A volunteer in a clinical trial of a COVID-19 vaccine in Sao Paulo, Brazil, has died, according to the country’s health authority. The 28-year-old man did not receive the vaccine, according to Bloomberg News. The Federal University of Sao Paulo was helping coordinate the phase 3 clinical trials for the vaccine developed by AstraZeneca and Oxford University. The drug’s trial in the U.S. has been on hold for more than a month. Testing of the vaccine will continue in the U.K. and Brazil, but further information was not immediately available.