17 March, 2010
13 March, 2010
I think most would agree that there are a lot of ignorant people in the world. Luckily, most of these individuals aren't a threat to the general public, just to themselves. But unfortunately, some are. Among the most dangerous are those who crusade on behalf of the anti-vaccine groups. They are quite literally encouraging the spread of disease (and sometimes death) by discouraging the use of vaccines.
The poster child for this movement is Jenny McCarthy (you know, the girl who gets paid to take her clothes off) who, despite a complete lack of scientific and medical training, reckons she is well-placed to comment on and dissuade the use of the MMR vaccine. Together with her supporters, including her husband Jim Carrey (you know, the guy who gets paid to make funny faces), she insists that this medically-validated vaccine causes autism.
In fact, the original research that apparently 'proved' this has recently been retracted by the Lancet, and the author who was largely responsible for the unethical behaviour has been widely discredited. The fact is, the MMR vaccine saves lives, and so by influencing parents to forego this important step in a child's health results in deaths (and many more illnesses).
McCarthy and co are actively causing death and disease. A website called www.jennymccarthybodycount.com is keeping tabs on this. At the time of writing the numbers were:
Number of preventable illnesses: 54,907
Number of preventable deaths: 501
Number of autism diagnoses scientifically linked to vaccination: 0
Anyway, this post wasn't meant to be about McCarthy or autism. Instead, I want to discuss a recent publication in Nature by Herbert W. Virgin and Bruce D. Walker, which discusses efforts to develop a HIV vaccine.
Here's the abstract:
"Developing a human immunodeficiency virus (HIV) vaccine is critical to end the global acquired immunodeficiency syndrome (AIDS) epidemic, but many question whether this goal is achievable. Natural immunity is not protective, and despite immunogenicity of HIV vaccine candidates, human trials have exclusively yielded disappointing results. Nevertheless, there is an indication that success may be possible, but this will be dependent on understanding the antiviral immune response in unprecedented depth to identify and engineer the types of immunity required. Here we outline fundamental immunological questions that need to be answered to develop a protective HIV vaccine, and the immediate need to harness a much broader scientific community to achieve this goal."
The authors first remind the readers of the scale of the problem; in some regions, HIV infection rates in young women can increase from 1% at the age of 15 to over 50% by their early 20s - an incredible difference within a few years.
Here is the problem.... Vaccines work by stimulating the natural immune response.
This is usually an effective method as the body is somewhat adept at clearing vaccines. The main setback in developing a HIV vaccine is that the natural immune response isn't very effective against HIV and, accordingly, attempts to promote a vaccine-induced response to HIV have been equally as ineffective. Despite this alarming obstacle, the authors remain confident that a vaccine can and will be developed, although they admit that whether this vaccine will prevent infection, or instead prevent disease progression, is hard to predict. They mostly base this on studies in monkeys infected with simian immunodeficiency virus (SIV), which is very similar to HIV and indeed, is thought to be a candidate for its origins.
However, the fact that not all HIV infection lead to AIDS is encouraging, because this means that natural immunity capable of preventing disease progression does exist. Some individuals can harbour HIV for 30 years, and live relatively normal lives without developing AIDS. It is the, as yet unidentified, immune factors behind this remarkable resistance that must be harnessed in order to develop a robust HIV vaccine.
The authors go on to discuss different potential strategies, including eliciting both T cell and B cell responses. Another interesting aspect of current HIV vaccine research is the area of vaccine evolution, as HIV sequences have tremendous diversity and mutation rates. This 'strength' of HIV can also be exploited as a 'weakness', because if we can better understand the constraints on HIV evolution, we can potentially force the virus down a particular evolutionary pathway, and thus back it into a corner - a corner in which we have the upper-hand. This 'evolutionary trap' vaccine is an exciting idea.
A final observation the authors make is that it is difficult for scientists outside the HIV field to get involved in HIV/AIDS-related research. Funding issues discourage many researchers from straying from their own areas of expertise. This causes a bottleneck to emerge, where it becomes progressively more difficult for 'fresh' labs to break into this area.
The authors conclude "We must finally apply the full power of modern science to the AIDS vaccine efforts, and by defining the knowable unknowns translate this knowledge to vaccine-mediated protection against a pathogen that has already caused over 30 million deaths and shows no sign of relenting."
Of course, if and when a HIV vaccine is developed, are we likely to encounter the same type of resistance espoused by McCarthy and her type towards the MMR vaccine?
Inevitably, the answer is yes.
Individuals are transient in the long-term, but ignorance is permanent.