Science has made great strides in understanding, treating, and preventing HIV/AIDS. We can hope for an AIDS vaccine, but meanwhile there is a pill that can markedly reduce the risk of becoming infected.
Truvada: a good alternative while we wait for an AIDS vaccine. Image taken from the NIAID flickr page with a Creative Commons license.
The story of HIV/AIDS illustrates the value of science-based medicine. The first cases of AIDS were reported in 1981. By 1983, only two years later, two different research groups under Luc Montagnier and Robert Gallo had independently identified the cause of AIDS: a retrovirus that is now known as human immunodeficiency virus (HIV). Treatment with anti-retroviral drugs originally required multiple drugs given on a complicated schedule with many doses a day; they often caused unwanted side effects. Today patients can be treated with a once-a-day combination pill using lower doses that cause fewer side effects. AIDS was once considered a death sentence, but today it has become a chronic treatable disease with near-normal life expectancy. A 20-year-old with HIV can expect to live to 78.
Research is ongoing, but as yet there is no vaccine available. While we wait for a vaccine, there is a viable alternative that not everyone is aware of. People who are at high risk of becoming infected with HIV can take a daily pill that will markedly reduce their chances of infection. It’s expensive; it’s not perfect; but when we educate people about safe sex practices, shouldn’t we also educate them about the possibility of pre-exposure prophylaxis (PrEP)? I wonder if the average American even realizes there is such a thing.
What is Truvada?
Truvada is the most well-known of several brand names for a fixed-dose combination of two antiretroviral drugs: tenofovir disoproxil and emtricitabine. It is a pill taken once daily. It was approved in 2004 and is on the World Health Organization’s list of essential medicines. Wholesale cost in the developing world is US$6.06 to $7.44 a month; in the US it costs $1,415.00 per month. Why?
Is it effective?
A Cochrane systematic review estimated that PrEP could reduce the risk of infection by as much as 50%.
These four clinical trials are listed on the CDC website:
- A 2010 study published in The New England Journal of Medicine found a 44% reduction in the rate of HIV infection with PrEP compared to placebo in men who have sex with men (MSM) . Detectable blood levels were strongly correlated with the prophylactic effect.
- A placebo-controlled study in 2012 in Botswana found PrEP was 62.2% efficacious in preventing infection in heterosexual adults.
- Another 2012 study in Kenya and Uganda looked at heterosexual couples where one partner was HIV-positive. The combination of tenofovir and emtricitabine reduced the risk of infection by 75% and tenofovir alone reduced the risk by 67%.
- A 2013 randomized, double blind, placebo-controlled phase 3 study of HIV-negative adults in Bangkok, Thailand found a 9% reduction in infections in patients who used injection drugs.
Is it safe?
The most common side effects in HIV-negative patients are headache, abdominal pain and weight loss. The package insert carries numerous warnings. It can cause liver complications including severe hepatomegaly with steatosis. There is a risk of drug resistance if it is used in undiagnosed HIV infection; periodic verification of HIV-negative status is required. It should be used along with safe sex practices and it must be taken every day without fail. It can cause kidney problems, lactic acidosis, and bone problems. Its safety in pregnancy is not known.
Patients should weigh at least 77 pounds and be at risk of infection with HIV.
Who is a candidate for PrEP?
Truvada can be used to treat HIV/AIDS, but it has also been recommended for people who are HIV-negative if they:
- Are men who engage in unprotected anal sex with other men
- Are in a sexual relationship with an HIV-positive individual
- Do not use condoms
- Are transgender individuals who engage in high-risk sexual practices
- Engage in transactional sex (for money, drugs, etc.)
- Inject drugs and share equipment or are in high-risk groups
- Use stimulants like methamphetamine that are associated with high-risk behaviors
- Have been diagnosed with more than one anogenital sexually transmitted infection in the past year
What about circumcision?
An article in The BMJ explained:
there is now compelling epidemiological evidence from over 40 studies which shows that male circumcision provides significant protection against HIV infection; circumcised males are two to eight times less likely to become infected with HIV. Furthermore, circumcision also protects against other sexually transmitted infections, such as syphilis and gonorrhea…
It is recommended by the World Health Organization and has been adopted in Africa as a means of reducing HIV infection, but it has been criticized as inappropriate in developed countries with good hygiene, and many people are adamantly against circumcision for various reasons, some better than others. Most of the objections are ideological and philosophical rather than based on any scientific evidence of harm.
Superstition and science denial
Science has made considerable progress in understanding, treating, and preventing HIV/AIDS. But it has had to fight superstition and science denial every step of the way. There are still those who claim that poverty, not HIV, is the cause of AIDS, that anti-retroviral drugs are poisons, and that HIV tests are flawed. All kinds of untested, ineffective remedies have been proposed; the infamous Dana Ullman even recommends homeopathy for AIDS. These people ignore the evidence or try to explain it away, sometimes with fatal results, as in the case of Christine Maggiore, who refused anti-retroviral treatment for herself and her 3-year-old daughter. They both died of AIDS. Herbal remedies have been used in place of effective drugs. Hundreds of thousands of South Africans died unnecessarily because science denial influenced public policy: the health minister, Dr. Manto Tshabalala-Msimang was an AIDS denialist who promoted dietary measures like lemons, garlic, and olive oil and denied effective drugs to patients in South Africa. She was known as Dr. Beetroot for one of her dietary AIDS cures.
Conclusion: Science saves lives; superstition doesn’t
Science works. Scientific discoveries have identified the cause of HIV/AIDS, have saved lives, and have turned a deadly diagnosis into a manageable chronic disease that doesn’t even shorten life. Alternative medicine has nothing to offer but false hope; people who rely on diet, herbs, or homeopathy die. We can hope for an effective vaccine, but meanwhile we have effective treatments and effective preventive measures such as Truvada. In the 21st century, no one should become infected with HIV or die a preventable death because of ignorance or misinformation.
This article was originally published in the Science-Based Medicine Blog