One antiretroviral pill taken daily, according to the Centers for Disease Control and Prevention (CDC), halves the risk of HIV infection among injection drug users.
Getting the pills to high-risk groups like intravenous drug users and ensuring that they take the pills on a daily basis might be easier said than done, though. However, the individuals who took the antiretroviral pills the most consistently had even greater levels of protection from HIV infection than the 49 percent figure reported among those who were less consistent taking the pill daily.
The CDC’s PrEP strategy of attacking HIV among injection drug users by providing them with antiretroviral pills like tenofovir before they ever get infected with HIV could result in lower rates of HIV among this high-risk group. “PrEP” is an acronym which stands for pre-exposure prophylaxis.
Injecting drug users are usually endangered in at least two ways: through the sharing of needles, which can transmit the virus, and also through indulging in risky sexual behavior. Drug users can spread the virus to non-drug users via sex.
These latest findings of the CDC are the first indication that PrEP gives significant protection to individuals exposed to HIV through injection drug use. Taking the daily antiretroviral pill doesn’t guarantee immunity from becoming infected with HIV; but, one’s chances of contracting HIV are substantially lowered.
This is a major step forward for HIV prevention, according to Dr. Jonathan Mermin, director of CDC’s Division of HIV/AIDS Prevention. Injection drug use, Mermin says, is responsible for a significant portion of the HIV epidemic around the world. Researchers believe that PrEP can reduce the impact of HIV infection in this population.
The Bangkok Tenofovir Study is where the findings of the CDC come from. It involved a trial of the antiretroviral pill and more than 2,400 men and women at drug treatment clinics in Bangkok where the participants in the study.
Injection drug use, according to the CDC, is responsible for eight percent of new HIV infections in the U.S. and about 10 percent of new HIV infections worldwide. That might not seem like very many cases, but factor in the injection drug use in Eastern Europe and Central Asia, and the figure then rises to as much as 80 percent of new HIV infections.
Further good news is that daily PrEP with tenofovir has also been shown to lower the risk of sexual transmission of HIV among heterosexuals and men who have sex with men.
Among the 1,204 participants taking a daily pill of TDF, according to the researchers, there were 17 HIV infections, compared with 33 infections among the 1,207 participants taking a daily placebo pill.
In other words, a daily dose of antiretroviral pills lowered the risk of HIV infection by 49 percent.
Among the participants of the study, researchers also noted that the ones who followed the daily antiretroviral regimen the closest, taking the pill on at least 71 percent of the days and never missing more than two consecutive days, reduced their HIV risk by 74 percent.
Following PrEP is crucial, Mermin points out. Those who were the most consistent in taking the pills daily lowered their risk and benefited the most. According to Mermin, when PrEP is utilized consistently and in combination with other tested prevention techniques, the approach can offer significant additional protection for people who are high risk for HIV, especially those who use injection drugs.
“This is a significant step forward for HIV prevention. We now know that PrEP can work for all populations at increased risk for HIV,” Mermin stated.
While there’s no cure for the human immunodeficiency virus (HIV) that causes AIDS, cocktails of drugs can keep it under control and keep patients healthy for years, even decades.
The same drugs can be used to prevent infection.Newborn babies are given drugs such as nevirapine to prevent their mothers from infecting them. Also, several studies have shown the spouses and sexual partners of infected adults can take another drug, called tenofovir, and lower their risk by as much as 62 percent.
According to Dr. Salim Karim, Director of the Centre for the AIDS Programme of Research in South Africa (CAPRISA), in a Lancet commentary, it’s one more tool for fighting the virus, which infects 2.7 million people every year, including about 50,000 in the United States.
“The introduction of PrEP for HIV prevention in injecting drug users should be considered as an additional component to accompany other proven prevention strategies like needle exchange programs, methadone programs, promotion of safer sex and injecting practices, condoms, and HIV counseling and testing.”
The study adds ammunition to arguments that HIV drugs should be made widely available to fight the epidemic that has killed more than 25 million people, especially when just one pill taken daily can halve the HIV risk among injection drug users.
The medical journal Lancet discusses the findings in detail.
Written by: Douglas Cobb