I Got the Moderna Vaccine
Two days before Christmas, I got a phone call: “Can you be here at 2:00?” asked Rebekah, our small county’s (only) Public Health nurse. Yes, I said, and by 2:30 Rebekah had injected my wife and me with the Moderna Covid-19 vaccine.
Getting the Covid vaccine on Wednesday was quite a surprise. Public Health nurse Rebekah Stewart had given Ouray County Emergency Medical Services personnel a briefing on Zoom Tuesday evening. My wife and I are volunteer medics in our rural Colorado county. Our first Covid death was April 8, pretty early in the pandemic for such a rural county.
Rebekah didn’t even have an estimate of when their vaccine supply was arriving, but she wanted us to know the science behind the vaccine’s development. Pfizer’s and Moderna’s Covid vaccines are extremely similar, but as a small county that didn’t have a freezer cold enough to keep Pfizer’s vaccine, we would be getting Moderna’s.
She also went over the expected side effects so, when it was offered to us, we’d have enough information to make an informed decision as to whether we would want it. I had decided long ago that I would take it as soon as it was offered.
So it was quite the surprise to get Rebekah’s call the next morning asking if we could be there at 2:00: our county’s initial supply had arrived by FedEx shortly after the Zoom call. FedEx was already working pretty late with the Christmas rush and Ouray, our county seat, is at the end of the route.
While the CDC provided suggested priority “phases” for vaccine rollout while production ramps up, states are allowed to adjust the priorities. The State of Colorado decided that “Phase 1A” would include the highest-risk healthcare workers — “People who have direct contact with Covid-19 patients for 15 minutes or more over a 24-hour period,” plus long-term care facility staff and residents; “Phase 1B” would include, among others, “EMS, firefighters, police, correctional workers, dispatchers … and other first responders.”
In our county, where EMS has transported multiple patients with confirmed Covid-19, well, we’re in direct contact with patients for a lot longer than 15 minutes. Here, there’s no 5-minute hospital rides: our transports are 20–60 minutes to get to the closest hospital, and that’s on top of any time we spend evaluating, treating, and loading them up before we can start moving. Our health department, then, decided to move EMS personnel into the first priority phase. Since we tend to be available at a moment’s notice, that’s how we — along with the longest-serving dentist in town and his assistant — ended up getting the shots from the first 10-dose vial.
When we arrived, our little Public Health department didn’t want anyone but their own employees inside the building, which helps keep it from getting contaminated, such as by people not knowing they have Covid. So we actually had to bare our arms, one by one, in the parking lot out front: it was lightly snowing, and 18 degrees (-8 centigrade), and then we had to stay there for 15 minutes to ensure none of us had any severe reactions. None of us did.
But let’s back up a little and talk about vaccine efficacy and effectiveness, which sound like they “should” be the same thing, but aren’t, and what they mean since I muddied the waters a little bit by not being clear and detailed enough in my previous article.
Setting the Bar
Back in June, the U.S. Food and Drug Administration announced that to win approval, any Covid-19 vaccine would have to prevent the disease — or decrease its severity — in at least 50 percent of the people who receive it. Also, they said, the group of test subjects should include a wide age range, and include minorities.
FDA Commissioner Stephen Hahn assured Congress the agency would follow established scientific principles, and “will not cut corners in our decision-making.”
That 50 percent figure, which refers to efficacy, was criticized for both being too low, and too high. 50 percent is “a realistic goal but not a very high bar,” said Dr. Peter Hotez, Professor of Pediatrics and Molecular Virology & Microbiology at Baylor College of Medicine in Houston, Texas. But even 50 percent wouldn’t be the end, he said, adding “Our first vaccine won’t be our best.”
“I would hope we could do better than 50 percent,” agreed Dr. Paul Offit, Professor of Vaccinology and Pediatrics at the Perelman School of Medicine at the University of Pennsylvania, as well as the director of the Vaccine Education Center at The Children’s Hospital of Philadelphia. The cutoff, though, is “generally reassuring because the FDA said it wouldn’t approve a vaccine unless it was effective.” Which, you may be starting to realize, is relative.
