Time to Prepare for “PrEP”

It all began with a 1994 study that showed antiretrovirals given to
HIV-positive pregnant women before and during childbirth – as well
as to the child upon delivery – reduced the risk of mother-to-child
HIV transmission by 50%. Next were the post-exposure prophylaxis
guidelines issued by the Center for Disease Control and Prevention
in 1998, recommending an antiretroviral regimen for healthcare
workers after unintended HIV exposure. Then, 2006 brought exciting
data gleaned from a study of monkeys who remained uninfected after
repeated exposure to a HIV-like virus as a result of taking the
antiretroviral drugs tenofovir and emtrictabine. These studies
raised the question: Can drugs prevent HIV? After recent
unimpressive results in vaccine and microbicide tests, scientists’
leading hope for stopping HIV infection before it starts seeks to
answer that question with pre-exposure prophylaxis, or PrEP.

By the middle of next year, close to 15,000 individuals will be
enrolled in PrEP trials. That’s more people than all HIV vaccine
and microbicide trials combined. In the PrEP approach, an oral
antiretroviral agent (specifically, Viread or Truvada) is taken
daily to prevent HIV infection. In theory, this method inhibits HIV
replication and permanent infection from the moment the virus
enters the body. If proven safe and effective, PrEP could
significantly reduce the risk of HIV infection for high-risk
individuals all over the world. It would be particularly
advantageous for individuals in serodiscordant relationships as
well as those unable to negotiate other proven protective measures
such as condom use. Perhaps most importantly, PrEP would represent
the first female-initiated intervention method.

Currently, three studies conducted by the CDC are underway to test
the safety and effectiveness of PrEP. In Thailand, injection drug
users are using once-daily Viread. In Botswana, young heterosexual
men and women are taking once daily Truvada, and in the US,
once-daily Viread is being tested among men who have sex with
men.

PrEP is quickly becoming a reality. Over the course of 7 years, the
CDC will spend an estimated $53 million researching PrEP. Most
importantly, the CDC has recently urged public health leaders to
begin planning for PrEP implementation. The time has come to
discuss the optimal use and delivery of PrEP if found effective.
PrEP raises particularly challenging questions that need attention
now. How will we ensure that individuals use PrEP in concert with
other proven preventative strategies? Some people may refuse to use
condoms if they learn that their partner is taking PrEP and,
theoretically, protected from HIV transmission. No single strategy
will likely be 100% effective against HIV infection, and reducing
transmission will require integration of all biomedical and
behavioral methods. How will healthcare providers ensure that PrEP
is used before exposure, and not after infection, to prevent
drug-resistant HIV? Who exactly would be prescribed PrEP? Would
people be required to prove that they are at "high risk," and if
so, will that lead to their being stigmatized? What will happen if
an individual disregards instructions for daily use and takes the
pill before a night on the town? Will this ineffective so-called
“disco dosing” become rampant? Already, rumors are emerging of new
drug cocktails of Truvada, Viread, Viagra and Ecstasy that are
being sold in gay dance clubs.

Clearly, this new strategy will not be a panacea for the difficult
issues involved in the HIV pandemic, including stigma, the
sexuality of young people, drug use, homophobia and the sex
industry. PrEP may one day be an important response to AIDS, but
that response will never be equitable nor ultimately successful
unless we begin planning for it now.

I’m Charlotte Steelman. Thanks for listening.