COVID cases are rising in all 50 states for the first time since January and several states are reporting breakthrough cases, where vaccinated people are testing positive and even being hospitalized for COVID. There are also concerns about if or when fully vaccinated people will need a third booster shot. CBS News medical contributor Dr. David Agus joins “CBS This Morning” to answer some questions. Each weekday morning, "CBS This Morning" co-hosts Gayle King, Anthony Mason and Tony Dokoupil deliver two hours of original reporting, breaking news and top-level newsmaker interviews in an engaging and informative format that challenges the norm in network morning news programs. Subscribe to “CBS This Morning” on YouTube: https://www.youtube.com/user/CBSThisMorning Watch CBSN live: http://cbsn.ws/1PlLpZ7c​ Download the CBS News app: http://cbsn.ws/1Xb1WC8​ Follow "CBS This Morning" on Instagram: http://bit.ly/1Q7NGnY Like "CBS This Morning" on Facebook: http://on.fb.me/1LhtdvI Follow "CBS This Morning" on Twitter: http://bit.ly/1Xj5W3p Subscribe to our newsletter: http://cbsn.ws/1RqHw7T​ Try Paramount+ free: https://bit.ly/2OiW1kZ For video licensing inquiries, contact: [email protected]