A vaccine used to prevent tuberculosis in some parts of the world has been found to help prevent multiple sclerosis in people demonstrating early signs of the disease, according to a report published in Neurology.
Multiple sclerosis (MS) is notoriously difficult to diagnose, and many physicians rule out every other possibility before confirming the diagnosis. The initial symptoms are generally vague, with feelings of numbness, vision problems or problems with balance most often reported.
Doctors suspecting MS may suggest the patient have an MRI to see if there are any signs of the disease, but most will hold off confirming the diagnosis until other symptoms present themselves.
The researchers say that about 50% of people with these symptoms, called clinically isolated syndrome, will develop MS within 2 years, while 10% will show no more MS-related symptoms.
The study, which was supported by the Italian Ministry of Health, among other organizations, focused on 73 people who had experienced a single episode of MS-related symptoms.
For the study, 33 participants were given an injection of Bacille Calmette-Guérin (BCG), while the remaining participants were given a placebo. All the participants then had a brain scan once a month for 6 months and were then treated with the MS drug interferon beta-1a for a year.
Subsequent treatment was at the recommendation of their neurologist. The participants were followed for 5 years.
The brain scans of the vaccinated group showed fewer brain lesions that are characteristic of the disease than the group that received the placebo – three lesions on average, compared with seven.
And by the end of the study, 42% of the vaccinated group had developed MS, compared with 70% of the placebo group.
Although there were no adverse side effects, Dr. Giovanni Ristori, of Sapienza University of Rome in Italy, warns that more work needs to be done before this can be heralded as a cure:
“These results are promising, but much more research needs to be done to learn more about the safety and long-term effects of this live vaccine. Doctors should not start using this vaccine to treat MS or clinically isolated syndrome.”
In an accompanying editorial to the research paper, Dr. Dennis Bourdette, from Oregon Health & Science University in Portland and a Fellow of the American Academy of Neurology, writes that the results seem to support the “hygiene hypothesis.”
This suggests that better sanitation and the use of disinfectants and antibiotics in North America and much of Europe may account for some of the increased rates of MS and other immune system diseases, when compared with Africa and South America.
“The theory is that exposure to certain infections early in life might reduce the risk of these diseases by inducing the body to develop a protective immunity,” Dr. Bourdette says.