The chaotic response to the coronavirus in Brazil, where it has killed more than 105,000 people, made the country’s experience a cautionary tale that many around the world have watched with alarm.
But as the country’s caseload soared, vaccine researchers saw a unique opportunity.
With sustained widespread contagion, a deep bench of immunization experts, a robust medical manufacturing infrastructure and thousands of vaccine trial volunteers, Brazil has emerged as a potentially vital player in the global scramble to end the pandemic.