On the other hand, Dr. Stephen Ostroff, the FDA’s Chief Scientist and former acting commissioner, thought the 50 percent figure was too high a bar. “A vaccine that has efficacy of less than 50 percent may still be very beneficial for people at high risk of developing the disease,” he said. With the virus “rampaging through a lot of parts of the United States, I would certainly consider a vaccine with less than 50 percent efficacy.”
Racing to Find Efficacy
Pfizer recruited 43,661 volunteers to test the vaccine candidate, with about half randomly assigned to a placebo group, which means they were injected with saline, or sterile water with the same amount of salt as in our bodies, and the rest got the actual vaccine. To get to a statistically significant result, they then had to wait until 170 of those test subjects caught Covid.
Ironically, the surge in cases as colder weather rolled in “helped” (if I can use that word) to push the test subjects to 170 Covid cases.
No one in the test group knew if they got saline or the actual vaccine, and neither did the people who gave them the shots, which is called a “double blind” study — researchers want to ensure there is no psychological influence. Interestingly, the placebo group reported a significant level of side effects too, even though they didn’t actually get the vaccine: psychology really does play a large part in that.
But as the reports of Covid cases came in among the 43,661 volunteers, Pfizer’s computers knew who got the placebo, and who got the vaccine candidate. And of the 170, just 8 were from those who got the vaccine; 162 got the placebo. Do some simple math and find those 8 who got the vaccine among the 170 Covid cases is a hair over 4.7 percent, which leaves the efficacy at 95.3 percent, which Pfizer rounded down to 95 percent. *
With the FDA expecting at least 50 percent efficacy, “Hearing that at the interim analysis we are over 90 percent effective — it was almost stunning to hear,” said Dr. Kathrin Jansen, Pfizer’s chief of vaccine research and development.
It was unprecedented.
Efficacy vs Effectiveness
Yet, that’s efficacy, not effectiveness. What’s the difference?
Efficacy is determined by testing in “best case scenario” conditions: a double-blind randomly controlled trial as just described. In addition, researchers have really tight controls on how the vaccine is stored, how it’s given to each test subject, and how those subjects are closely monitored. It’s one of the reasons vaccines are expensive: it’s a detailed process. And, it takes awhile.
What’s not a “best case scenario” is when those careful safeguards go out of the developers’ control: are the vials really kept at around −94 degrees Fahrenheit, in the case of the Pfizer vaccine? (Which is −71 degrees centigrade. That’s one cold freezer.) Moderna’s only needs to be kept at −4 degrees Fahrenheit (−20 degrees centigrade, which just about any freezer can do).
In the case of both the Pfizer and Moderna vaccines, once a vial is taken from the freezer and opened, the doses have to be used within six hours, or whatever is unused has to be thrown away because it degrades so quickly. You can bet that procedure was followed to the letter by the researchers. Do busy public health departments and hospitals follow the rules that closely? We hope so, but it’s hard to know for sure, and we can’t know for sure if every person who gets the vaccine will report back if they get sick later. They could, for instance, figure they caught a cold, not Covid. They might not get the second dose on time, or at all.
So if the “best case scenario” is a 95 percent efficacy, a number that will certainly change at least slightly as more of the volunteers get Covid (which is probably why Pfizer rounded down), then what’s the “real world” effectiveness going to be?
Something different — something lower. And that’s the difference between efficacy and effectiveness: ideal conditions versus real world conditions.
But remember part of the definition that the FDA laid out in the first place: to win approval, that 50 percent efficacy requirement, was that the “vaccine would have to prevent the disease — or decrease its severity.” We know the vaccine won’t necessarily make you immune to Covid-19, but it’s still worth it for that reduction in severity if you do get it.
