Jane Cristina Dias Alves, 43, a nurse, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 11, 2020. Alves has a daughter and lives with the parents and with the grandmother. "Two nurses on my team, who are close to me and we talk every day, had COVID-19 and were hospitalized here in the ICU. It was something that moved us all. That influenced my decision – both the fear and also the conviction to join the trial. It strengthened my desire to take part in the trial. To know how much we can make the difference. Having a colleague next to you ill with the virus, taking care of him, knowing he can get worse and even lose his life – that moves something inside you," she said. "People look at me and say, 'Really, you are a volunteer? But you are so young. Isn't that risky?' And I try to put them at ease. We can also be an inspiration to people. To do this, to be a volunteer, it's important to understand your role in society." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. TPX IMAGES OF THE DAY 

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 

Sergio Aparecido Cleto, 46, a nurse, a volunteer in COVID-19 vaccine trial for Sinovac, poses for a photograph in Sao Paulo, Brazil, December 10, 2020. Cleto is married, has two sons and his wife is pregnant. "I decided to take part in the trial because of my sense of commitment – not only my professional commitment as a nurse, whose essence is to take care, but also a personal commitment, a human commitment. This is about being able to help to find a cure for this disease which scares us so much," he said. Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

Monica Aparecida Calazans, 54, a nurse, a volunteer in COVID-19 vaccine trial for Sinovac, poses for a photograph in Sao Paulo, Brazil, December 10, 2020. Calazans who has one son, said: "My brother, who is 47 years old had COVID-19, had a severe form of the disease. We even thought we would lose him. And then I thought, 'If I don't take the vaccine, we will never know if it works or not.' For him, but for everyone else too, I had the drive to take part in the trial." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

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 

Morgana de Menezes Maia, 24, a dental surgeon, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 09, 2020. "I have been working with COVID-19 patients since the beginning of the year … I've learned how important it is to stay close to our family and people we love – what a difference that makes, both in your personal and professional life. I think I matured during this year. Facing all this has made me more independent. I've always had (my parents) by my side, but I had to face this all alone, at work and everywhere else. I think it was a year that matured a lot," Menezes Maia said. "The hardest part was to face this period without knowing when it is going to be over, without knowing if the vaccine will really be here next year … The pandemic affected the whole world. Everyone felt the effects of quarantine, isolation, the disease. Many people lost their loved ones, friends. Being able to volunteer is unique. There aren't a lot of us who are part of this moment that will be remembered. Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

Antonia da Silva Cruz Santos, 48, a nurse, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 08, 2020. "The first days after I took (the vaccine), I had a few symptoms – shivers and pain in my body. I had some bad thoughts, like what if I were intubated, I was always afraid of that … My daughter was desperate. She said 'Mom, you are crazy.' I said, 'No, crazy would be not to take it.'," Santos said. Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

Keller de Martini, 55, a dental surgeon, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 07, 2020. Martini who is married and has two sons, said: "I think when we look to this period, one legacy will be how everyone – the scientists, the health workers, everyone – fought to stop the loss of lives to COVID-19. It will be a very important moment to remember. Children will study this in school to understand the fight and difficulties we lived. And this legacy that will remain for everyone." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

Denise Abranches, 47, the first volunteer in COVID-19 vaccine trial in Brazil and the first volunteer outside Britain to receive the trial vaccine from AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 07, 2020. Abranches is a dental surgeon and coordinator of dentistry at Sao Paulo hospital. "I witnessed many lonely deaths here: patients who could not say goodbye to their relatives; relatives who could not say goodbye to their loved ones. When the vaccine trial came, I joined immediately. I never hesitated," she said. "This global effort of volunteers in search of a vaccine will be remembered and will go down in history. Everything that has happened – the deaths, the whole world's effort to find a vaccine, the researchers, the scientists. And the gesture of love from volunteers. That's how I'd like to be remembered." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES 

Ana Marcela Rojas Fonseca Hial, 49, a doctor, a volunteer in COVID-19 vaccine trial for AstraZeneca, poses for a photograph in Sao Paulo, Brazil, December 10, 2020. Hial who has one son said: "The hardest thing in the pandemic has been seeing whole families sick and the sense of powerlessness that you can't resolve the situation … This global push to resolve the situation is a very special moment." Picture taken with a slow shutter speed. REUTERS/Amanda Perobelli SEARCH "PEROBELLI VACCINE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES