Arianna Cavalcante, 28, a dental surgeon, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 09, 2020. "I decided to take part in the trials because there was a light at the end of the tunnel for this new disease that scares all of us … I lose patients every day. It's desperate. It's terrifying. So I believe that every opportunity to help is valid," Cavalcante said. "I think that in the future, volunteers will not be remembered. Just like today there are several vaccines and no one remembers the volunteers who ever took part in the tests. But I don't mind, I don't mind not being remembered. I think that having the vaccine and saving people for me is the most important thing." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES