The Centers for Disease Control and Prevention have announced that the number of Americans who are infected with HIV has been undercounted for almost a decade. Tomorrow, at the opening day of the international AIDS conference in Mexico City, the newly updated estimates will be presented. It appears that in 2006 there were at least 56,300 new HIV infections, significantly more than the 40,000 estimated in previous years.

HIV infections are very difficult to estimate, due to an array of factors. First of all, it can take many years for an infected person to have symptoms or to otherwise be diagnosed with the infection. To obtain a more accurate prediction, the Centers for Disease Control and Prevention developed a new methodology which might be adopted by other countries as well. For increased accuracy, the CDC combined the blood test with statistical back- calculation methods that estimate the rate of the virus's spread since it was first detected in the United States in the early 1980s.

As expected, gay men are the most affected by new HIV infections. The report will be published this week in the Journal of the American Medication Association. It was previously embargoed for presentation at the XVII International AIDS Conference which begins in Mexico City on Sunday, but the embargo was lifted by JAMA on Saturday morning.

The announcement comes just three days after the Black AIDS Institute has found that the United States spearheads the global response to HIV/AIDS abroad, but neglects problems with the disease at home, especially among black people.