Two consecutive sessions at the sixth International AIDS Society conference (IAS 2011) in Rome
yesterday were devoted, now we have convincing scientific data on the benefits
of treatment as prevention and PrEP, to putting these new prevention methods
“We have moved from ‘What if?’ to ‘What now?’” was the
comment of Mitchell Warren, Executive Director of the AIDS Vaccine Advocacy Coalition (AVAC), on what else we need to know, what barriers need to be
addressed , and what resources might be required, to maximise the promise of antiretroviral-based prevention.
Anthony Fauci, Director of the US National Institute of Allergies
and Infectious Diseases (NIAID), said: “We now have a solid scientific
foundation to say that even in the absence of a vaccine we have the capacity to
end the epidemic. I can’t go to the US President and say: 'We can cure HIV.’ But
I can say ‘Ending the epidemic is scientifically doable’.”
"I can say ‘Ending the epidemic is scientifically doable’.” Anthony Fauci
Earlier, however, Nancy Padian from the Office of the US
Global AIDS Coordinator had outlined formidable challenges still to
be answered if antiretroviral treatment could bring about this goal.
She said that questions still needing answers
include whether antiretroviral drugs (ARVs) really are a durable and reliable
means of viral load suppression over a period of years and whether increasing
the proportion of people on treatment would lead to increased levels of
resistance. The biggest practical question, however, was whether treatment as
prevention would work in situations where a high proportion of transmissions
came from people with acute, recent HIV infections.
The biggest barriers to treatment as prevention, however, are stigma and lack of resources. Implementing ARV-based prevention would not
only be expensive in terms of drugs; it would require added human resources and
increased training and task-shifting for prevention counsellors so they can
deal with biomedical data. There would also be added costs in terms of tests
The other big barrier will be the stigma of being tested, she
said, particularly for at-risk populations in societies where injecting drug
use, male-male sex, or sex work were criminalised and stigmatised. Treatment as
prevention would require people not simply to test and then go to more supportive
community organisations for prevention advice; it required a much closer
relationship with medical personnel who might be prejudiced or feared to be so.
Mitchell Warren issued a call to action to implement the new
strategies, but his presentation was tempered by realism. “We have evidence, we have data, and we now need
to make decisions,” he said.
“We have evidence, we have data, and we now need to make decisions,” Mitchell Warren
said, we need "smart combinations" of prevention interventions tailored to
different people and populations. “It can be seen as frustrating to have
all these tools (he counted 13 different ones for which there is now evidence)
and not know what to choose or how to pay for them,” he said, “but it’s a
better kind of frustration than in 2004” (at the time of the closing of the
first PrEP study in Cambodia).
Given that, even now, only 8 to 9% of people who need
them have ready access to condoms or clean needles, only 11% of gay men have
access to behaviour-change programmes, and only a third of HIV-positive mothers
have access to ARVs to prevent transmission to their baby, making ARVs more
widely available as prevention or PrEP would be a big challenge.
Using ARVs for prevention would continue to be a behavioural
issue, he added, in terms of people coming forward for testing and, crucially,
One important consideration was to match the prevention intervention
to the person. PrEP, for instance, had been criticised as a ‘niche intervention’,
but niche interventions were important for specific groups of people and could
be extremely effective; an example from another context was injectable
Lastly, of course, money and resource allocation would be a
huge issue. “Scientific data do not change the world
– programmes and policies
backed by civil society, donors, implementers and governments do,” he said.
In this context, Tim Farley of the World Health Organization,
presenting a comprehensive review of the licensing processes needed for
ARV-based prevention methods in the USA, Europe and Africa, remarked on the
extreme range of prices paid for tenofovir and Truvada in different contexts, from $35.82 as the US list price
(almost always discounted) for one Truvada
tablet, to $0.87 as the ‘no profit’ price paid to the developers
Gilead in low-income countries and the even lower $0.28 for a generic
equivalent. He noted, however, that Gilead was already licensing generic
companies to produce tenofovir and Truvada
at lower prices.
Helen Rees, University of Witwatersrand in South
Africa, said that the new data from the treatment-as-prevention and PrEP studies
had come along just as she was involved in writing the country’s new National
Plan for HIV. She said that the new prevention choices offered could feel bewildering.
“Do we put more people on treatment, circumcise all men or buy millions of
condoms?” she asked. As an initial step, the country had extended its CD4
criteria to 350 cells/mm3 in line with WHO guidelines and had
decided that, with still only 45% of those who need it on treatment, that treatment
access remained South Africa’s biggest priority.
She added, however, that the data from serodiscordant-couple
studies did not necessarily provide the kind of data needed on the likely
effectiveness of treatment as prevention, or of PrEP. “South Africa is a
country of female-dominated households and a low level of marriage,” she said, “and
serodiscordant couples are hard to identify: men still won’t come forward.” It had been decided that HIV-negative women wishing to conceive who were or might be
having sex with HIV-positive men were a logical first population who might need
PrEP, but setting up PrEP as a service was a much bigger step than expanding
existing HIV treatment, as it involved a new type of service that didn’t yet exist.
Myron Cohen, principal investigator of the HPTN 052 study,
said that if the world did not pay for ARVs now it would do so later, in terms of
an indefinitely increasing number of people needing HIV treatment. He said that
his study’s findings did not imply a huge expansion of treatment to groups not
previously entitled to it; for the study’s purposes, it had needed to
offer ARVs to people with relatively high CD4 counts but the reduction in
infectiousness should apply to people with CD4 counts below 350 cells/mm3
too, and should serve as a further incentive to get ARVs to the two-thirds of people
with CD4 counts below this figure who were not yet on treatment.
Above all, moving from the data provided by scientific
studies to the business of trying to make HIV prevention work in the real world
was an exercise in dealing in uncertainty. Microbicide researcher Ian McGowan
of the University of Pittsburgh commented that: “In an ideal world, we’d treat
all the HIV-positive people and the negative ones would use condoms. But people
may not go on treatment, may fail treatment, and may fail to use condoms. The
world has never been black and white, and the debate about moving from
treatment, to treatment-as-prevention, to PrEP is the kind of debate we have
been having on access to medications for HIV ever since we’ve had them.”