Chances of contracting the HIV virus are 1 in 900 sex acts, study says

There is a 1 in 900 chance of contracting HIV in any one sexual act with an infected person, but the statistic is highly variable.

The study, which focused on almost 4,000 heterosexual couples in Sub-Saharan Africa, found that although an uninfected partner had an average 1 in 900 chance of contracting HIV in any given sexual act, that chance was highly influenced by several factors, making it either far more likely or far less likely than the stated average.

This is one of the cases in which a statistical average may be highly misleading. The average is calculated from an enormous range of chances, some which may be as high as one in ten, or even higher. In short, the one in 900 statistic should not lull vulnerable individuals into a false sense of security.

The two most substantial factors influencing the probability of contracting HIV were found to be the amount of virus in the blood of the infected individual and the use of a condom. Other factors predisposing infection were absence of circumcision in men and genital herpes infection in women.

The study found that the amount of virus in the blood is the single most important factor: for every tenfold increase in the concentration, there is about a threefold increase in the risk of transmission during a single sexual act. Persons with very high concentrations, as occurs in those who acquired the infection very recently, may need to have sex only 10 times to transmit the virus, said study researcher James Hughes, of the University of Washington in Seattle.

Hughes affirmed that the “average” can be quite deceptive.

The new findings reinforce those of previous research which affirms that HIV infection rates can be reduced up to 96 percent by reducing the amount of circulating virus in the blood, as can be accomplished through anti-retroviral drugs.

The study also found a 78 percent reduction of transmission rate through the use of condoms, though researchers believe the rate is actually higher and that study participants overstated their purported use of condoms. Male circumcision helped in reducing transmission by 47 percent.

The study may have limited applicability outside of Africa because the couples studied were heterosexual and long-term. Researchers suspect that among individuals in this particular demographic, the couples might have some biological protection against transmission.

The study followed the couples over a two-year period, during which eighty-six HIV transmissions occurred. The uninfected partners were tested periodically to see whether they had acquired HIV, and researchers used DNA testing to ascertain whether the new infections came from the individual’s partner or elsewhere.

Men were twice as likely to transmit the infection to women as women were to men. This may be due to higher concentrations of the virus among men, and a higher incidence of genital herpes among women.

Dr. Myron Cohen, a professor of medicine, microbiology, immunology and public health at the University of North Carolina at Chapel Hill, who was not involved in the work, said that “the true estimation [of transmission] might be higher if you were studying different kinds of people," such as homosexual male partners.

Source

Image Source: Wikimedia Commons

Comment and add to the story without registration, but keep the comments meaningful please. Links are not accepted.