The human immunodeficiency virus (HIV) continues to spread around the world, mainly through sex. Despite advances in treatment, preventing infection is still the great challenge ahead. In the absence of an effective vaccine and after the repeated failures of vaginal microbicide gels, pre-exposure prophylaxis (PrEP), the taking of drugs before being exposed to the virus, is considered one of the most promising strategies for achieving this goal . A new study in monkeys showed that intermittent therapy before contacting HIV is effective.
The researchers, from the CDC (Centers for Disease Control and Prevention, USA), exposed the macaques to simian immunodeficiency virus (SHIV) modified to be as identical as possible to HIV. In different groups were given different doses of antiretroviral drugs and at different times to see what combination offered the best protection.Their findings, published in ‘Science Translational Medicine’, show that those animals that received a dose of the drug Truvada (tenofovir / emtricitabine) one, three or seven days before exposure to virus and a second dose after two hours were the best protected from infection. The risk of contracting the virus was reduced from 10 to 16 times.
As explained ELMUNDO.es J. Gerardo Garcia-Lerma, Department of HIV Prevention at the CDC, “pre-exposure prophylaxis is not a new concept and is being studied in several clinical trials in approximately 20,000 volunteers across the world. The feature of these trials is that all treatments evaluated daily. The novelty of our work was based on the assumption that you may not need daily therapy that can prevent infection and also with simplified intermittent treatments consisting of only two tablets, one before exposure to the virus and one after.
The work has shown that the hypothesis was true and that, besides the most effective combination mentioned above, take the treatment two hours before or two hours after virus exposure, which was rectally, also reduces transmission up to four times.
Preliminary results
“Although preliminary data are quite remarkable,” the Spanish investigator. However, for this strategy to make the leap to humans, “we still have to wait to know what is the efficacy of daily treatments on them, if there are any side effects or relaxation of preventive measures. Surely along this year we will have the first results and, from there, develop the strategy, “explains Garcia-Lerma.
Preventive therapy is a somewhat drastic measure, but for the expert from the CDC, “the severity of the AIDS epidemic, which affects 33.4 million people around the world requires new methods of prevention can complement existing strategies.
Still, he clarifies that “can be useful only in certain high risk groups like gay men, drug users injecting, discordant couples and women at risk.” And in any case “should be combined with other existing prevention strategies.
Tags: AIDS, HIV, preventive treatment
