Using a survey of high school students ages 14 to 18, the Centers for Disease Control and Prevention (CDC) found that only 22 percent of teens having sex are getting tested for HIV, Reuters reports. Almost half of American HIV-positive young adults are unaware of their status.

Released on June 25 in anticipation of National HIV Testing Day, June 27, the report also found the following: Older students were more likely to get tested than younger students; girls were more likely to get tested than boys; and HIV testing was more common among students who had been taught about HIV/AIDS in school.

“At the end of 2006, an estimated 48 percent of adolescents and young adults infected with HIV were unaware of their infection, representing missed opportunities for diagnosis, treatment and reduction in the number of new HIV transmissions,” the CDC said.