Does the Johnson & Johnson vaccine protect against the delta variant of COVID?

johnson and johnson vaccine against delta variant
Photo via New York National Guard/Flickr (CC BY ND 2.0)
  • This story is regularly updated for relevance. Last updated: Aug. 4, 2021

After the World Health Organization listed the delta variant of COVID-19 as a “variant of concern,” many people began to question the efficacy of their COVID-19 vaccines. The single-dose Johnson & Johnson vaccine is of particular concern in the fight against the delta variant. 

The delta variant, also known as B.1.617, was first discovered in India but has since been found in dozens of other countries. In the United Kingdom, the delta variant is now “essentially taking over as the dominant variant,” according to Dr. Anthony S. Fauci, the nation’s leading infectious disease expert. 

The delta variant is also about 60% more transmissible than the original coronavirus, and it’s been called by one former Biden administration official as “COVID-19 on steroids.” 

In the U.S., the delta variant accounts for more than half of new cases. Studies have shown that Pfizer is doing well at protecting against the delta variant—and experts think Moderna has similar results—but early evidence for the Johnson & Johnson vaccine indicated that the Johnson & Johnson vaccine is somewhat less effective than Pfizer and Moderna. 

Dr. Scott Gottlieb, former Food and Drug Administration commissioner said the Johnson & Johnson vaccine appears to be about 60% effective against the delta variant, while the Pfizer and Moderna vaccines are about 88% effective after the second dose. But an Israeli study in early July showed the Pfizer effectiveness against that variant had dropped to 64%.

“We have the tools to control this and defeat it,” Gottlieb told CBS’ Face the Nation. “We just need to use those tools.”

In July, Johnson & Johnson—which got bad news when a handful of people who got the vaccine developed Guillain–Barré syndrome—said its vaccine “generated strong, persistent activity against the rapidly spreading delta variant” and performed even better against that variant than it did for the beta variant.

In early August, Johnson & Johnson was still confident in its vaccine, even as a small percentage of fully vaccinated people caught COVID anyway.

“All authorized COVID-19 vaccines have been shown to help prevent infection and reduce the severity of illness, which is why COVID-19 vaccinations are such an important tool to help end the pandemic,” the company told Fox News. “As noted by the CDC, though a small percentage of people who are fully vaccinated can still get COVID-19, developing severe illness is still a rare occurrence.”

“Of the 469 cases of breakthrough infections observed in the town in Barnstable County, Massachusetts, only 1.2% were hospitalized. As of July 27, no deaths were reported in the cases the CDC studied, which is a sign vaccination is working as intended.”

The delta variant is even more concerning for those people who have not gotten a COVID vaccine yet—the Johnson & Johnson version or any of the others. In a recent viral Twitter thread, Dr. Robert Wachter—the chair of the University of California, San Francisco’s department of medicine—wrote, “If you’re fully vaxxed, I wouldn’t be too worried, especially if you’re in a highly vaxxed region … If you’re not vaccinated: I’d be afraid. Maybe even very afraid.”

Read more on the delta variant: 

Sources: CBS News, Axios,

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