We want to get right to breaking news and race to vaccinate. Big first step for America's children. Moderna set to begin vaccine trials on kids as young as 6 months old. This as 71 million adult Americans have now received the Elise one dose of the vaccine. That's more than 27% of the adult population. More states are opening up vaccine eligibility to anyone over the age of 16. Mississippi joining Alaska. This morning Michigan and Connecticut expected to make this move soon as well and at least 22 states plus Washington, D.C. Are allowing people 16 and older who have high risk medical conditions to get the shot. Let's go to Eva pilgrim at a mass vaccination site in Brooklyn, New York, with more. Good morning, Eva. Reporter: Good morning, Michael. This site is staying very busy doing about 3,000 shots a day. Right now doing mostly older people and those with underlying conditions, but some good news, modern now turning its attention to vaccinating children. This morning, the first step to getting children vaccinated. Just moments ago modern announcing it will start testing its covid vaccine on children as young as 6 months up to 12 years old making them the first U.S. Vaccinemaker to test infants down to 6 months. The company is planning to enroll nearly 7,000 children in the United States and Canada. There will be two parts to the study. The first part is where we will find the appropiate dose of the vaccine in children. Children often need lower doses of vaccines than adults so we want to make sure we find the best dose that increases their immunity, the first age group will start in 6 years to 11 years of age. A second being 2 to 6 years of age and the third being 6 months to 2 years of age. Why are we doing it that way? It's in order to make sure that if we identify a dose that's lower than the adult dose. Reporter: This will be the first vaccine tested on children so young in the U.S. Dr. Steve Plimpton in Phoenix already started enrolling his patients as part of the trial? For that reason we're not only going to benefit the children by getting them vaccinated now we'll protect those around those children, the teachers, the parents and grandparents at home. Reporter: Rachel is enrolling two of her children. I think it's very important because we are exposed to people who might be immunocompromised or haven't had the opportunity to be vaccinated. Reporter: As schools continue to return to in-person learning the CDC is looking into how far they have to be seated after a new study suggested three feet as opposed to six feet may be enough to control the spread of covid in schools with other precautions in place. Pittsburgh public schools returning to in-person school April 6th for the first time in a year after a rapid rollout there of vaccines for teachers. Definitely a game changer for us. We feel really good that a majority of our staff who want the vaccine will be vaccinated. Reporter: And some more good news on the vaccine front, the CDC reporting most people are getting both of their doses within the recommended time period.