JEFFERSON CITY, Mo. — All adults in Missouri now are eligible to receive a COVID-19 vaccine booster. All adults now can receive a booster shot within six months of their last Pfizer or Moderna dose. People can mix-and-match boosters from any company. Missouri’s health department acted within hours of the Centers for Disease Control and Prevention approving widespread boosters Friday. The government is trying to get ahead of rising coronavirus cases that experts fear could snowball into a winter surge with upcoming holiday travel.