been steadily rising since this summer. in october the fda authorized a smaller dose of the pfizer vaccine for children ages 5 through 11. that group remains the least vaccinated. vaccination is a key to controlling this pandemic, but we're learning how how long it can last. protection against severe disease does remain high. the cdc has expanded the recommendation for all adults over 18 to get a booster shot, six months after the pfizer and moderna vaccines and two months after the johnson & johnson one. >> we know they're safe and they're highly effective in bringing very, very high up the optimization of your protection. over the last two years there have been thousands of variants, with a handful of them becoming variants of concern. still vaccination, masking,