With more than 144 million adults now fully vaccinated against Covid-19, Pfizer is moving ahead with low-dose trials in children under 12-years-old and could begin mass vaccinations of kids in the fall. NBC News’ Maura Barrett is in Jefferson, Louisiana, where doctors are testing whether the vaccine is safe for children.  » Subscribe to TODAY: http://on.today.com/SubscribeToTODAY » Watch the latest from TODAY: http://bit.ly/LatestTODAY About: TODAY brings you the latest headlines and expert tips on money, health and parenting. We wake up every morning to give you and your family all you need to start your day. If it matters to you, it matters to us. We are in the people business. Subscribe to our channel for exclusive TODAY archival footage & our original web series. Connect with TODAY Online! Visit TODAY's Website: http://on.today.com/ReadTODAY Find TODAY on Facebook: http://on.today.com/LikeTODAY Follow TODAY on Twitter: http://on.today.com/FollowTODAY Follow TODAY on Instagram: http://on.today.com/InstaTODAY #Pfizer #Vaccines #Coronavirus