The only sure way to prevent HIV transmission is to not engage in behavior that puts you at risk. That means abstinence from sexual activity or living in a committed, monogamous relationship with a partner who is free from HIV; as well as not sharing needles or any other drug paraphernalia.

When the modes of transmission were first understood to be largely sexual in nature, many felt the promotion of condoms would eliminate virus transmission from one individual to another. Various studies indicate, however, that condoms offer a similar level of protection for HIV disease as they do in preventing pregnancy. In other words, while they reduce risk, they do not eliminate it.

A prominent study done by Dr. Margaret Fischl showed that over a 12- to 18-month period, couples that were discordant (one HIV-positive and one HIV-negative) who exclusively used condoms, infected their partners 17 percent of the time. Similar couples that abstained from intimate sexual contact had no viral transmission, and viral transmission took place in 81 percent of those that used no barrier device. This study was done with individuals who knew their HIV status. Fully 60 percent of people today who are infected do not know they are infected and, consequently, are unknowingly and unintentionally infecting others.

Ultimately, the most effective way to break the virus' chain of transmission will not be condoms but a modification of sexual behavior in which having more than one sexual partner is strongly discouraged.