In the past 20 years, scientists have tried and failed at more than 100 attempts to discover a vaccine against HIV. The problem is that viruses mutate, rendering vaccines hard to produce. But if one of them finally works in a clinical setting, will it actually benefit people?
“Right now, there is, for instance, a hepatitis B vaccine,” says Peter Newman of the University Of Toronto’s Faculty Of Social Work. He specializes in the social science aspects of HIV/AIDS and has conducted research in the US, Canada, India and Thailand. “But how many men who have sex with men get that vaccine? Well under 50 percent. Just because we have a vaccine doesn’t mean that it will get to the people who need it.”
Research in the US has shown that immunization levels against many common infections are as much as 50 percent lower among African-American and Latino adults and children. But even when a vaccine offers protection against something as dangerous as HIV, people still move into fear mode.
Whereas sometimes a lack of information or awareness can be the reason, some attitudes are more extreme. According to a 2004 report from the Sixth Canadian Immunization Conference, the antivaccination movement, which has started to play a role in health politics in the UK and US, is growing in Canada. Opponents of vaccinations claim that vaccinations aren’t effective and can do damage.
Newman says that participants in a major study he was involved in in Los Angeles were worried about the possibility that an AIDS vaccine would make them test positive for HIV, which made them feel uncomfortable, even if they did not contract the virus.
“A false-induced positive is possible. People have a fear of being infected. That is not going to happen,” Newman says. “But scientists are working on more sensitive assays that can distinguish between HIV seropositivity from a vaccine or from infection.”
Through his research in the US and in Toronto, Newman has discovered that acceptability of a vaccine is associated with how vulnerable particular individuals and communities are. Fear of testing positive for medical insurance and immigration reasons are big concerns for underemployed and illegal workers in the US who live without access to healthcare. Preliminary data Newman has collected among First Nations gay men in Toronto indicate that what he calls “social marketing” – educating different groups in ways that would address concerns specific to them – may be the most effective way of working with that community’s possible mistrust of government and concerns about Western medicine.
Newman stresses that there is the possibility that a vaccine would be only partially effective at first. For instance, how do you educate somebody about what 50 percent effectiveness means? Also, how do you drive home the idea that nothing is a cure-all, that individual responsibility – avoiding putting yourself at risk for infection – is always the major issue? That could be an even bigger job than finding than developing the vaccine itself.
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Roberta Halpenny is a researcher and coordinator for a vaccine test being conducted internationally, with the Maple Leaf Medical Clinic as its Toronto hub. Participants – men who have unprotected anal sex, men who have multiple sexual partners in a six-month period, women who have had sex with HIV-positive men, use injection drugs or crack or who have sex for money – are paid for their involvement in the study. It’s being done in partnership with Merck pharmaceuticals, the HIV Vaccine Treatment Network and the National Institute Of Allergy And Infectious Diseases.
Half of the participants get the trial vaccine while the other half get a placebo. Though participants are informed about the risks and are encouraged to have safe sex and use safe needle-sharing practices, the study does depend on some participants coming into contact with HIV.
“The goal of the vaccine is twofold: one is to teach the immune system to recognize HIV and to fight it right away,” says Halpenny. “The second goal is, if HIV is not fought right away and does multiply within the immune system and the body hasn’t killed it right from the beginning, we hope it will teach the immune system to react as if it were that of a long-term nonprogresser.” Long-term nonprogressers are HIV-positive people whose immune systems remain relatively healthy and whose viral loads remain low for reasons not wholly understood.
Halpenny says that a previous trial a few years ago for a vaccine called VaxGen was unsuccessful, but researchers were still able to learn from it.
“I don’t think this [trial] is going to be the be all, end all. But I do think they believe it is going to teach them a lot and the volunteers will be so appreciated. We wouldn’t be where we are today with HIV and the kinds of drugs we have, and the classes of drugs we have, if we didn’t have people who volunteered. So anyone who is a study volunteer is very appreciated.”
? With files from John JJ Martin
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