With last week’s Pfizer news and this week’s Moderna news, vaccine updates are really exciting.
This is a big deal.
Finally, there’s a potential route to vaccination-facilitated herd immunity that can bring the pandemic to an end.
The speed that vaccines have been developed to prevent COVID-19 (the illness caused by the virus SARS-CoV-2) is an incredible scientific achievement. Just amazing to see.
We’ve gone from identifying the vaccine to having positive Phase 3 clinical trials on two separate vaccines in less than a year.
And the mechanism of vaccination is completely novel. No one has ever made an mRNA vaccine before - and now we have two that work to stop the no-longer-novel coronavirus.
If you’re interested in a deep dive on vaccinations, I would strongly recommend this podcast with Dr. Paul Offit, a vaccine expert at Penn who developed a rotavirus vaccine that has saved tens of millions of kids’ lives worldwide. He’s just an incredible wealth of information who explains things super clearly and will answer many of the questions you didn’t even know you had.
What’s an mRNA vaccine and why does it matter?
mRNA stands for messenger ribonucleic acid. You’re probably familiar with DNA, the molecule that stores our genetic information. RNA is DNA’s cousin.
RNA is the translating molecule for turning our genes into proteins. Proteins are the things that have biologic effects. This is how genes work.
An mRNA vaccine injects a genetic sequence from the virus that our bodies use to manufacture a viral protein. Then our bodies mount an immune response to the viral protein.
This is a different method than injecting us with either a live or a dead virus. This harnesses our own biology to produce a viral protein that activates the immune system.
This method of vaccine development was only theoretical until COVID. And now there’s data to demonstrate that it works. Pretty cool.
How much of an accomplishment is this?
It’s beyond astounding.
If you think about a previous example, like the rotavirus vaccine, which took decades to go from viral identification to a successful Phase 3 vaccine trial, coming up with a successful vaccine (or 2 successful vaccines!) in less than a year is an incredible triumph of modern medical technology.
You should be amazed because this is amazing.
What’s different about the Moderna vaccine compared to the Pfizer one?
The most immediately notable difference is the temperature storage and what that means for vaccination logistics.
The Moderna vaccine doesn’t need to be stored at the temperature of dry ice, -70 degrees C. It can be kept at a cool -20 degrees C.
This simplifies distribution and storage considerably. It means an easier time vaccinating more people.
The vaccine needs to be kept so cold because RNA is an unstable molecule and prone to degrading. Higher temperatures mean more breakdown and thus [we suspect] lower efficacy. But the difference in storage temperatures between the Pfizer vaccine and the Moderna vaccine could prove quite important as we move forward.
The Moderna vaccine is given in two doses 28 days apart, which is slightly different than the 21 day period between doses of the Pfizer vaccine.
A big reason to be bullish on Moderna: protection for everyone
Moderna also announced that protection was extended across ages and ethnicities. This is a big deal given what we know about the disproportionate impact of COVID on minorities and the elderly.
From their press release:
The 95 COVID-19 cases included 15 older adults (ages 65+) and 20 participants identifying as being from diverse communities (including 12 Hispanic or LatinX, 4 Black or African Americans, 3 Asian Americans and 1 multiracial).
Protecting those at highest risk is vital. The Moderna news is a step towards that.
Does the Moderna vaccine prevent people from infecting others?
We don’t know yet.
Moderna’s protocol describes many of the details regarding the Phase 3 trial. Similar to the Pfizer vaccine, efficacy is determined by preventing symptomatic infection, which doesn’t necessarily tell us whether it prevents someone from carrying the virus and infecting others.
We care about preventing infection because it means fewer deaths and less illness, but we also care about preventing someone from becoming infectious so that they can’t infect others. We don’t know much about that with either vaccine.
What’s left to know?
I mentioned major remaining questions in my Pfizer newsletter from last week:
Is it safe?
Is it safe?
Is it safe?
Will people take it?
Side effects happen with every single medical treatment that we have.
A trial of tens of thousands is simply insufficient sample size to tell us about larger populations. When you’re giving a vaccine to tens of millions of people, you’re going to see some rare side effects.
This is expected.
Post market surveillance for safety is standard for pharmaceuticals. It’s impossible to predict what we’re going to find. Think about what we saw with COVID: when you’ve got a ton of infections, you see some rare manifestations of disease.
A vaccination program is no different. We should expect some rare, unpredictable side effects. Seeing them in a post-market surveillance when there wasn’t a signal in the clinical trials is not a bad thing - it’s the only way to do figure this stuff out.
All of the news on the vaccine front has been incredibly promising to date. I see nothing with Moderna’s announcement to cause concern.
We’re not at the end yet, but the finish line may finally be in sight.
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