Are we still in the HIV prevention business?

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Barcelona, Spain: A considerable portion of a European Parliament session last week centered on one question: “Are we still in the HIV prevention business?”

In retrospect, the question was probably inevitable. Over the past week, and on Friday, the European Health Ministers followed through on the latest recommendation from the European Commission’s “Packaging and Dissemination Guidance” office, which called for all pharma companies (and presumably most if not all manufacturers) to include new strains of the preventative drug candidate, covidien-19. It’s an expensive drug that has been consistently in clinical trials since the early 1990s. If it works, it has the potential to save hundreds of thousands of lives per year. However, unlike existing HIV vaccines and past disease vaccines, which typically work against monovalent HIV, the immune system can never learn to attack an entire strain of the virus, such as those found in a group called active CD4 T cells, which forms the backbone of any sort of broadly-acting immune response. The covidien-19 approach aims to kick in before any dangerous structural changes have occurred, thereby more broadly blocking the virus before more destructive modifications have occurred.

Not surprisingly, scientists consider the covidien-19 the most promising HIV vaccine developed, but before now it was simply considered a cruel death sentence, a way to make certain people immunized as soon as possible, which would prevent further immune system development that could one day bind to the CD4 T cells that covidien-19 activates.

Before a recommendation like this could take effect, the political climate needed to be changed. A new law needs to be passed in each country that has signed on to the deal, and that’s actually still the case in some European countries — Portugal and the Czech Republic among them. Czech Republic, for instance, recently failed in its own attempt to require HIV vaccines. So it comes as no surprise that Poland’s Parliament rejected a similar proposal back in late 2014. However, according to Andrew S. Cherne, a PhD student at the London School of Hygiene and Tropical Medicine and the holder of the Lott Fellowships at the United Kingdom HIV/AIDS Trust, the situation is much better now in other European countries.

Currently, on the west coast of America, Proposition 64, which legalized recreational use of marijuana, is in the process of getting legal and it seems likely to expand the pool of potential covidien-19 recipients. Without too much of a hitch, Pharmacy Ufizal Beyo MD PhD MPH of Boston University notes that people who are at high risk for infection (such as intravenous drug users, AIDS patients, sex workers and gay men) may be the ones least able to find access to the drug. And though the Americans are closely watching the European experience for insight, experts say there are other reasons to keep the mindset of European governments in mind.

“It is really important not to write of all countries differently,” Cherne says. “It would be a disaster to play European (covidien-19) politics in the US and Sweden [which already requires HIV vaccine vaccinations] every two or three years. It would be a lot more convenient if things were just enough the same all around.” The approach has its skeptics, of course, but as a result of successful EU demonstrations of the difunctive effects of changing the political climate, there is now hope the global landscape could change before another continent loses its innocence.

The CD4 T cell

CD4 T cell can be thought of as a sort of hunter-gatherer’s super-refrigerator in the body. When unprotected, a Western AIDS patient infected with HIV will usually be immunized around seven months after infection, according to the World Health Organization. But in regions where HIV control is particularly weak, the incidence of AIDS among intravenous drug users is much higher, and they’re typically immunized far later, about six to nine months after infection. Because any HIV infection can trigger a massive recovery of CD4 T cells, it’s possible that maybe the vaccine doesn’t cause antiviral effects until a person has been exposed to the virus for seven months, which is why the T cell count may begin to rise even earlier than the first time someone is vaccinated.

Researchers have found that the antibodies produced by HIV vaccine recipients also react to parts of the virus they encounter, and it could explain why the immunity seems to still be forming with the earliest provocations. As researchers add new strains to the current program, the CD4 T cell count could begin to rise.

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