https://apnews.com/7769bb38ab843ad1661aaf89c39244a5 > Millions more Americans just became eligible for COVID-19 boosters but figuring out who's eligible and when can be confusing — and adding to the challenge is that this time around, people can get a different type of vaccine for that extra dose. > A number of factors, including the vaccine you started with and when your last dose was, help determine when you qualify. Just like the initial shots, boosters are free and will be available at pharmacies, doctor offices and clinics.