By LAURAN NEERGAARD and MIKE STOBBE
AP Medical Writers
Millions more Americans are now eligible for COVID-19 boosters, and they can get a different vaccine than their first shots. A number of factors, including the vaccine you started with and when your last dose was, help determine when you qualify, according to recommendations issued Thursday by the Centers for Disease Control and Prevention. If you started with Pfizer or Moderna and are older than 65 or otherwise at higher risk of infection, you can get a booster after six months. If you started with Johnson & Johnson, you can get a booster after two months, no matter your age.