JULY 1999 

Is AIDS officially a rare disease in US?

THE NATIONAL ORGANIZATION for Rare Disorders (NORD)'s website <www.rarediseases.org> includes information about AIDS and describes the official definition of a rare disease as any that currently affects fewer than 200,000 Americans.

According to the CDC's latest available AIDS data, the HIV/AIDS Surveillance 1998 Year-end Report (10:2, available at www.cdc.gov or 800-458-5231), the number of "persons living with AIDS" -- what it also calls "AIDS prevalence" (page 25) -- was 270,841 in 1997, the latest year for which it offers statistics.

Although that figure barely lies above 200,000, it includes the many AIDS cases (including a majority of initial diagnoses) that involve symptom-free HIV-positive people who simply have low CD4 immune cell counts. And each year through 1994 -- after ten years of loud official hysteria about a raging epidemic -- AIDS prevalence fell bellow 200,000. It didn't even exceed 100,000 until 1991 (1997 Mid-year Report ). Only the 1993 AIDS redefinition, expanded to include illness-free people with low CD4 counts, nudged AIDS prevalence over the 200,000 mark. I couldn't find any data that estimated the fraction of current AIDS patients who lack any clinical illness.

NORD vice-president, Maria Harden (203-746-6518 <orphan @rarediseases.org>) said NORD doesn't keep a list of which diseases qualify as rare because the list changes so often.

Some rare diseases eventually break the 200,000 threshold, she said, and some non-rare diseases may get divided into sub-categories that qualify as rare in order to qualify for the Orphan Drug Act. That law gives drug companies 50 cents for every dollar they spend developing drug treatments for rare diseases.

So who keeps the list of diseases regarded as rare? The National Institutes of Health's Office of Rare Diseases, she said. Its director, Steve Groft (301-402-4336, <sg18b@nih.gov>, www.rarediseases.info.nih. gov), confirmed NORD's definition of a rare disease. "It [AIDS] did at one time qualify," he said. "However, once the [low] T-cell count [was introduced as an AIDS condition] the number of AIDS cases went over the 200,000 threshold figure. Each individual opportunistic infection associated with HIV/AIDS, though, still qualifies."

But what about the 270,084 figure minus anybody who merely has a low CD4 count but no clinical illness? Would symptomatic AIDS today qualify as rare? Neither he nor anybody to whom he referred me knew how many of the 270,084 living American AIDS patients had low CD4 counts as their only AIDS condition. As far as I can tell, nobody has compiled that statistic. All we know is that according to the CDC HIV/AIDS Surveillance Reports , each year since 1993 most new diagnoses involved people with low CD4 counts as their only AIDS condition. Groft agreed that if only symptomatic patients were considered, AIDS might still qualify as a rare disease, and that in any case, the 270,084 figure is pretty close to rare anyway.

I asked if he thought this contradicts the official message so successfully received by Americans that "everyone is at risk" and that AIDS is a major health threat. All he would say is that, "I don't think we can be cautious enough over one source of HIV, that being contaminated blood."

-- Paul Philpott