The Centers for Disease Control and Prevention (CDC) estimates that 1.2 million U.S. residents were living with HIV in 2011, with 86 percent of them diagnosed, 40 percent engaged in medical care for the virus, 37 percent prescribed antiretrovirals (ARVs) and 30 percent virally suppressed. (These stats are collectively known as the treatment cascade.)

A new study suggests the HIV epidemic is actually in much better shape. Researchers at the New York City Department of Health and Mental Hygiene recently used HIV laboratory reporting to estimate HIV prevalence in their city and relied upon previously published data to construct a revised HIV treatment cascade.

These researchers estimated that the true number of people living with the virus in the United States in 2011 was just 819,200, with 86 percent of them diagnosed, 72 percent engaged in medical care, 68 percent on ARVs and 55 percent virally suppressed. While the study’s authors state that they did not intend to make an official estimate of the size of the HIV population, they feel their statistical methods suggest that the CDC’s own estimate is too high.

“I think this new analysis is just the kind of thing we need to inject some critical thinking into the question of whether we are really getting the best information that we can [with regard to the treatment cascade]”, says Jennifer Kates, PhD, director of global health and HIV policy at the Kaiser Family Foundation.

Meanwhile, recent CDC research has suggested that viral suppression rates have been steadily increasing among people in care for the virus in the United States.