NEW YORK (Reuters) - Two adolescent siblings in the United States who signed up for a coronavirus vaccine trial said they did it because they wanted to make their own small contribution to history. Nathan Williams, 17, and his sister Delilah, 12, signed up for the trial after spending months in pandemic isolation. Their mother, Melanie Williams, is a nurse and hospital administrator who works on a ward dealing with COVID-19 patients. “The first thing that came to mind was to be a man for others, primarily just to help everyone else before worrying about my own worries,” said Nathan. He enrolled first in Pfizer Inc’s vaccine research trial at Ochsner Health, based in New Orleans, Louisiana, and was later joined by Delilah. It was totally their decision, said Melanie. “They would watch me come home and meticulously take my shoes off at the door and not bring anything in. And there was also a certain amount of time that we were distanced from each other because there was such an increase in cases in the inpatient arena,” she said. “I left the brochure on the table. I didn’t have any conversations with them about it unless they asked me questions. And then it was sure, why not?” A panel of outside advisers to the U.S. Food and Drug Administration on Thursday voted overwhelmingly to endorse emergency use of the vaccine, developed by Pfizer with Germany’s BioNTech SE. The agency is expected to shortly authorize the shot for a nation that has lost more than 285,000 lives to COVID-19. The principal investigator of the trial for Ochsner Health said children like the Williamses were providing a great public service. ADVERTISEMENT “We have a number of vaccines for the pediatric population,” Dr. Julia Garcia-Diaz said, citing measles, mumps, rubella, chickenpox, pneumonia and the flu. “And all of those vaccines ... had to be tested in children to ensure that it’s safe and efficacious in that population. COVID is no different.” The Williams siblings have experienced no side effects from the trial shots, which could have been vaccine doses or a placebo in the double-blind study. Tracking and reporting their temperatures and any symptoms is a small inconvenience in a global pandemic, they said. “To think that I might be a little part of history is kind of exciting,” said Delilah. “And if I’m just a little person in history, that’s fine with me.”