Although the number of people living with HIV has
increased in the United States over time,
the rate at which an infected person passes the virus on to
an uninfected person has dropped
significantly since the peak of the epidemic, according to
a study by researchers at the Johns Hopkins
Bloomberg School of Public Health and the Centers for
Disease Control and Prevention.
Researchers found the rate of transmission has dropped
88 percent since 1984 and 33 percent
since 1997. The study will be published in JAIDS:
Journal of Acquired Immune Deficiency Syndromes
and is available on the journal's Web site in advance of
"For every 100 persons living with HIV today, five or
fewer will transmit the virus to an
uninfected person in a given year," said David Holtgrave,
lead author of the study and chair of the
Bloomberg School's Department of
Health, Behavior and Society. "In other words, 95
percent or more of those living with HIV do not transmit
the virus to others, which indicates that prevention
are having a real impact."
Holtgrave and his colleagues based their analysis on
the CDC's latest HIV incidence data.
According to the study, the annual transmission rate in
1984 was 44 per 100 persons with HIV. The
annual rate dropped to 6.6 per 100 persons by the early
1990s. The transmission rate rose slightly to
7.5 per 100 persons in 1997, when new antiretroviral
therapies were first introduced; researchers
said these therapies might have led some persons at risk
for HIV to disregard prevention measures.
By 2006, the transmission rate dropped to just below five
"The declines reflect the success of prevention
efforts across the nation," said Richard
Wolitski, study co-author and acting director of the CDC's
Division of HIV/AIDS Prevention.
"However, despite this success, we cannot forget that new
HIV infections are increasing among gay
and bisexual men and that African-Americans and Hispanics
continue to experience disproportionate
and unacceptably high rates of HIV and AIDS. The fight
against HIV is far from over."
The research was not funded by a specific grant.