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AIDS Vaccine Trials: How Risky?

Debate continues over running test with Downtown Eastside women.

By Danielle Egan 1 Feb 2006 | TheTyee.ca

Danielle Egan is contributing editor on The Tyee.

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A Tyee story last month about proposed experimental HIV prevention vaccine trials in Vancouver's Downtown Eastside drew criticism from a key backer of the trials, Dr. Mark Tyndall, program director of epidemiology for BC Centre for Excellence in HIV/AIDS.

His comments reveal a strong divide between certain Downtown Eastside advocates who believe vulnerable women are put at risk by participating in the trials and medical researchers pushing the project.

And a follow-up interview with Tyndall, as well as additional reporting by the Tyee on the issue, show the disagreements are not likely to go away soon.

The December 8 Tyee article said Tyndall and his team were approaching groups to recruit subjects on the Downtown Eastside. Advocates from those groups, the Tyee reported, were worried that women living in poverty, struggling with drug addiction and involved in the sex trade might be put at risk by participating in the drug trials.

Among the risks cited: the vaccines might compromise their immune systems and the experiment might also encourage greater sexual risk taking among trial participants.

The Tyee report noted findings by some experts in human biology and social science supporting those concerns. Tyndall was contacted and asked to be interviewed for that article, but was not available to be interviewed before it was written.

Director disputes Tyee report

After the article appeared, Tyndall told the Vancouver Sun the risks had been "erroneously" reported and that he believes "there are certain people who seem to be spreading a lot of misinformation around." As a result, he said, the planned clinical trial is now in jeopardy.

Though the Tyee story said subjects were already being recruited, actually, Tyndall said, he and his team were just beginning to take the pulse of the local community.

He also disagreed with women's advocates who said their groups were being courted by Tyndall's project with offers to provide funds to the groups and their needy clients.

The Sun quoted Doreen Littlejohn of the Positive Outlook Program of the Vancouver Native Health Society who voiced support for the trial and claimed Tyndall had not already attempted to "brief sex trade workers."

But the same story confirmed that various local women's group advocates are opposed to clinical trials involving their centres and clients.

"Your article contained a number of inaccuracies that I have been trying to deal with," Tyndall said when approached by this reporter for a follow-up article.

What about the fears of virologists, noted in the Tyee article, that DNA-based vaccines will compromise participants' immune systems or even cause genetic mutations?

"Your article wasn't very accurate," says Tyndall who has worked as an infectious disease doctor on HIV prevention since the late 80s, first in Kenya and now in Vancouver. "This is a very controversial area and I'm not a virologist," admitted Tyndall.

"But I'm familiar enough with vaccine literature. A whole spectrum of specialists in this field have found the vaccines to be safe compounds. The majority of the scientific world thinks these vaccines aren't risky for the immune system. Sure, there's a ton that's not known about these vaccines but I'm fairly confident based on the information I have on-hand. It needs to be recognized that a lot of virologists and immunologists have researched this to the point that a clinical trial is justified."

'Danger of misconduct'

And yet, other virologists say the opposite.

"Based on many presented facts, a safe and effective preventive AIDS vaccine is not possible," says Veljko Veljkovic, a virologist at the Belgrade-based Center for Multidisciplinary Research and Engineering at the Institute of Nuclear Sciences.

"We have been warning there should be a moratorium on these vaccines for over five years. Even worse, some described phenomenon indicate the possibility that AIDS vaccines based on the HIV-1 envelope protein gp120 [used in DNA-based HIV prevention vaccines] may be worse then useless [and] could accelerate disease progression in vaccinated individuals by inducing 'deceptive imprinting' and perturbing the immune regulatory network.

"Our results strongly indicate the possibility that these vaccines would only act as a decoy for the immune system, increasing the likelihood of infection, as well as disarming the immune system's antiviral response and thus accelerate disease progression."

Veljovic says the work of award-winning virologist Douglas Richman (formerly of NIH, now at University of California at San Diego) and other researchers "strongly pointed out a possible harmful effect of gp120-based vaccines" and showed that an "AIDS vaccine which induces such immune response after breakthrough infection could disarm their immune system" and cause "fast disease progression" in clinical trial participants, which "strongly confirmed possible" the dangers of these vaccines.

Documented fears about these vaccines date back to at least 1992, when prominent Cincinnati Children's Hospital-based vaccinologist Albert Sabin said it would be "disastrous" to continue human trials of DNA-based vaccines.

Veljkovic has been studying HIV immune system mechanisms for over twelve years, working with other concerned researchers in the UK, California, New Orleans and Kentucky. They have all published extensively on the harms of these vaccines in medical journals including The Lancet, Vaccine, various immunology journals, AIDS-specific journals and mainstream publications like Nature.

