The U.S. drugmaker plans to enrol up to 30,000 participants for the study and run it in parallel with a one-dose trial with as many as 60,000 volunteers that began in September.
The UK arm of the study is aiming to recruit 6,000 participants and the rest will join from other countries with a high incidence of COVID-19 cases such as the United States, Belgium, Colombia, France, Germany, the Philippines, South Africa and Spain, it said.
They will be given a first dose of either a placebo or the experimental shot, currently called Ad26COV2, followed by a second dose or placebo 57 days later, said Saul Faust, a professor of paediatric immunology and infectious diseases who is co-leading the trial at University Hospital Southampton.
The trial follows positive interim results from the company’s ongoing early to mid stage clinical study that showed a single dose of its vaccine candidate induced a robust immune response and was generally well-tolerated.
“The study will assess efficacy of the investigational vaccine after both the first and second dose to evaluate protection against the virus and potential incremental benefits for duration of protection with a second dose,” J&J said in a statement.
Rival drugmakers Pfizer and BioNtech said last week that their potential COVID-19 shot showed more than 90% efficacy in interim data from a late-stage trial, boosting hopes that vaccines against the pandemic disease may be ready for use soon.
While the Pfizer-BioNtech vaccine uses a new technology known as messenger RNA, J&J’s uses a cold virus to deliver genetic material from the coronavirus into the body to prompt an immune response.
The platform, called AdVac, is also used in an Ebola vaccine that was approved earlier this year.
“It’s really important that we pursue trials of many different vaccines from many different manufacturers and be able then to ensure the supply both to the UK and global population,” Faust told reporters at a briefing.
Recruitment into the study will complete in March 2021 and the trial will last for 12 months.
