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Truvada as a preventive for HIV

The multiple round, green bumps are sites of assembly and budding of HIV-1 virions under a microscope. (Image: CDC/ C. Goldsmith)

Just last week, the FDA approved the use of Truvada as a pill to reduce the risk of infection in a high risk-population. This news was received with much excitement and caution. In lay terms, Truvada, manufactured by Gilead Sciences is being touted as an HIV vaccine that the world has been waiting for. But is it?

Truvada is a combination of two drugs, Viread and Emtriva, and has been used to treat HIV infection since 2004. It is taken in oral form, once a day. It works by targeting the HIV reverse transcriptase in the body, preventing the virus from multiplying. It is not a cure for an existing infection; it does not eliminate the virus completely. But by limiting how the virus reproduces, it reduces the viral load in the system. Lower viral load means that the immune system is less compromised and there is a lower risk of acquiring infections. Truvada may also increase the CD4 cells in the blood stream. This combination of effects makes the drug a good candidate to control the viral load in the body. Now, the same treatment is being prescribed for reducing the risk of acquiring infections. Clinical studies showed that using Truvada in a high-risk population for HIV infection reduced the risk of infection significantly. This is a very important milestone for couples where one partner is infected and the other is not. 

However, there is a danger in believing that drugs like Truvada can prevent a person from getting infected with HIV. Truvada is recommended as a preventive or a pre-exposure prophylaxis drug only for those individuals who do not have the infection and use safe sex practices. It is not a one-pill substitute for safe-sex practices. Viruses evolve and develop resistance to antiviral drugs. This is why there is no medicine for the common cold. Similarly, the virus that causes HIV can mutate and stop responding to drugs such as Truvada. The protection offered by Truvada lasts only as long as one takes it regularly.

The FDA approval of Truvada as a preventive for HIV is a milestone that must be celebrated. However, public education about the details of how it works is critical to ensure that the rate of HIV infections is reduced over time.