A coronavirus vaccine developed by Johnson & Johnson and Beth Israel Deaconess Medical Center started undergoing testing on volunteers in a large study Wednesday, the fourth vaccine candidate to reach that milestone but the first that would offer protection from COVID-19 after one shot instead of two.
Researchers plan to begin dosing up to 60,000 volunteers in the Phase 3 clinical trial in the United States ― including Boston ― and abroad following encouraging interim results of a study of the vaccine in about 400 volunteers, according to officials from J&J and the federal government.
The smaller study has yet to be subjected to peer review and is expected to be published on a preprint server later this week. It showed that a single dose stimulated a robust immune response and caused relatively few side effects, said the officials. Some recipients experienced a fever and flu-like symptoms, but the side effects disappeared in a day or two.
“We are convinced that a single dose could be very efficacious,” Dr. Paul Stoffels, J&J’s executive vice president and chief scientific officer, said in a news briefing. He was joined by Dr. Francis Collins, director of the National Institutes of Health, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and other federal officials.
Dr. Dan Barouch, head of Beth Israel’s Center for Virology and Vaccine Research in Boston, which helped develop the vaccine and tested it in laboratory monkeys, said a single-dose regimen has obvious advantages over a vaccine that requires a shot and a booster dose months or years later.
“Think about yourself,” he said in a phone interview. “It would be so much easier to go to your doctor for a one-and-done shot then to remember to go back for a booster shot. And, of course, on a global scale for a global vaccine campaign, it’s much easier. The amount [of vaccine] you make goes twice as far.”
J&J, based in New Brunswick, N.J., has pledged to make 1 billion doses in 2021 and will provide it on a not-for-profit basis during the pandemic, Stoffels said. The Biomedical Advanced Research and Development Authority, part of the US Department of Health and Human Services, has committed more than $1 billion to enable the company to make and deliver the vaccine.
The three other vaccines in late-stage trials were developed by Cambridge-based Moderna in a collaboration with NIAID, Pfizer and the German biotechnology firm BioNTech, and AstraZeneca in a partnership with scientists from Oxford University. Those vaccines require two doses taken several weeks apart.
Like J&J, Moderna and AstraZeneca have received billions of dollars from the federal government to develop and advance their vaccines as part of the public-private partnership called Operation Warp Speed. Pfizer will receive nearly $2 billion from the government to make 100 million doses of its vaccine if it wins approval from the Food and Drug Administration, but the New York-based pharmaceutical giant declined to take funding up front.
The J&J vaccine trial will enroll 60,000 volunteers at up to 215 research sites, making it the largest late-stage coronavirus clinical trial to date. The sites include hospitals and clinics in the United States, Mexico, South America, Africa, Asia, and Europe. At least one site is in Boston, at Massachusetts General Hospital, according to the website clinicaltrials.gov and a hospital spokeswoman.
Pfizer is testing its vaccine on 44,000 volunteers. Moderna and AstraZeneca are each testing their vaccines on 30,000 volunteers.
The J&J vaccine is entering the late-stage clinical trial two months after Moderna and Pfizer began the first Phase 3 studies on July 27.
Fauci said he expects that interim results of the Moderna and Pfizer vaccines will become available in November or December. He didn’t rule out October but called that “unlikely.” He predicted that researchers will know whether the J&J vaccine works a month or two after the Moderna and Pfizer data are made public.
Stoffels said he expected the large trial of the J&J vaccine will take less time than those for the Moderna and Pfizer vaccines, in part because volunteers will receive only one shot.
“That’s why we still can predict around the year’s end we will have efficacy data,” Stoffels said.
Half of the volunteers in the J&J trial will get the actual vaccine, and half will get a placebo. Neither the recipients nor those administering the shots know who got the real thing.
As with the other vaccine candidates, scientists will assess whether the J&J vaccine works by comparing the infection rates of people who got the vaccine with those who got the placebo. J&J will consider it effective if it prevents 60 percent of COVID-19 cases, higher than the 50 percent threshold set for the Moderna vaccine.
The scientists expect to render a verdict after 154 study participants get sick with COVID-19 while going about their daily lives. That’s expected to happen faster in a study with 60,000 volunteers than in studies with far fewer participants.
However, Stoffels and the federal officials said researchers will begin evaluating the effectiveness of the vaccine after 20 coronavirus infections. It’s possible the company could seek an emergency use authorization from the FDA at that point if the vaccine proved extraordinarily effective.
“You’d need 90 percent efficacy” for that, he said. “That’s unlikely.”
The vaccine developed by J&J and Beth Israel uses the human adenovirus ― which causes the common cold ― to deliver part of the spike protein of the SARS-CoV-2 virus into cells to stimulate antibodies. J&J used this approach to develop a vaccine against Ebola virus disease that recently won marketing authorization from the European Commission.
The vaccine candidate of AstraZeneca also relies on an adenovirus. But that trial is on pause in the United States as a result of serious neurological illnesses in two participants who received the experimental vaccine in Britain.
The Moderna and Pfizer vaccines rely on messenger RNA, the molecule that relays genetic instructions from DNA to the protein-making machinery of human cells. Those vaccines are supposed to teach the body to produce viral proteins after injection, prompting the immune system to react and build up antibodies that would protect recipients against the coronavirus. No mRNA vaccine has ever won approval.
In another apparent advantage, Barouch said, the J&J vaccine can be stored in liquid form at refrigerator temperatures for at least a month, unlike the mRNA vaccine candidates, which must be kept frozen, including when they are shipped around the world.
Vaccine experts say “cold chain” storage of a vaccine can be especially challenging in poor countries.
“The Pfizer vaccine has to be kept frozen at minus 94 degrees Fahrenheit,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, who is working with a biotech in India on a potential coronavirus vaccine based on older technology. “How do you create a distribution network with something as daunting as that?”
Correction: An earlier version of this story said Fenway Health in Boston will be one of the clinical trial sites for the J&J vaccine, based on a listing on clinicaltrials.gov. A spokesman for Fenway Health says the government-run website is incorrect.
Jonathan Saltzman can be reached at firstname.lastname@example.org.