Healthcare workers in Brazil volunteer to test coronavirus vaccines

Healthcare workers in Brazil are on the front line of the coronavirus pandemic in more ways than one, treating patients but also volunteering to test some of the most promising experimental vaccines.

Brazil is the country with the second-highest number of infections and deaths in the pandemic, after the United States, and the virus is still spreading quickly here.

Researchers are planning to run a controlled experiment to see how well the vaccines work.

At least 5,000 volunteers in Brazil are helping test one of the most promising vaccines so far, developed by Oxford University and pharmaceutical company AstraZeneca.

Last week, Brazil also became the first country carrying out Phase 3 trials of Chinese vaccine CoronaVac, developed by pharmaceutical firm Sinovac Biotech.

Phase 3 clinical trials involve large-scale testing on humans, the last step before vaccines seek regulatory approval.

Medical workers play the starring role in testing that vaccine, too.

Volunteers must be between 18 and 55 years old, work in a patient care role and have no underlying medical conditions.

Half the volunteers in the Oxford trial are receiving the vaccine and the other half a placebo. But they will only know which a year from now.

Scientists worldwide are racing to develop and test a vaccine for the virus. There are more than 150 projects so far. But there are no guarantees in the high-stakes race.

Brazil has a deal to make up to 100 million doses of the Oxford vaccine if it proves effective.