New HIV infections in the United States fell by 12 percent in 2021 compared to 2017, continuing a decline driven by fewer cases in younger people, especially gay and bisexual men, official estimates showed Tuesday.

Infections fell from some 36,500 to 32,100, with the starkest decrease -- 34 percent -- among 13-to-24-year-olds, according to Centers for Disease Control and Prevention (CDC) data.

Men who have sex with men account for an estimated 80 percent of infections in this age group.

"Our nation's HIV prevention efforts continue to move in the right direction," said CDC Director Rochelle Walensky.

Nevertheless, these gains were unequal among different racial groups, with new infections among young white people dropping most, followed by Hispanic and then Black Americans.

One of the greatest indicators of improvement was the rise in access to PrEP (pre-exposure prophylaxis), pills or shots taken to prevent HIV infection from sex or injection drug use.

In 2021, 30 percent of the estimated 1.2 million people who could benefit from PrEP were prescribed it, compared to just 13 percent in 2017.

But the disparities in access were stark when broken down by race. Just 11 percent of the Black population who could benefit from PrEP were prescribed it, compared to 78 percent of the white population.

"Efforts must be accelerated and strengthened for progress to reach all groups faster and equitably," said Walensky.

Annual HIV incidence in the US increased from 20,000 infections in 1981, when the virus was first discovered, to a peak of 130,400 in 1984 and 1985.

The rate stabilized between 1991 to 2007, with approximately 50,000–58,000 infections annually, and then decreased in recent years to 34,800 infections in 2019.