A Vaccine for Obesity?
There has been some buzz recently about an anti-obesity vaccine that is currently being developed. This is the result of a new look at obesity, seeing it as a result of disease rather than lifestyle choices, such as the view adopted in a 2007 review by A. Vasilakopoulouand C. W. le Roux of Imperial College, London, which suggested that in some cases, obesity could be caused by viruses.
The study examined a number of potential obesity-causing viruses. First among these was the canine distemper virus, which affects a wide range of carnivores and is extremely contagious. However, although the researchers found evidence to links the virus to obesity in mice, they found none linking it to obesity in humans.
More interestingly, the researchers also examined Rous-associated virus 7 (RAV-7), an avian virus that causes obesity in chickens. Viruses of this type effect a large number of commercial chicken and eggs, which means that those of us who eat commercial poultry products are exposed to these viruses on a regular basis. Even more worrying, some human viral vaccines, including that for measles, mumps, and rubella (MMR), are manufactured by growing the vaccine-virus in chicken eggs that may carry avian viruses like RAV-7. The results of human exposure to RAV-7 are still unknown.
Borna disease is yet another virus that may be linked with obesity. This time, the virus is a neurological disease affecting mainly horses and sheep, although there have been reports of the infection in cattle, dogs, cats, rabbits, and even zoo animals. The virus may be linked with psychiatric disorders in humans, including schizophrenia and obsessive compulsive disorder. As before, however, borna disease has not been linked to human obesity.
Other diseases examined in the study are scrapie disease, a fatal degenerative virus attacking sheep and goats; SMAM-1 virus that affects chickens; and human adenoviruses. The SMAM-1 virus in particular has been shown in at least one case to be associated with human obesity: researchers have found that obese people were three times more likely to have antibodies present to the avian virus, and the review concluded that a virus-based theory of obesity is worthy of more investigation.
There may be a clear link between the animal viruses named above and human obesity. One has to wonder whether vaccines are one way in which humans are being exposed to these obesity-causing viruses – the SMAM-1 virus, like RAV-1, affects chickens, and as mentioned above, certain vaccines are manufactured using viruses grown in chicken eggs that may carry obesity-causing viruses.
This is a new explanation for obesity that requires further study, but it seems that this research may be have been bypassed given the new anti-obesity vaccine that has been developed, which relies on a hormone-based mechanism to decrease food intake by suppressing the appetite. This vaccine was only tested on mice for two months, long-term effects on humans are unknown; and as our research shows, it may treat only the symptoms, not the causes of obesity.