In Brazil, vaccine trial volunteers hope to save lives, not win fame

From doctors weary of seeing patients die to relatives who lost their loved ones, thousands of Brazilians have volunteered for Covid vaccine trials in one of the world's worst-affected countries in the hope their quiet heroism will save lives.

Latin America's largest country has become a major testing ground for vaccines because of the scale of its outbreak, which has seen more than 7.3 million people infected and over 180,000 killed by the coronavirus...