The U.S.-based pharmaceutical giant, which is working alongside German drugmaker BioNTech, said the first human participants in the United States have been dosed with the potential vaccine, BNT162. They began human trials of the experimental vaccine late last month in Germany.
"With our unique and robust clinical study program underway, starting in Europe and now the U.S., we look forward to advancing quickly and collaboratively with our partners at BioNTech and regulatory authorities to bring a safe and efficacious vaccine to the patients who need it most," Pfizer Chairman and CEO Albert Bourla said in a statement.
"The short, less than four-month time frame in which we've been able to move from preclinical studies to human testing, is extraordinary," he added.
The experimental vaccine contains genetic material called messenger RNA, or mRNA. The mRNA is a genetic code that tells cells what to build — in this case, an antigen that may induce an immune response for the virus.
The trial will test the experimental vaccine on adults ages 18 to 55 in the first stage before moving on to older groups, the company said, adding it hopes to test up to 360 people.
There are no FDA-approved therapies to treat Covid-19, and drugmakers are racing to produce a vaccine, which U.S. health officials say is expected to take at least 12 to 18 months.
The effort by Pfizer and BioNTech is one of several working on a potential vaccine to prevent Covid-19, which has sickened more than 3.5 million people worldwide and has killed at least 247,752 as of Monday night, according to data compiled by Johns Hopkins University. There were more than 100 vaccines in development globally as of April 30, according to the World Health Organization, with at least eight vaccine candidates already in human trials.
Hopes to get a vaccine to market are high, but scientists are setting expectations low for how quickly it can happen. Developing, testing and reviewing any potential vaccine is a long, complex and expensive endeavor that could take years, global health experts say.
Biotech firm Moderna, in partnership with the National Institutes of Health, began the first human trial testing for a potential vaccine in March.
Johnson & Johnson said it is aiming to produce 600 million to 900 million doses of its potential coronavirus vaccine by the end of the first quarter of 2021 if human trials scheduled to begin in September go as planned.
Pfizer hopes to produce "millions" of vaccines by the end of this year, the company's chief scientific officer, Dr. Mikael Dolsten, told CNBC last month. The company said Tuesday it expects to increase to "hundreds of millions" of doses next year.
Sites currently dosing participants include NYU Grossman School of Medicine and the University of Maryland School of Medicine, Pfizer said. The University of Rochester Medical Center, Rochester Regional Health and Cincinnati Children's Hospital Medical Center will "begin enrollment shortly," the company said.
Upon regulatory approval, Pfizer and BioNTech will work jointly to commercialize the vaccine worldwide.