Johnson & Johnson’s Covid-19 vaccine is 100% effective at preventing death:
How to keep track of the rest of the numbers, even as they change
By Kristin Levine
On Saturday, the United States approved another Covid-19 vaccine that could help overcome the vaccine supply issues drawing out the pandemic. Recently, we’ve seen a lot of uncertainty online around Johnson & Johnson’s vaccine’s overall efficacy rate of 66%. While this is lower than Pfizer’s and Moderna’s almost 95% efficacy rates, the Johnson & Johnson vaccine is 100% effective against preventing Covid-19 deaths. A lot of the online confusion seems to come from the question: how do we know if a vaccine is “good”?
Is a good vaccine one that prevents all cases of Covid-19, even mild ones? In that case, it is not as effective as Pfizer’s and Moderna’s. But, is preventing deaths what makes a vaccine “good”? Of the 44,000 people who participated in Johnson and Johnson’s clinical trials, not one who received the vaccine died of Covid-19. By this criterion, the Johnson & Johnson vaccine is just as good as the Pfizer and Moderna vaccines.
Another advantage of the Johnson & Johnson vaccine will be much easier to distribute and administer. The Johnson & Johnson vaccine doesn’t require storage at crazy cold temperatures, and it’s only one dose, while Pfizer and Moderna each require two. In real life, how many people might not show up for their second shot? If ease of use is a criteria, Johnson & Johnson’s vaccine sounds like it might be the best choice.
Let’s take a closer look at some of the confusion we’ve noticed online:
Online Uncertainty
This person is right — it is confusing because all of these numbers mean something different: overall the vaccine is 66% effective at preventing ALL cases of Covid-19 — mild, moderate and severe; In the United States, it’s 72% effective against moderate and severe disease, and 85% effective against overall severe disease. We’d like it to be simple, like the approximately 95% efficacy touted for the Pfizer and Moderna vaccines, but there’s just no way to have one number accurately describe all the data.
Here’s another reaction:
This reply was pretty amusing:
The most important statistic is buried here: the vaccine is actually 100% effective against hospitalization and death. That means no one who got the shot and caught COVID died. Was it less effective against mild disease? Yes. But it’s the severe cases that cause death. And as we mentioned, the Johnson & Johnson vaccine has some real administrative advantages — it requires only one dose and can be stored at more normal temperatures.
This confusion isn’t limited to Johnson & Johnson’s vaccine. When the Pfizer vaccine was first released we saw similar confusion online:
Communicating Shifting Statistics
It sounds like this person is referring to Pfizer’s interim analysis from early last November. At that time, 94 people out of 43,538 participants, contracted COVID-19, and the company reported 90% efficacy in preventing COVID-19. By the time Pfizer applied for emergency authorization only a few weeks later, 170 people had gotten sick, 162 in the placebo group and 8 in the vaccine group. This additional data changed the numbers. The vaccine now appeared to be 95% effective. So the writer wasn’t wrong — the numbers are confusing and changing. But it doesn’t mean they were inaccurate, and those 94 people were definitely not “hand picked.”
So to dismiss the Johnson & Johnson vaccine as “worse” than its competitors overlooks the story. If you’re judging it on its ability to prevent all cases of Covid-19, then yes, it is less effective. If you’re looking at its ability to prevent hospitalization and death, then it’s just as good. And if you’re judging on ease of use and administration, which is critical to widely distributing the vaccine and ending the pandemic, it’s actually much better.
The challenge is how to communicate to the general public these nuances. And it’s not a challenge that ever really ends because numbers are still changing. For example, Pfizer and Moderna’s vaccines reportedly have reduced effectiveness against some of the coronavirus variants, while Johnson & Johnson’s vaccine appears to remain effective, even against the South African variant. We should expect to see efficacy rates shift and change depending on which strain of the virus is circulating in a particular area. But it’s not a conspiracy — it’s just science.
