Share on Pinterest

Zuckerberg San Francisco General Hospital made the decision to give mRNA vaccines to people who had the Johnson & Johnson vaccine in conjunction with San Francisco’s Department of Public Health. Jasmin Merdan/Getty Images
  • One hospital is offering an mRNA vaccine dose to people who had a single dose of the Johnson & Johnson vaccine.
  • Zuckerberg San Francisco General Hospital made the decision in conjunction with San Francisco’s Department of Public Health.
  • Health officials are referring to this as a “supplemental dose” rather than a “booster dose.”

One advantage of the single-dose Johnson & Johnson COVID-19 vaccine is its one-and-done convenience.

But amid concerns over its effectiveness against the highly contagious Delta variant, a San Francisco hospital is offering people who have received the J&J vaccine a second dose of either Pfizer-BioNTech or Moderna-NIAID.

Zuckerberg San Francisco General Hospital made the decision in conjunction with San Francisco’s Department of Public Health, reported ABC7 news.

Health officials are referring to this as a “supplemental dose” rather than a “booster dose.”

Dr. Chris Colwell, chief of emergency medicine at Zuckerberg San Francisco General, told ABC7 that this is because the extra dose that people will receive is not specific for the variants.

Both Pfizer and Moderna are developing new versions of their mRNA vaccines that target certain variants. But they’re also testing to see if a third dose of the original formulation — also a “booster” — increases protection against variants of concern such as Delta.

Whatever you call this extra dose, the goal is to provide people with additional immune protection against the coronavirus.

But do people who have had a single dose of the J&J vaccine need a booster? And if so, when?

Dr. Larry Corey, a virologist at the Fred Hutchinson Cancer Research Center and a leader of the COVID-19 Prevention Network, said many questions about COVID-19 vaccine boosters remain unanswered.

However, data that’s available right now suggest that people who’ve had a single dose of the J&J vaccine are well protected against the Delta variant, he said.

In a study published last month in The New England of Medicine, J&J researchers found the company’s vaccine offers lasting protection.

“People had stable antibodies and broader antibodies at 8 months [after immunization] than they essentially did at 8 weeks,” said Corey, who wasn’t involved in that research.

The antibodies also offered protection against the Delta, Beta, and Gamma variants, “which suggests maturation of B-cell responses even without further boosting,” the authors wrote.

Antibodies are just one measure of the immune response to the coronavirus. B cells and T cells also play important roles in fighting the virus and preventing severe illness.

More recently, a press release detailed preliminary results from a real-world J&J vaccine effectiveness study involving almost half a million healthcare workers in South Africa.

In the study, “one dose [of J&J] did really well against Delta and Beta, with respect to mortality and hospitalizations,” said Corey. “Albeit, there was a significant number of breakthrough infections.”

However, the majority of cases that occur in fully vaccinated people do not require hospitalization.

“If you study some of the [coronavirus] cases that have happened with respect to Delta infection, when people have been vaccinated, they are mildly ill,” said Corey.

Overall, the results from the South African study — which was not peer-reviewed — show the J&J vaccine offered 91 to 96 percent protection against dying from COVID-19.

The vaccine’s efficacy against hospitalization was 65 to 67 percent, and was higher — 71 percent — when Delta was the predominant variant in the country.

Although the J&J vaccine offered strong protection against death in the South African study, Shane Crotty, PhD, a vaccine scientist at La Jolla Institute for Immunology, has some concerns.

In a post on Twitter, he said 71 percent effectiveness against Delta hospitalizations is “underwhelming.”

He added that this level of protection is similar to what was seen with one dose of the AstraZeneca vaccine, in a non-peer-reviewed report released in June by Public Health England.

The AstraZeneca vaccine, which uses a similar delivery system as the J&J vaccine, is designed as a two-dose regimen.

