The CDC is expected to update guidelines for Americans with weakened immune systems on Monday. Officials are recommending a shorter wait time to receive a fourth booster dose for those who have received Moderna and Pfizer vaccines. They are also advising people who have gotten the Johnson and Johnson vaccines to seek two booster doses rather than one. Dr. Mark Kline, the chief physician of Children's Hospital New Orleans, joins CBS News' Lana Zak to discuss this and other developments in the COVID-19 crisis.
