And welcome back! It’s been (checks blog) three months since my last post! Wow! I have no real excuses other than being busy. But, this past week brought some great news for public health that I just had to post about: a third COVID-19 vaccine has been authorized for emergency use in the United States!
According to the CDC, over 59 million Americans – nearly 1 in 4 U.S. adults – have gotten at least 1 dose of a COVID-19 vaccine, and 30 million have gotten 2 doses. That is amazing progress for vaccines that weren’t even available 3 months ago! Still, if you’re one of the majority who haven’t yet started the COVID-19 vaccine, you may be wondering which one is best for you, especially now that there’s another option available.
First and foremost, I stand by my earlier recommendation to get whatever COVID-19 vaccine your doctor, employer, clinic, or pharmacy has in stock. The best COVID-19 vaccine for you is whatever vaccine you can most easily get. But if you’re in the enviable position of being able to choose between more than 1 vaccine, then read on for my thoughts.
I’ll start with the only scenario where I’d say there’s a definitive answer: if you or someone you’re arranging a COVID-19 vaccine appointment for are 16 or 17 years old, then get the Pfizer COVID-19 vaccine. As of this writing, it’s the only COVID-19 vaccine authorized for use in 16 and 17 year olds in the U.S. Pfizer and Moderna both have clinical trials studying use of their COVID-19 vaccines in ages 12 years and up, and Johnson & Johnson is reportedly planning to study use of its COVID-19 vaccine in infants, so there may well be COVID-19 vaccines available for younger children later this year. But for now, if you want to get COVID-19 vaccine for a 16 or 17 year old, Pfizer’s your best (and only) option.
Pfizer vaccine vs. Moderna vaccine? If you have a choice between either of these vaccines, it’s a coin toss. They’re both made using similar mRNA technologies, they have similar effectiveness and similar side effects, they’re recommended for the same group (aside from 16 and 17 year olds) and they were authorized within a week of each other so there are nearly equal amounts of data available about their use. Pick whichever one is available closest to your home or has the soonest appointment, or if they’re both equally available to you then toss a coin. They’re both excellent vaccines and I truly can’t choose one over the other.
Janssen (Johnson & Johnson) vaccine vs. mRNA (Pfizer or Moderna) vaccines? Here’s where it gets trickier. The newest COVID-19 vaccine, created by Janssen Biotech, a subsidiary of Johnson & Johnson, is different enough from the Pfizer and Moderna vaccines that a lot of scientists and members of the media are reasonably asking which one is better. Right now, there’s no clear answer. I realize that there are so-called experts claiming otherwise, but they truly aren’t directly comparable, nor are their studies. It comes down to personal preference and local availability.
First, let’s discuss why you shouldn’t listen to so-called experts who draw conclusions based on a single data point. A lot of people have pounced on the estimates of vaccine effectiveness from the various studies. After all, the Pfizer and Moderna estimates were within 1 percentage point of each other but the Janssen estimate was notably different; surely that means something doesn’t it?
Not really, no.
If you want to make a valid and reasonable comparison between 2 data points, you need to be sure you are comparing the same thing. And unfortunately, the Janssen study used a different definition for vaccine effectiveness than the Pfizer and Moderna studies did. Comparing estimates using two different definitions would be like comparing measurements made using two different scales without knowing how those scales compare against each other. If Johnny’s dog is three cubes tall and his cat is four apples tall, then which pet is taller? It’s impossible to answer without either measuring them both with the same scale or comparing them directly against each other. Right now, we don’t have any direct comparison of Janssen’s vaccine against Pfizer’s and Moderna’s, and it would be foolish to conclude whether it is better, worse or similar to them.
It’s also important to consider the context under which they were studied: the Pfizer and Moderna vaccines were studied last summer and fall before COVID-19 variants had been identified and possibly before they had emerged in the areas where the vaccine studies had occurred. Later studies have suggested that both vaccines may be less effective against the South African variant, and possibly against the Brazilian variant as well, than the initial estimates suggested. In contrast, the Janssen vaccine was tested in South Africa and Brazil and demonstrated fairly good efficacy against the strains circulating in those areas.
The Janssen vaccine has several pros, many of them related to convenience: the single dose series means that you’ll achieve immunity sooner than you would after the 3- and 4-week Pfizer and Moderna vaccine 2-dose series, respectively. You’ll also save yourself a second trip to the vaccine clinic; if your nearest COVID-19 vaccine clinic is a few hours’ drive away, that may be a serious benefit. It also has much simpler storage conditions, which means that it will probably be easier for healthcare providers to bring it to harder-to-reach locations. Additionally, while the side effects have not been compared head-to-head, participants in Janssen’s clinical study appeared to report fewer side effects than participants in the Pfizer and Moderna studies. If nothing else, they only had side effects after 1 shot instead of after 2 shots.
The Pfizer and Moderna mRNA vaccines have their own pros: right now, there are more doses of these vaccines available in more locations (although I expect the Janssen vaccine availability to increase in the coming weeks). The CDC has been studying them closely over the last 3 months, and there’s more information available on how they work and what to expect. Healthcare providers are more familiar with them (although this, too, will change as the Janssen vaccine becomes more available). And as much as I urge caution in directly comparing vaccine effectiveness estimates, I can’t deny that reports of 94-95% effectiveness are enticing.
Ultimately, I stand by what I’ve said several times before: get whatever COVID-19 vaccine is most available to you.
On a personal side, both I (as a healthcare worker) and my parents (as people over 65) have gotten our COVID-19 vaccines now. When I became eligible, the closest clinic with the soonest appointment had the Moderna vaccine, and I had no hesitation about getting it. When my parents became available, the soonest appointment they could get was at a mass-vaccination site that carried Pfizer vaccine, and I had no concerns about their getting the Pfizer vaccine. If a friend or family member told me that the soonest appointment they could get was for the Janssen vaccine, then I’d tell them to get it without any qualms about that vaccine either.
Stay healthy, stay safe, and get your COVID-19 vaccine when you’re eligible and able to get one,
š Dr. B