The delta Covid-19 variant now accounts for more than 50 percent of new cases across the country, especially in states with low vaccination rates. NBC News medical contributor, Dr. Natalie Azar, breaks down how health officials are reacting to the surge in cases and whether restrictions could be reintroduced in the fall and winter.  » Subscribe to NBC News: http://nbcnews.to/SubscribeToNBC » Watch more NBC video: http://bit.ly/MoreNBCNews NBC News Digital is a collection of innovative and powerful news brands that deliver compelling, diverse and engaging news stories. NBC News Digital features NBCNews.com, MSNBC.com, TODAY.com, Nightly News, Meet the Press, Dateline, and the existing apps and digital extensions of these respective properties. We deliver the best in breaking news, live video coverage, original journalism and segments from your favorite NBC News Shows. Connect with NBC News Online! NBC News App: https://smart.link/5d0cd9df61b80 Breaking News Alerts: https://link.nbcnews.com/join/5cj/breaking-news-signup?cid=sm_npd_nn_yt_bn-clip_190621 Visit NBCNews.Com: http://nbcnews.to/ReadNBC Find NBC News on Facebook: http://nbcnews.to/LikeNBC Follow NBC News on Twitter: http://nbcnews.to/FollowNBC Follow NBC News on Instagram: http://nbcnews.to/InstaNBC #DeltaVariant #Coronavirus #Covid