation. We’re going to start reaching a point soon in which supply exceeds demand. We need to address vaccine hesitancy (which is, importantly, different than anti-vaxxers) to squash this pandemic once and for all.
Love, YLE
Great news! I'm excited that my kids might get Pfizer by summer given its EUA application. But I see anti-vaxers, or just political conservatives who read different news sources, make a different argument; I think they're wrong in at least one way (they typically don't cite any evidence), but I'm not sure exactly where they're wrong, and I don't want to just dismiss them out of hand. Here's their argument: 99.9% of kids who get infected aren't harmed by the virus, but some are harmed by the vaccine (or alternatively, the vaccines are experimental so we just don't know if it harms them). Adults will protect themselves by getting vaccinated. Therefore you shouldn't be risking your kids' health by making them get a vaccine. Where is that argument wrong (if it is wrong)? On the risk to kids from COVID? On the risk of the vaccines? On the unknowns? Of course, we need kids to get vaccinated to stop the spread of the virus and the opportunities for it to mutate, but people making these arguments typically don't have the broader public good in mind, so leave that aside for now, if possible.
Thank you so much for your helpful insights! I really appreciate all of the time and effort you put into helping us understand what's happening.