The AIDS epidemic has cut a far wider path across America than previously believed, federal disease trackers reported yesterday, with the number of new infections since the late 1990s now thought to be 40 percent higher than earlier projections.
For more than a decade, the US Centers for Disease Control and Prevention had estimated that 40,000 Americans a year become infected with HIV, the virus that causes AIDS. But advances in blood-testing methods combined with closer tracking of new cases allowed the health agency to determine that the actual figure is closer to 56,000 infections a year.
The revised estimate of HIV's toll in the United States had been the subject of considerable speculation among AIDS specialists as the CDC spent more than a year developing its new, more exact portrait of the epidemic, drawing criticism from activists who said they too long.
The recognition that roughly 160,000 more people may have contracted HIV since the late 1990s holds profound consequences, medically, economically, and socially, according to physicians, policy makers, and AIDS service organizations. That is especially true at a time when scientists are despondent over recent high-profile failures of vaccines and other approaches to preventing infections.
"It's going to require a whole lot more in resources to be able to provide appropriate medical care for this additional 160,000 people," said Dr. Daniel R. Kuritzkes, director of AIDS research at Brigham and Women's Hospital. "I hope these new estimates do serve as a wake-up call."
The CDC used the backdrop of the International AIDS Conference in Mexico City to release its much-anticipated report, which confirmed that the burden of HIV is borne disproportionately by gay and bisexual men as well as African-Americans. A CDC spokeswoman said the agency had not calculated the total number of Americans infected with HIV as part of this report, although that figure is being updated; earlier projections placed that number as high as 1.2 million.
The official who presented the study, Dr. Kevin Fenton, stressed that while the estimated figures are higher, they remained relatively stable at that level for a decade.
"The fact remains there are too many people becoming infected with HIV every year," said Fenton, director of the CDC center that includes efforts to track and prevent HIV.
At the dawn of the epidemic, disease specialists focused on counting AIDS cases for a simple reason: AIDS progressed so swiftly that doctors believed that counting AIDS cases was the best reflection of the disease's movement.
But the arrival of potent drug cocktails has revolutionized the course of HIV in the developed world and, increasingly, in sub-Saharan Africa, where the majority of the world's AIDS patients lives. Those medications have transformed AIDS from an almost-certain death sentence into more of a chronic, controlled disease.
That made counting new cases of HIV - the virus that can ultimately result in fully advanced AIDS - more important than ever. But, until recently, federal disease specialists relied on statistical guesswork to make their estimates.
"Many of us felt for some time that the methodology originally used was flawed," said Dr. Stephen L. Boswell, president of Fenway Community Health, a Boston treatment and research center that specializes in taking care of patients infected with HIV.
Some AIDS service organizations were even sharper in the criticism of the federal health agency: "From our perspective, this is certainly indicative of poor planning and poor administration of things going on at CDC," said Nathan Schaefer, director of public policy at Gay Men's Health Crisis, a major provider of AIDS education and prevention services in New York.
The CDC a few years ago embarked on a major campaign to change the way it tracked HIV. Central to that was a mandate that states adopt a standard method for counting and reporting cases called names-based reporting.
That meant that physicians had to confidentially report the names of patients infected with HIV, a system designed to prevent counting the same patient more than once; previously, states had relied on a variety of approaches.
At the same time, sophisticated new blood tests were introduced that can, essentially, determine when a patient became infected with HIV, providing more important clues about the current spread of the virus.
"This means that CDC's ability to measure the true scope of the epidemic has improved," said Kevin Cranston, director of the HIV/AIDS Bureau at the Massachusetts Department of Public Health. "And that is crucially important."
For one thing, Fenton said, being able to develop a real-time snapshot of HIV infections will allow disease specialists to know whether their strategies for preventing new cases are working and where prevention campaigns need to be retooled.
The estimate released yesterday, which focused most extensively on HIV infections in 2006 but also provided estimates for earlier years, was a national extrapolation from data from 22 states.. Massachusetts was not included among the 22 because it did not order names-based reporting until 2007.
Cranston said that historically, Massachusetts has estimated that 900 to 1,000 residents contract HIV each year. But reports from 2006, he said, show that the new infections may be declining in the state.
Still, he said, because patients are living for decades with the disease - and dying from it at a far lower rate than a decade ago - "there have never been more people living with HIV in the United States or in Massachusetts, and there will be more tomorrow because of our success in keeping people alive and well," said Cranston. As many as 25,000 Bay Staters may be HIV-positive, he added.
Even before the release of the report showing that the national epidemic is worse than previously acknowledged, clinics and medical practices that treat HIV patients complained that government aid was not keeping pace with the escalating cost of caring for people whose drug bills can easily top $10,000 a year.
And state and local health officials complain that not nearly enough is spent on prevention, with only 4 percent of federal HIV spending devoted to stopping the spread of the virus.
"The new estimates are quite staggering," said Mark Cloutier, chief executive officer of the San Francisco AIDS Foundation, which provides services in the Bay Area. "It's only going to get worse if we don't match what we're seeing with funding and evidence-based prevention programs.
"Otherwise, we're going to lose the battle."
Stephen Smith can be reached at email@example.com.