CDC data confirms J&J is the worst-performing COVID-19 vaccine in the US - but being unvaccinated is far more dangerous

• The CDC has released data breaking down COVID-19 cases and deaths by vaccination status, as well as vaccine brand.
• The data shows "firstly, the vaccines work," an independent immunologist said.

Two COVID-19 shots work better than one.

For the first time, the Centers for Disease Control and Prevention is sharing data from across the US on COVID-19 cases and deaths, broken down by vaccination status, as well as vaccine brand.

With this more granular data available, clear trends are emerging showing Pfizer and Moderna's two-shot vaccines work best at preventing all kinds of COVID-19 infections.

"Firstly, the vaccines work," immunologist John Moore from Weill Cornell Medical College told Insider, as he reviewed the new data. "The difference between vaccinated and unvaccinated is huge."

That's true. In August, the risk of catching COVID-19 was more than six times higher for unvaccinated people, according to the CDC's new graph.

Still, there's a "split in the potency of the vaccines with J&J and the other two," Moore said.

Moderna's vaccine (green line) seems to have the edge, while Johnson & Johnson's one-shot vaccine (in orange) isn't holding up as well.

This new data (taken from 16 different health departments representing 30% of the US) goes along with what other real-world studies have found.

J&J's single shot vaccine isn't as good as the others at preventing coronavirus infections. Part of the reason for the difference might be that one exposure to a pathogen isn't enough to stimulate a really robust immune response. (That's another reason why it's a good idea for people who've had COVID-19 to get vaccinated.)

Mounting evidence J&J should be a 2-shot vaccine

The data comes at a critical time, as an independent advisory committee to the US Food and Drug Administration voted unanimously Friday to support booster doses for everybody who's gotten J&J's vaccine.

At the meeting, Peter Marks, who directs the FDA's Center for Biologics Evaluation and Research, said "there is some concern" about "the idea of the Janssen [J&J] vaccine as one dose."

"All of the data do not fully align with this being a vaccine that retains excellent activity over time against all forms of disease, or even against severe forms of disease," Marks said.

Indeed, according to the new CDC charts, J&J's vaccine isn't protecting people against death in the same way that the other vaccines are. Fewer than one in every 100,000 people vaccinated with Pfizer or Moderna's vaccine have died from COVID-19, but for J&J, the number is roughly double that.

Dr. Amanda Cohn from the CDC told the FDA panel Friday that the real-world effectiveness of J&J's vaccine is "hovering" around 50-60% overall, and it is only 68% effective at keeping people out of the hospital, which is "substantially lower than the mRNA vaccines."

The risk of death for fully vaccinated people under the age of 65 is virtually non-existent

Not everyone who's vaccinated has the same risk of death. Older adults don't mount as good of an immune response to vaccines as younger people do, while people over the age of 80 are especially vulnerable to severe disease, even if they are vaccinated.

"It's essentially unheard of for vaccinated people under 65 to die of COVID-19 after vaccination," Moore said.

The new CDC data shows that clearly, with the solid green, turquoise, and orange lines for vaccinated people under the age of 65 remaining flat:

Moore said younger people who've had the J&J vaccine still don't need to worry, even if they only have a single jab on board. His own son and his partner, both in their 30s, have had J&J.

"They're not panicking about it, and I'm not panicking about them," he said. Still, he added "I've always said right from the start that J&J is a two-dose vaccine."

While J&J recipients might need a second shot, it doesn't necessarily have to be the same brand. A recent mix-and-match study suggested that people who've had J&J may get a stronger boost from Pfizer or Moderna.

Dr. Penny Heaton, from Janssen's vaccine research and development team, told the FDA committee on Friday, "The bottom line is, single dose, you get a lower efficacy."