The number of people infected annually with HIV in the United States has fallen dramatically, by 73%, from the darkest of times since the disease first made an appearance 40 years ago, according to a new analysis by U.S. health authorities released Thursday.

But the proportion of infected minority black and Latino people has risen, according to the Centers for Disease Control and Prevention (CDC) on June 5.

"Reductions are due to the decadeslong work of and collaboration with scientists, patients, patient-advocates and communities," said CDC director Rochelle Walensky in a statement.

She reflected on her experience as a young physician in Baltimore at the height of the epidemic when "all I had to give my patients was my outstretched hand and my presence at their bedside," before the mid-1990s when the first highly effective treatments were approved.

There are an estimated 1.2 million people living with human immunodeficiency virus (HIV) in the United States, about 13% of whom are not aware they have the virus.

According to the new report, annual HIV incidence increased from 20,000 infections in 1981 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.

But over time, disparities have widened. The proportion of HIV infections among black people increased from 29% in 1981 to 41% in 2019, and among Hispanic people from 16% to 29% in the same period.

Though there is no cure or vaccine, HIV medicine called antiretroviral therapy (ART) now exists that manages the virus and prevents it from causing AIDS (acquired immunodeficiency syndrome).

Drugs called Pre-Exposure Prophylaxis (PrEP) and Post-Exposure Prophylaxis (PEP) are also available to prevent HIV transmission either before or after risky exposure, respectively.

But while PrEP is 99% effective, only 23% of people who could benefit from it were using it in 2019.

This included 63% of white people, but only 8% of black people and 14% of Hispanics.

Routine screening and rapid tests have also helped drive the overall fall.

"Prevention tools are increasingly effective, but they need to reach the populations most affected," the report said.

Over half of new HIV infections are in the southern U.S., where attitudes are less open towards sexual health.