"In contrast, those that perform clinical trials of AIDS vaccines never reported this data," says Veljkovic, citing the only Phase III trials completed so far by US-based VaxGen. "Although it has been reported that 191 vaccinated volunteers and 98 individuals from the control group were infected with HIV during this clinical trial, VaxGen failed to provide data about their current disease status.

This data was also not included in the recent report of the National Institute of Allergy and Infectious Diseases HIV Vaccine Trials Network evaluating long-term safety data from 3,189 HIV-1 uninfected volunteers who were enrolled into 51 NIAID-sponsored clinical trials of AIDS vaccines. Unless this information is reported, the companies and institutions that organized these clinical trials are in danger of committing scientific and ethical misconduct."

Fully informed subjects?

Advocates say potential vaccine clinical trial participants should be informed about the potential immune system risks in order to truly make informed consent.

Will this issue be included in the informed consent process for the proposed Vancouver trials? "I don't think that's mentioned in the consent form. I'll have to look into it a bit more," said Tyndall.

What about the concern that subjects recruited for the study might be lulled into a false sense of security and, believing themselves vaccinated and immune from the HIV virus, engage in more risky sexual behaviour, upping their chance of developing AIDS?

Tyndall, who called this "erroneous" information in the Sun article, now acknowledges that "this is a legitimate concern, for sure."

Indeed, various clinical studies have found increased risk-taking, including a University of California San Francisco study of HIV prevention vaccine participants which found "significant increase" in unprotected anal intercourse from 9 percent at trial beginning to 20 percent after one year.

One Canadian study of risk-taking among AIDSVAX volunteers in Toronto, Montreal and Vancouver - 19 of whom became HIV-positive during the trial - acknowledged that previous Phase I and II trials found increased risk-taking.

The Canadian group's data concluded that risk rose from 21 percent to 27 percent among men who have sex with HIV-positive or status unknown partners and cumulative unprotected sex follow-up rates among all men in the trial increased as much as 40 percent after three years. However, the study concluded that there was no increased risk among their study participants.

Meanwhile, a University of Kentucky survey found that almost one-quarter of the HIV negative people polled "indicated a likelihood that their HIV risk behavior would increase after vaccination," that the increase was linked to the desire for a vaccine and that investigators must "identify strategies that minimize escalation of HIV-negative risk behavior after being vaccinated against AIDS."

What were women offered?

What about the question of how far along the project had gotten in recruiting female subjects in Vancouver? Has Tyndall made contact with independent sex workers and offered financial incentives to women's groups?

Cynthia Low of DEWC and Kate Gibson of WISH went on record with the Tyee that they had indeed attended meetings with Tyndall and representatives from Merck-Frosst, the pharmaceutical company developing the DNA-based vaccine. Gibson said that independent "street workers" also attended her meeting.

"There were two women at the meeting with WISH," Tyndall acknowledges in his Tyee interview. Were they independent sex workers? "They were peers who work in the community and we were merely seeing how they felt about the topic. That's much different than a [clinical trial] recruitment process which happens once the trial has been approved and all the safeguards are in place. I simply approached people in good faith to get a feel for how the community felt about a vaccine trial. Low [of DEWC] made it sound like we were offering them compensation."

So, no financial incentives were offered at these meetings?

"These groups voiced concern that this community needs assistance with housing and basic resources and that an HIV prevention vaccine wasn't a priority for them," said Tyndall.

"I said I was committed to the same sort of process and said we'd try to develop a package. We didn't really discuss financial incentives but we certainly expressed openness to helping them get resources like housing. Renumeration is a sensitive issue. We can't be seen as coercive with incentives and with any clinical trial, participants are paid a small sum, between $10 and $50; that's standard with any drug trial."

'Potentially desperate'

Advocates have pointed out that the smallest sum of money might seem tempting to this demographic of mostly Downtown Eastside sex workers and injection drug users, the targets for this proposed vaccine trial. The offer of a place to call home might seem particularly tempting.

"Yes, it's a touchy issue," says Tyndall. "They are potentially quite a bit more desperate. But we are dealing with a community with a 30 percent HIV rate who are at a lot of risk already. I wouldn't want to increase that risk."

Increasing risk is exactly what concerns some women's advocates in the Downtown Eastside who worry that, while the dream of an effective HIV vaccine is compelling, a trial involving women living in poverty could put healthy people in harm's way.

"We have to make sure there are as many safeguards as possible," said Tyndall. "But, my role is to find a site to get this study moving forward. This trial should be seen as a positive opportunity for HIV prevention. I spend all my time doing prevention and we need to be a part of that solution. Should we let another 40,000 people become HIV-positive without doing anything?"

Veljkovic is one researcher who believes we should be doing something other than developing and testing genetically modified HIV vaccines. "Based on the facts, a safe and effective preventive is not possible. Not one of our arguments have been denied among virologists," he says. "From a scientific point of view this story is finished."

Danielle Egan writes for a number of publications and is a regular contributor to The Tyee.  [Tyee]

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