Johnson & Johnson on Wednesday announced that it has began its coronavirus vaccine trial involving 60,000 participants, Reuters reported.

The company expects the results of the Phase 3 trial of the single-shot vaccine by the end of the year or the beginning of 2021, Johnson & Johnson’s Chief Scientific Officer Dr Paul Stoffels said in a joint press conference with the United States’ National Institutes of Health and the Donald Trump administration.

“The benefits of a single-shot vaccine are potentially profound in terms of mass immunisation campaigns and global pandemic control,” Dr Dan Barouch, a Harvard vaccine researcher, who assisted in designing the company’s vaccine, told the news agency over a telephonic interview.

The other leading vaccine candidates by Moderna Inc, Pfizer Inc and AstraZeneca require two shots given several weeks apart. This makes it difficult to administer and will also need production of twice as many vaccines needed to inoculate the same number of people.

The vaccine, being developed by Johnson & Johnson, also does not need to be kept in extremely cold temperatures, which was another advantage it had over rival vaccine candidates, Barouch said.

Dr Stoffels also said the company has planned to manufacture 1 billion doses in 2021 and more after that.

The company on Wednesday published a detailed study of its Phase 3 trials amid calls for transparency. The other three leading vaccine candidates have also made these details public in recent weeks.

The third phase trial began after positive results of the vaccine’s first and second clinical trials in Belgium and the United States, Dr Stoffels said, adding that the outcome showed that a single dose could offer sufficient protection for a long time.

The trial will focus on ascertaining whether a single dose could be helpful in severe coronavirus cases and also if it could prevent serious disease that requires medical intervention. It will include patients with both with and without comorbidities, AP reported.

The company said it will focus on diversity and inclusion to include those disproportionately impacted by the coronavirus crisis. In the US, this means there would a significant representation of Hispanics, Blacks, American Indians and Alaskan Native participants.

The trial will be conducted in 215 locations across the US, Brazil, South Africa, Argentina, Mexico, Colombia, Peru and Chile.

The company will later test a booster dose to further improve the immunity offered by the vaccine.

An independent data and safety monitoring board will review the safety and effectiveness of the vaccine at regular intervals. Dr. Francis Collins, director of the National Institutes of Health, said the board does not have any government employees and comprised of “very highly experienced” scientists and statistical experts. The comments come amid concerns that government scientists may be forced to rush the trial to boost Trump’s reelection bid. Presidential elections in the US are scheduled for November 3 and Trump has said that a vaccine would be made available by that time.

The trail will be considered successful if it has an effectiveness rate of 60%.

Johnson & Johnson will also collaborate with the United Kindom on a separate Phase 3 clinical trial for a two-dose inoculation for the vaccine candidate of its pharmaceutical wing, Janssen.

Globally, the coronavirus has infected more than 3.17 crore people and killed 9,75,038, according to Johns Hopkins University. The number of worldwide recoveries is more than 2.18 crore.