COVID-19 trial vaccine volunteer Luiz Augusto Menegazzo, 65, a doctor, a volunteer in COVID-19 vaccine trial for Sinovac, poses for a photograph in Sao Paulo, Brazil, December 04, 2020. Menegazzo who is married and has two sons, said: "I think we will remember this moment as a great moment of learning. A chance for humanity to learn, to be more humane, to live better, and for the government to take a closer look at its people." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. HEALTH-CORONAVIRUS/GEN-Z