Medical Examiner

Why Even a 66 Percent Effective Vaccine Is Such Good News

The exact efficacy might not matter as much as the increased ease of distribution.

A long line of people waiting on a sidewalk, wearing masks, at night
A last-minute COVID-19 vaccine event at Seattle University in Seattle on Friday after a freezer failure at a nearby hospital. David Ryder/Getty Images

Today Johnson & Johnson shared results from the clinical trial for a coronavirus vaccine that is administered with just one shot, instead of the two, and has an efficacy of 66 percent against moderate to severe disease. In other words: We have another effective inoculation against the virus, and one with slightly different attributes compared with the others already on the market. “This is cause for celebration,” tweeted virologist and Slate contributor Angela Rasmussen.

And yet, because the vaccine is not as effective as Moderna’s and Pfizer’s, one expert described the clinical trial results as “disappointing” to Stat News. Perhaps you feel a little disappointed too. The reason for the lowered effectiveness might be that it might be less effective against new variants—the efficacy is higher in the U.S., at 72 percent, and lower in South Africa, a hot spot for the new variant, at 57 percent. But the most important takeaway is that it still has a high efficacy against severe disease: 85 percent overall, according to a press release from the drugmaker. Importantly, none of the participants in the trial who received the shot was hospitalized for COVID-19, and none of them died. “If you can prevent severe disease in a high percentage of individuals, that will alleviate so much of the stress and human suffering and death,” Anthony Fauci told reporters Friday.

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Plus, Johnson & Johnson’s vaccine has advantages over the other options. In addition to being a single-dose inoculation, meaning that people can be vaccinated faster and with fewer clinic resources, it can be stored longer at warmer temperatures. The vaccine can be kept for up to three months in a normal refrigerator, according to the manufacturer. Moderna’s vaccine can be kept at that temperature for one month, while the Pfizer vaccine stays good for just five days outside of an ultracold freezer or carefully packed shipping container equipped with dry ice. This means that it will be particularly useful in areas and countries where cold storage is an issue.

The announcement of another vaccine with slightly different attributes and possible lower effectiveness brings up immediate questions about which vaccine will be the “best” to get. But getting vaccinated ultimately isn’t an individual matter—it’s a collective one that involves the whole world. Everyone being vaccinated, and less coronavirus circulating generally, ultimately matters more than you having the most protective vaccine in your own body. In that light, another option to deploy to reduce illness and spread is incredibly useful. “An efficacious one-dose, easy to transport vaccine is huge,” tweeted statistician Natalie Dean, adding that she did want to see more on the data behind Johnson & Johnson’s press release. As with anything in this pandemic, we won’t know for a while just how well this tool will hold up to further scrutiny, whether it will be granted an emergency use authorization by the Food and Drug Administration, and how it will work out in the real world, both scientifically and in the tricky and unpredictable mechanics of actually getting the technology to people and into their arms.

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But there is reason to be hopeful—even reason to think that things could go better in some respects with this new tool than the press release numbers suggest. Stat News reporter Helen Branswell pointed out that “the immune response seemed to improve over time,” meaning that it’s possible that the vaccine is more effective if you look at people who are several weeks out from getting it, rather than just a month. It could also be more effective with a booster shot. According to its website, Johnson & Johnson is also running another study with two doses of the vaccine “to see if a second dose might provide greater, or longer, protection.” But knowing now that we have a vaccine that works pretty well with just one dose? That’s good news.

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