WASHINGTON — Dr. Anthony Fauci says vaccinated Americans would "not necessarily" need to get booster shots this fall for further protection from COVID-19.

Fauci, the nation's leading infectious disease expert, told CBS "This Morning" on Friday that scientists would be tracking data on the virus and possible variants. He says it was still "possible" an additional shot would be needed later this year to ward off possible infection.

Fauci also urged Americans to continue to follow CDC guidelines. He stressed those who haven't been fully vaccinated still need to wear masks even if they are largely spending time with people who have been inoculated.

The doctor also says those attending indoor sporting events, like the NBA playoffs starting this week, should follow the masking policies of the arena.