It’s one of five candidates cited by the Trump administration as most likely to work.
An experimental COVID-19 vaccine developed partly by Beth Israel Deaconess Medical Center will be tested in humans starting in July, two months earlier than originally scheduled, according to Johnson & Johnson, the health care giant collaborating with the Boston hospital.
Johnson & Johnson said Wednesday that the vaccine appeared so promising in preclinical studies that the partners were able to push up the start for testing in healthy volunteers to the second half of July. The vaccine uses a common-cold virus to deliver a coronavirus antigen into cells to stimulate the immune system to fight off an infection.
“Based on the strength of the preclinical data we have seen so far and interactions with the regulatory authorities, we have been able to further accelerate the clinical development of our investigational SARS-CoV-2 vaccine,” said Dr. Paul Stoffels, chief scientific officer for Johnson & Johnson.
The federal Biomedical Advanced Research and Development Authority, or BARDA, and Johnson & Johnson have invested more than $1 billion in the effort.
There are at least 125 potential coronavirus vaccines in development worldwide, according to the World Health Organization. The one created by Beth Israel and Johnson and Johnson is one of five that the Trump administration has said are most likely to succeed, the New York Times recently reported.
The administration has launched a program called “Operation Warp Speed,” with the ambitious goal of rolling out a safe and effective vaccine by the year’s end. Vaccines typically take years, if not decades, to develop, and some experts have said the administration’s goal is unrealistic.
Dr. Dan Barouch, head of Beth Israel’s Center for Virology and Vaccine Research, which developed the vaccine candidate with Johnson & Johnson, said “it’s more likely” that the vaccine could be rolled out in 2021 than this year, assuming it proves safe and effective.
“The efficacy studies will take a number of months to run,” he said. The vaccine is currently being tested on monkeys, and those results should be available soon, he added.
The first part of the clinical trial in humans will test the vaccine and a placebo on 1,045 healthy adults in two age groups — 18 to 55 years old, and 65 and older. The study will take place in the US and Belgium.
The combined group of volunteers is large enough to generate results for the first and second phases of a clinical trial, Barouch said. He hopes the third, or final, phase of the trial will start in September.
If a coronavirus vaccine could be deployed next year, it would still be far faster than any vaccine ever developed and rolled out. A vaccine for mumps holds the previous record, having been approved by the Food and Drug Administration and licensed by Merck in 1967, four years after researchers began working on it.
Dr. Francis Collins, director of the National Institutes of Health, which is involved in Operation Warp Speed, recently told the Globe that the name reflects technological breakthroughs that have made it possible to develop and test vaccines on humans faster than ever.
Collins said that “if everything goes right,” he believes a COVID-19 vaccine could start being rolled out by year’s end. That would require drug companies to manufacture huge quantities of vaccines before the completion of clinical trials and to discard them if the vaccines don’t pass muster, he said.
Johnson & Johnson said Wednesday that it’s increasing its manufacturing capacity and vowed to supply more than 1 billion doses of the vaccine around the world through 2021 if it passes muster.
One of the other five leading vaccine candidates was developed partly by Cambridge biotech Moderna. That company wants to inject genetic material, called messenger RNA, to instruct cells to make proteins that provoke an immune response.
Moderna’s vaccine entered the first phase of clinical trials in March. Dosing of volunteers in the second phase began on May 29. The company hopes to start the final phase of testing next month.
BARDA is helping to bankroll that effort, too, having pledged up to $483 million in April.
It’s hardly unusual for the federal government to help fund private medical research. But Dr. James Cutrell, an infectious-disease specialist at the University of Texas Southwestern Medical Center in Dallas, said he was unaware of a federal investment in vaccines comparable to what the government is providing in the fight against COVID-19.
“The hope is that if one or more of the vaccines prove to be effective,” said Cutrell, “it will have a payoff in the end” for the economy and the nation’s health that makes the expense worthwhile. Cutrell surveyed the landscape of potential COVID-19 treatments, another fertile area of research, for a paper published in April in the Journal of the American Medical Association.
The three other experimental vaccines that have been identified as among the top candidates of the Trump administration include one developed by Oxford University and AstraZeneca and others by Merck and Pfizer.
Although news reports have sometimes described the rival efforts as a race, Barouch and other scientists say multiple vaccines will have to be approved to end the pandemic. The reason is simple, they say: no single vaccine could be produced in enough quantity to inoculate everyone who wants it.
“We have 7 billion people in the world,” Barouch said. “We actually want multiple vaccines to be successful. If we’re in a race, it’s not a race against each other. It’s a race against the virus and the pandemic.”
Jonathan Saltzman can be reached at email@example.com