Up to 70% of the
40,000 new HIV infections occurring in the United States
each year are transmitted sexually by adults unaware they
are infected with the virus, Centers for Disease
Control and Prevention officials write in the journal
AIDS. A mathematical model developed at the CDC
shows that 54% to 70% of new U.S. HIV cases are
transmitted through sexual activity by people who are
infected but have not been diagnosed as HIV-positive.
According to the
CDC, there are approximately 1.1 million HIV-positive
Americans, but one quarter of them--more than
250,000--are unaware they have the virus.
Previous studies also have shown that HIV-positive people
who are unaware they are infected are more than twice as
likely to engage in high-risk sexual activities than
HIVers who've been diagnosed, putting their sex
partners at risk of infection.
indicate that the HIV-positive-unaware group contributes
disproportionately to [sexually acquired new HIV] infections
relative to their percentage of the HIV-positive
population in the U.S.A.," the study's authors write.
The data shows the HIV transmission rate among this
group is 3.5 times higher than among HIV-positive people
who've been tested and diagnosed.
CDC officials say
the study reinforces the agency's belief that
encouraging HIV antibody testing is one of the keys in
controlling the U.S. HIV epidemic. Targeted HIV
antibody testing campaigns--including those
aimed at such high-risk groups as gay men,
African-Americans, and injection-drug users--as
well as promoting routine HIV antibody testing in
hospitals, clinics, and doctor's offices are
important steps to take to identify people who are
unaware they're infected and lower transmission
rates, the CDC says. (The Advocate)