The United States is launching a new distribution program for Covid-19 booster shots — and if you're one of the nearly 14 million people who got the one-shot Johnson & Johnson vaccine, you probably have a few questions.

On Wednesday, top U.S. health officials — including CDC Director Dr. Rochelle Walensky and White House chief medical advisor Dr. Anthony Fauci — said booster shots will become available next month, citing data suggesting that vaccine-induced protection from the virus wanes over time. People who received two doses of an mRNA vaccine from Pfizer or Moderna are now eligible for a booster shot eight months after their last dose. Notably absent: a recommendation for anyone who received the J&J vaccine.