Updated 60 mins ago NBCUniversal Media, LLC Walgreens on Monday said it planned to change the COVID vaccine scheduler on its website following complaints that the pharmacy wasn't adhering to federal health officials' recommended timeline for some second doses. The Centers for Disease Control and Prevention recommends that the two doses for the Pfizer-BioNTech vaccine be spaced three weeks, or 21 days, apart. That timeframe is shorter than the recommended space between the two doses of Moderna's vaccine, which is 28 days or one month. Get the answer to your most-asked COVID vaccine questions on our mobile NBC 5 Chicago app. Download it here for iOS or Android.