Updated 17 September 2015

Truvada protects against HIV, but you can still get other STIs

The good news is those who used Truvada to prevent HIV infection remained 100% HIV free. The bad news is half of them picked up other sexually transmitted diseases - because they didn't use condoms.


There is worrisome as well as promising news from data released from a study of the use of Gilead Sciences’ HIV anti-retroviral medication, Truvada for pre-exposure prophylaxis (PrEP) to prevent HIV infection.

Truvada is an anti-viral that can be taken before an individual is exposed to HIV (such as during sex) to prime the body against the  virus and so reduce or prevent infection. It combines two different drugs – tenofovir and emtricitabine – which prevent HIV cells from multiplying.

The combination ARV is already prescribed to HIV-positive patients (including in South Africa) seeking to reduce their body's viral load - the medication suppresses rapid reproduction of viral cells, prolonging life and reducing the chances of passing the disease on to others.

The difference with the FDA's approval (which came after seven years of clinical trials in several countries, including South Africa, the US, Brazil, Uganda, Thailand and Peru) is that it gives HIV-negative individuals (in America) who believe they are at risk of contracting HIV the right to ask their doctor to prescribe Truvada to reduce their chances of becoming infected through lifestyle behaviour.

The study began shortly after the F.D.A. approved the use of Truvada for HIV prevention in mid-2012 and was completed in February of this year.

Dr. Jonathan E. Volk, an epidemiologist for Kaiser Permanente of San Francisco in the USA, and his colleagues monitored a group of men who engaged in risky sexual behavior.

While the men used fewer condoms during this time period, none of them became HIV-positive.

Read: Men on new HIV preventative drug ditching condoms

The good news: of the 657 individuals in the study who actually went on PrEP the were NO HIV infections.

The bad news: after 12 months of PrEP use, 50% of the PrEP users were diagnosed with an STD: 33% with a rectal STI (sexually-transmitted infection), 33% with chlamydia, 28% with gonorrhoea and 5.5% with syphilis.

Equally worrisome, and perhaps reflected in the high incidence of STDs reported: there was a self-reported 41% decrease in condom use, despite the fact that FDA guidelines for use of Truvada as PrEP include continued condom use.

The study, Volk JE et. al. (2015) “… included all adult Kaiser Permanente members evaluated for PrEP from July 2012 (the date of FDA approval) through February 2015.”

“The fact that 50% of the 657 individuals on PrEP in this study contracted a sexually-transmitted infection after one year on PrEP suggests that this population is one of the highest-risk groups, and the most desirable to target for deploying prevention methods like pre-exposure prophylaxis,” said AHF President Michael Weinstein.

“However, the STD incidence, coupled with the reported 41% decrease in condom use - despite FDA ‘black box’ guidelines advising continued use of condoms while on PrEP - suggests the significant limitation of relying solely on a medication-only approach to prevention.”

Limitations in fully analysing the study data released include the fact that no demographic data were released: no racial or ethnic information on study participants, no economic data, nor ages of the individuals.

Concerns about Truvada as pre-exposure prophylaxis use in South Africa, should it be affordable and readily available, include an increase in STIs and the development of osteoporosis and kidney disease as side effects of the drug. There are usually side effects with PrEP use, especially nausea and vomiting and one has to do liver functions tests as well as other blood tests.


- Truvada is used to treat HIV-1 infection in adults and teenagers (12 and older). When used for the treatment of HIV-1 infection, Truvada is always used together with other HIV-1 medicines.
- Truvada is used to help reduce the risk of getting HIV-1 infection when used together with safer sex practices. This use is only for adults who are at a high risk of getting HIV-1. This includes HIV-negative men who have sex with men and who are at high risk of getting infected with HIV-1 through sex, and male-female sex partners when one partner has HIV-1 and the other does not.
- Truvada does not cure HIV-1 infection or AIDS

Read more:

HIV/Aids: Prevention drug trial fails to prevent HIV transmission in women


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Dr Sindisiwe van Zyl qualified at the University of Pretoria before working for an HIV/AIDS NPO in Soweto for many years. She was named one of the Mail & Guardian's Top 200 Young South Africans in 2012.

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