An HIV Vaccine: Efforts and Controversy

Thirty-two million men, women and children have died worldwide due to AIDS and HIV infection. For 20 years, scientists, doctors, and humanity have been eager to find a vaccine to protect lives from the destruction of HIV/AIDS. Although we wished it would come sooner, scientists may be on a lead to discovering an effective, marketable vaccine for HIV.

Due to the popular commercial sex industry and injection-drug users, the HIV-1 prevalence dramatically increased since the 1980’s. The Thai government quickly responded with an effective HIV-prevention campaign that decreases HIV-1 infections per year from 143,000 in 1990 to 14,000 in 2007. However, they were still on a search for a vaccine that would promise protection and control of the HIV pandemic.

From September 2003 to December 2005, 6,176 people received the vaccine and 6,366 received a placebo. They were healthy men and women ranging from the age of 18 to 30 years old. The subjects were primarily at heterosexual risk for HIV infection. The vaccine efficacy was 31.2% for the intention-to-treat group. The figure below shows the enrollment and outcome population.

The efficacy percentage of 31.2% is obviously not anything too earth shattering—56 were infected with HIV in the vaccine groups versus 76 in the placebo. However, it is a good start as a vaccine to use and develop to perfection.

However, there are a few points of controversy.

Firstly, this vaccine is only effective on the HIV-1 subtype B, which is the predominant subtype in American and European countries. This neglects the HIV-1 subtypes C, A, and G, which are predominant in African countries. This is a major concern of injustice. It is obvious that companies want to invest in a virus and disease that affects the wealthy populations who can purchase the vaccine. However, the African countries need the vaccine as well, if not possibly more.  Sixty-four percent of all people living with HIV are in Sub-Saharan Africa.

Secondly, the vaccine used in this clinical trial depends on the ALVAC-HIV priming and AIDSVAX B/E boosting drugs for prevention of HIV-1. However, AIDSVAX was previously shown ineffective. However, the research data from various sources seems to be contradictory. In one article though the dilemma is solved: the AIDSVAX was in effective at producing broadly neutralizing antibodies but with a priming and boosting dose the AIDSVAX seems to be effective to a low degree of 31.2%. A successful HIV vaccine will most likely activate broadly neutralizing antibodies and cytotoxic T lymphocytes. Immunological memory is a key concept in vaccine development as well as neutralizing antibodies and cytotoxic T lymphocytes therefore both being necessary and needed for an effective HIV vaccine.

Thirdly, although there was a study oversight by the ethics committees of the Ministry of Public Health, the Royal Thai Army, Mahidol University, and the Human Subjects Research Review Board, it still seems that an unethical decision may have been made during this trial. If 20 people were prevented from contracting HIV due to the vaccine, then in the placebo group approximately 20 people could also have been prevented from acquiring HIV.  I understand that there was a credible source of oversight for this experiment, but something still seems inherently immoral to me. I think it is very important that young scientists, veteran scientists, and non-scientists continually take responsibility for our current technology and medical practices to ensure that wrong steps are not being made.

Fourth of all, there is still controversy over the debate if HIV even exists at all, is directed towards Africans and African-Americans, or if HIV is linked to AIDS. I have no researched the history of HIV/AIDS well enough to conclude if these conspiracies or false, however I am not able to rule out the argument due to my lack of knowledge. However, one of my greatest fears is that a differing, hint of truth will be ignored and without pursuit do to the selfish concern for maintaining a multimillion dollar HIV/AIDS industry. If one of these controversies were proven true, it would possibly damage if not ruin the HIV/AIDS industry of not-for-profits, research companies, pharmaceutical companies, etc. On the other hand, the fact that some of these controversies are being supported delays progress for HIV/AIDS treatment and prevention. This situation can be imagined if someone believes that the HIV medications actually cause AIDS and death and therefore the search for vaccines and treatment is not pursued or supported.


~ by tiamalcom on November 24, 2009.

2 Responses to “An HIV Vaccine: Efforts and Controversy”

  1. Tia,

    Interestingly, I just finished helping my brother edit his term paper on …dun dun dun… antigenic drift and random mutation in viruses (ironically written for an honors English class). He focused on HIV and the difficulty in creating a vaccine. An interesting stat we gleaned from Freeman’s book Biological Science was that reverse transcriptase inserts the wrong nucleotide base about once every 8000 base pairs, meaning that a new HIV mutant is generated each time HIV replicates. Considering that a person with HIV harbors about 10 billion viruses within their body (another stat), they contain, on average 10 billion genetically different strains. Thus, it is unlikely that any vaccine creation (even against a specific subtype) would remain effective in a population for any appreciable amount of time, given the high mutational frequency leading to antigenic drift in these viral particles.

    Similarly, this mutation rate is the reason that HIV drugs often fail. There are three main types of HIV drugs: nucleoside analogues, non-nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors. Nucleoside analogues are chemically identical to the nucleosides present in our body except that they lack the 3′-hydroxyl group that is required for DNA-chain elongation. Since reverse transcriptase uses the host’s DNA to reverse transcribe the viral RNA-based genome into DNA for insertion into the host’s chromosomes, this inhibits the ability of the virus to replicate. NNRTIs work simply by inhibiting the reverse transcriptase enzyme. Protease inhibitors inhibit the viral proteases that are required to cleave long peptides into functional viral proteins.

    Usually, a “cocktail” of the aforementioned drugs are prescribed, and dosages and composition of the cocktail can be changed if the virus begins to show resistance. This resistance is conferred by HIV’s high mutational frequency.

    As such, creating a prophylactic vaccine or treating HIV with drugs seems rather like a race between researchers and the virus. Can we make new drugs as fast as HIV can mutate? I think the answer is likely not. How do we treat HIV then? Novel therapies are being developed, but I don’t want to steal Kevin’s thunder, so I won’t discuss them here.

  2. Oh, and one more thing: Do you think it’s ethical to even be testing this vaccine in a rigorous scientific way (aka, using placebos???)…

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