Johnson & Johnson said Wednesday it has launched the final stage of a single-shot COVID-19 vaccine trial the company hopes will determine if the vaccine is safe and effective by the end of the year or early next year.
The company said 60,000 volunteers are participating in the trial in the U.S., Argentina, Brazil, Chile, Colombia, Mexico, Peru and South Africa.
A number of other coronavirus vaccines in the U.S. and other countries already are in final-stage testing, including those developed by Moderna Inc. and Pfizer Inc.
Many vaccine specialists question whether the U.S. Food and Drug Administration will cut corners to get final approval from President Donald Trump, who has consistently presented a testing timeline that is shorter than experts say is acceptable to fully test the candidates.
President Trump, who has predicted a vaccine will be available by the November 3 presidential election, pushed again Wednesday for accelerated approval of a vaccine, tweeting the FDA "must move quickly!"
U.S. National Institutes of Health Director Dr. Francis Collins told reporters this week, however, that "We want to do everything we can without sacrificing safety or efficacy."
The Washington Post reported Wednesday the FDA, in an effort to promote transparency, will disclose details of a more stringent standard for a vaccine to receive emergency authorization, diminishing the chances of a vaccine approval before election day.
Even if the FDA allowed the emergency use of a vaccine by the end of the year, limited supplies of the vaccine would first be administered to vulnerable groups such as health care workers.
Unlike other experimental coronavirus vaccines in late-stage testing in the U.S., which require two shots, J&J's requires only one. Approval of a single-shot vaccine would simplify distribution of millions of doses compared with leading rivals.