The number of new HIV cases in the United States has leveled off at about 50,000 a year, but one important group is defying the trend: those ages 13 to 24

The CDC says that about 1,000 new infections a month occur in the age group, and most of those infected (60%) have no idea. Young black men are driving the increase, accounting for 45% of the new cases. Most infections occur in men having sex with other men.