KSAT Q&A: Dr. Berggren discusses teen vaccinations, when you should still keep your mask handy These tips come after the CDC released new guidelines on face masks for those who are fully vaccinated. Tags: The following are a few takeaways from the conversation on Thursday night. Dr. Berggren believes the new CDC mask guidelines should be an incentive to get vaccinated. Don’t want to wear a mask? Get a shot. 17 million people are aged 12-17, a significant part of the population to get immunized. The vaccine is safe for adolescents. No evidence this vaccine causes people to become infertile or sterile.