NBC News medical contributor Dr. Vin Gupta discusses new CDC guidelines that state masks will not only prevent the spread of COVID-19 but will also protect the mask wearer from contracting the virus. “We know that if there is 95% masking broadly in the United States, we would effectively end this pandemic, we wouldn’t have to worry about a vaccine, and we would save 100,000 lives by Jan. 31 of 2021,” said Dr. Gupta.