The over-hyped story of a new “HIV Vaccine” cause a lot of people working in public health to worry.

Every time these stories come out, there are laypeople who think: well, there will be a vaccine so I don’t have to change my behavior”, and voila, case numbers spike.

That is why the Department of Health here in the Philippines is advising people that condoms work better than this vaccine, and that they will continue to advise folks to be abstinent, monogamous, or use condoms.

Here in the Philippines, the HIV rate is low, probably because the government and culture stresses abstinence and fidelity for ordinary folks, while gays and sex workers are not stigmatized as much as in the US. As for condoms, you can easily find them in grocery stores right next to the gum, batteries,  and toothbrushes.

But what is exciting about the HIV vaccine is not that it works, but that they’re not sure why it worked, and that finding might be the key to an actual vaccine.

Let me tell you about vaccines.

In the past, they either made the germ weak to give you a very mild case of the disease so that you would be immune (example, measles, small pox), or else they would kill the germ and give you part of the dead germ or toxin(usually the coating of the bacteria or virus) and your body would make antibodies (example, tetanus, diphtheria, hepatitis).

But they ran into a problem: sometimes they couldn’t get a good immune response with the dead germ, and the weak “attenuated” germ vaccine didn’t work either.

So what to do.

The answer: Combine part of the germ with something that gives a strong immune response.

That is what they did with the pneumonia germ.

Variations of the killed vaccine against pneumococcus have been around since the  1940’s but interest in the vaccine waned until drug resistance to antibiotics started being a problem.

But the adult Pneumococcal vaccine didn’t work in very young kids, where pneumococcus infected not only lungs but ears and caused meningitis.

So they pasted the coat of the pneumonia germ to weakened diphtheria toxin.(aka “conjugate vaccines”)

The pneumococcal conjugate vaccine (PCV7) includes purified capsular polysaccharide of seven types of the bacteria “conjugated” (or joined) to a harmless variety of diphtheria toxin.

This idea is now being expanded into making a lot of the newer vaccines.

The HIV vaccine study, for example, did not use one vaccine, but a series of two vaccines.

One was combined with a cold virus, the other with canarypox virus.

Yes, the simple cold virus is being examined at Johns Hopkins to see if they can develop a cheaper HPV vaccine. Other scientists are working on a Malaria vaccine, using a modified monkey version of adenovirus.

The other shot used in the HIV vaccine trial use canarypox, which doesn’t make humans sick, to try to induce T cell immunity.(a form of white blood cells).

The strange part of all of this is that both of these vaccines did not work in earlier trials, but when they were both given, those that received the vaccine had fewer HIV infections. Here are the numbers involved, to give you an idea of what we are talking about:

74 of 8,198 placebo recipients became infected with HIV compared with 51 of 8,197 participants who received the vaccine regimen

And these patients were not high risk sex workers or addicts, just ordinary folks, all of whom were given condom/prevention education along with either the vaccine or placebo.

But more puzzling, those who did get HIV didn’t get a lower HIV viral count, which should be lower if antibodies were destroying the HIV virus.

So what is going on? Could the findings be a statistical fluke? Or did the vaccine work but the scientists didn’t check for the correct antibody/cell response?   Scientists will now do a lot of research to figure out what worked and how, and one hopes that these studies will help them to make a vaccine that works in the near future.

For those who want more information, the New York Times article is the most comprehensive review.

In the meanwhile, be pure, stay faithful, and use condoms if you aren’t.

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Nancy Reyes is a retired physician living in the rural Philippines. Her website is Finest Kind Clinic and Fishmarket, and she writes about medical problems at Hey Doc Xanga Blog.

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