The study will involve 60,000 volunteers from Brazil, Chile, Colombia, Peru, Argentina and Mexico and will be coordinated by J&J's pharmaceutical unit Janssen and local academic centers.

The company told Reuters it was waiting for regulatory approval in Chile, Argentina and Mexico.

"This multilateral collaboration...demonstrates the progress and commitment of collective efforts to find solutions for the COVID-19 pandemic," it said in a statement.

Miguel O'Ryan of the University of Chile's School of Medicine, which will host the J&J trial, said the parameters were still being worked out but his team was prepared to recruit up to 1,000 volunteers for trials funded by the vaccine developers.

"From our point of view, as soon as we have the vaccine available, within three weeks we should be able to vaccinate the first volunteer," he said.

The Chilean Health Ministry did not respond to a request for comment.

The J&J trial is one of several likely to take place in Chile. Sinovac - whose trial is funded by the Chilean government, local industry and academia - is due to launch a search for volunteers shortly, while the country is also in talks with CanSino Biologics Inc, AstraZeneca Plc and Moderna Inc.

In Peru, Carlos Castillo, the Ministry of Health's chief vaccines adviser, told Reuters that J&J was picking research centers and the trial would get under way in mid-September.

On Wednesday the Chinese firm Sinopharm began recruiting for 6,000 volunteers for its own vaccine trials. Peru President Martin Vizcarra has said he also hopes to confirm by the end of August trials of the AstraZeneca/Oxford University vaccine.

J&J's prototype uses "viral vectors" to generate immune responses, similar to the approach taken by Oxford's vaccine developers and China's CanSino.

Brazil, Chile, Peru, Argentina, Mexico and Colombia are the six Latin nations with the highest number of confirmed coronavirus cases. Vaccine developers look for areas with high rates of active transmission and infection because that renders it easier to get dependable trial results.

J&J's head of vaccines previously told Reuters the company aimed to produce 1 billion doses of a potential vaccine next year.