In comparison, a recent study, which has not yet been peer-reviewed, found that during July in Minnesota, the Moderna-NIAID vaccine was 81 percent effective against COVID-19 hospitalizations. The study was pre-published August 9 on medRxiv.

The Pfizer-BioNTech vaccine offered 75 percent protection against hospitalization, which is not much higher than a single dose of J&J in the South African study.

A vaccine’s real-world effectiveness can vary from region to region and over time.

After the South African study came out, Crotty reaffirmed his earlier recommendation about boosters following the J&J vaccine.

His decision also took into account the rapid speed at which the Delta variant spreads, and limited laboratory data suggesting that Delta weakens the immunity generated by the J&J vaccine. The data was from a preprint of a study and has also not been peer-reviewed yet.

J&J reported August 25 that two clinical trials showed that a booster dose of its vaccine given 6 months after the initial dose generated a large increase in antibodies.

The studies were only designed to measure the change in antibody levels after the additional dose.

They don’t show whether people who receive a booster are less likely to contract the coronavirus or develop severe disease.

The data has not yet been published in a peer-reviewed scientific journal.

The company intends to submit its data to the Food and Drug Administration for review, reports The New York Times.

Dr. Ann Falsey, a professor of medicine and infectious diseases at the University of Rochester Medical Center in New York, thinks we need more data on boosters before recommending them to millions of people.

“I really do think it’s a good idea to collect the data, examine it, and be thoughtful about it,” she said, “especially since all the vaccines protect quite well against severe disease.”

One ongoing clinical trial will examine the benefits of mixing and matching boosters. Falsey and her colleagues are leading the Rochester site of this study.

Participants who are fully vaccinated will receive a booster dose from a different manufacturer — including an mRNA booster after a single dose of the J&J vaccine, or a second J&J dose as the booster.

“Would there be benefits from a boost [after J&J]? I think it’s likely,” said Falsey. “But again, that’s why we’re doing this study.”

Researchers will also monitor the side effects experienced by people after the booster dose.

“The first step is just making sure that when you’re boosting people, it’s well tolerated,” said Falsey.

So far, there doesn’t seem to be any combination of vaccines in the booster trial that causes side effects noticeably different from the original vaccine regimen, she said.

This is in contrast to a study released earlier in the spring, which found that mixing and matching the AstraZeneca and Pfizer-BioNTech vaccines resulted in higher rates of side effects, such as fever, compared to two doses of the same vaccine.

Falsey said her medical center receives calls all the time from people asking about booster doses. She tells them: “We’re doing those studies now, and we’ll get back to you on that.”

The CDC’s vaccine advisory committee met again on August 13 to discuss the need for boosters and the current data on their effectiveness.

Dr. Joanna L. Drowos, a family medicine physician at Florida Atlantic University, thinks boosters should first be recommended for certain populations.

“We have some data that people who are immunosuppressed — such as transplant patients or other people taking medications that suppress their immune system — are not getting the same protection from the vaccine,” she said. “So I think boosters will come first for them.”

This would include people who have received a single dose of the J&J vaccine, as well as two doses of an mRNA vaccine.

Corey thinks older adults that have chronic medical conditions should also get a booster dose.

“We know that their immunity [after immunization] was never that good in the first place,” he said. “It was good, but it wasn’t great.”

On August 12, the FDA authorized additional doses of the mRNA vaccines for people who are immunocompromised. These are not considered “booster” doses because these people don’t generate a robust immune response to two doses.

The agency is expected to approve COVID-19 boosters of the mRNA vaccines for Americans 12 years and older, with third doses available as early as September 20.

When patients ask Drowos about whether they need a booster, she recommends they follow the data.

While we still need to learn more about the benefits of boosters, she said the data is clear that people should get fully vaccinated.

Hospitalizations are spiking in areas of the United States with low vaccination rates, with the majority of COVID-19 patients in the ICUs unvaccinated.

“I would rather see people who are not yet vaccinated, get vaccinated,” said Drowos, “before focusing on re-vaccinating people.”