And remember, even when properly vaccinated under “best case” conditions, so far 8 of the volunteers still got Covid: none of the vaccinated population will really know if they’re “immune” from Covid. Any one of them can still get it, and be contagious, so that’s why we need to continue with the usual safeguards — wearing masks, social distancing, washing hands — even after getting the vaccine.
Interestingly, I found when researching this that while both Pfizer’s and Moderna’s vaccines are nearly identical — but not fully so, which is obvious when you consider their vastly different required storage temperatures — Pfizer’s contains 30 micrograms of vaccine, while Moderna’s has 100 micrograms. Yet Moderna’s efficacy is a little bit lower: 94.1 percent. That’s also subject to change as their studies continue, and maybe Moderna’s and Pfizer’s numbers will converge, but it goes to show that more isn’t always better.
More might — or might not — also create more side effects. After my first shot 2 days before Christmas, I felt fine. The next day, my arm was sore at a level I described to the CDC as mild. On Christmas, less sore. And a day later, I had to poke at the injection site on my arm to feel it at all. Sunday, as I’m recording this, I don’t even have pain if I hit my arm. I did sign up with the CDC’s vsafe program, discussed in my previous article, and that’s how I reported all of that to them. But I never felt anything else, no other side effects, from my Moderna injection.
Some reports say that the second dose reactions can be more intense, but starting where I am, even if it’s 10 times worse, which seems unlikely, it would still be somewhere from mild to moderate, for a very short time. I’ll take that any day over getting Covid, since even symptom-free cases still develop long-term complications with lungs, heart, and other organs. No thanks!
I’m absolutely one of the lucky ones to get vaccinated so early, especially considering my little county can’t even handle the Pfizer vaccine, and had to wait for Moderna’s to be approved.
Pfizer expects to ship 50 million doses by December 31st — enough for 25 million people to get both doses, three weeks apart, and 1.3 billion more doses during 2021. Obviously, the U.S. doesn’t get all of those: other countries have also received their first shipments, with more to come soon.
Moderna, meanwhile, which requires two doses 4 weeks apart, said they expect to ship 20 million doses by the end of the year, which is coming right up.
The Trump Administration’s Operation Warp Speed officials previously said they expect 20 million Americans to have their first shot of one vaccine or the other by the end of the year, and 100 million by the end of March, which could increase if we get another effective vaccine approved before then. But, so far, they’re behind that expected pace. That’s partly the difference between “best case scenario” and “real world conditions.”
The only question that remains to be answered is, how long with the vaccine last? Only time will tell, but the two companies have tens of thousands of volunteers who got the vaccine long before you will, so they’ll know that answer before you need any sort of booster.
My bottom line remains, when you get the chance, get the vaccine unless you have a condition your doctor says makes you a very high reaction risk, in which case you should definitely at least strongly encourage anyone near you to get theirs to help protect you.
My previous article on the vaccine explains why it’s impossible to reach herd immunity without massive health impacts (and a huge death count):
Beating the Vaccine Scare-Mongers
Something to consider before getting the vaccine — or deciding not to.
Reader Tom in Ohio commented on my math, saying it was a bit too “simple”:
Word problems are notoriously difficult, both to construct properly and to convert to and from math equations. 8 of ~20,000 that got the vaccine got Covid. 162 of ~20,000 that did not get the vaccine got Covid.
“Something” caused the lower number of infections for those that got the vaccine. Had 85 of each group been infected, then the vaccine wouldn’t have worked at all. Part of the issue is that the resulting percentage from the division is the negative result. Those for which the vaccine was not effective. One needs to divide one side by the other, not one side vs the total. 85/85 equals 100%: had that been the result, we’d know that the vaccine is ineffective 100% of the time. With 8/162 we know that the vaccine was ineffective 4.9% of the time. (Since the number 8 is so small, using 170 as the denominator gives a reasonable, but incorrect, answer).
Because 8/162 is so very close to 8/170, the mistake is easy to make and also has no material impact on the discussion (aside from trying to understand the math).
Thanks for the correction, Tom.