MONTGOMERY COUNTY, Pa. - In a space once used as a furniture store in the sprawling King of Prussia Mall, Montgomery County government injected its first Pfizer booster shots Monday.The rollout of boosters in the 800,000 resident county came just days after the Centers for Disease Control and Prevention approved booster shots for millions of Americans 65 years or older, especially vulnerable to the virus and frontline workers.Hank and Margie Hoffman said they came for boosters with their three, young grandkids in mind. "We have grandchildren," said Margie Hoffman. "They can’t get vaccinated yet so we’re always worried about them.