July 2, 2021 -- The highly contagious delta variant of the new coronavirus is on the march across the U.S., prompting even fully vaccinated people to wonder whether they’re protected against this new COVID threat.

New data out of the UK, where delta is causing almost all new infections, is reassuring on this point.

A study in the UK that is tracking healthcare workers with regular testing finds that the vaccines are still highly effective against this variant. After a single dose, the vaccines proved to be about 35% effective against getting an infection with noticeable symptoms and 80% effective at keeping infected people out of the hospital. Two doses was even better, reaching 79% effectiveness against symptoms and 96% against the need to be hospitalized.

But what about the one-and-done Johnson & Johnson vaccine?

There’s been little specific information about how this vaccine holds up against delta. This has prompted some to worry that their protection might not be adequate. Dr. Angela Rasmussen, PhD, an influential virologist and principal investigator with the Vaccine and Infectious Disease Organization in Saskatchewan, Canada recently tweeted that she was concerned about delta and would get an mRNA booster after her single J&J shot.

On Thursday, Dr. Anthony Fauci acknowledged the information gap in the White House COVID briefing. He said right now, indirect evidence from the AstraZeneca vaccine, which uses technology that’s similar to J&J suggests even the single shot should still be highly protective.

“We are now looking at neutralization data and soon we will have more firm data which we would make available to you as soon as it occurs,” Fauci said.

In a statement, Johnson & Johnson also said it would share data on vaccine effectiveness against delta “in the near future.” In the meantime, they said, people who’ve had one dose of the J&J vaccine should rest easy.

“We believe that the single-shot Johnson & Johnson COVID-19 vaccine will continue to offer durable protection, and at present there is no evidence to suggest a need for a booster dose to be administered,” they said, citing evidence that it held up well against other variants that first emerged in South America and South Africa.

Very early information, posted in a press release on Thursday also hints that good news is on the way. The data come from the Sisonke study in South Africa, which is regularly testing healthcare workers vaccinated with Johnson & Johnson. The study investigators say that while they are seeing some breakthrough infections, 94% are mild and 2% are severe.

They also say that data coming next week in a scientific publication will shed more light, but that it appears that immune responses to the J&J shot get stronger over time.

“I’m very reassured that the vast majority of breakthrough infections in Sisonke are mild. We believe that recommending booster top-ups with another vaccine is premature,” said Sisonke Co-principal investigator Professor Linda-Gail Bekker in a written statement.

Isaac Bogoch, MD, and infectious disease expert and clinical investigator at the Toronto General Hospital Research Center is more cautious. He says we probably need to watch what infections do in the coming months to know if people need a booster for the Johnson & Johnson shot.

“People are speaking very confidently on the matter,” Bogoch said. “I don't think we have enough information to make that to make that decision, right? And also it's an answerable question. Like give it a minute we'll know what it’s like the United States.”

If boosters are required, he says, the U.S. certainly has plenty of vaccine supply to meet those needs, a privilege available to very few other countries in the world.

Show Sources


Twitter, @angie_rasmussen  10:47am, June 14, 2021

The South African Medical Research Council 

Public Health England: SARS-CoV-2 variants of concern and variants under  investigation in England

© 2021 WebMD, LLC. All rights reserved. View privacy policy and trust info