Widespread implementation of vaccines has dramatically reduced the incidence of many serious diseases and has improved the overall health of people in countries where they are routinely used. One of the most common vaccines is the MMR, which targets the measles, mumps and rubella viruses. Physicians administer the first dose of this vaccine to children when they are 12 to 15 months old. 

Researchers have studied whether the MMR vaccine is implicated in other diseases, most commonly autism and Inflammatory Bowel Disease (IBD). The scientific literature contains confusing, and sometimes contradictory, results.

What is a vaccine?

A vaccine causes your immune system to produce antibodies to suppress or kill infectious organisms that can cause disease. Antibodies are proteins in the immune system that bind to foreign objects, such as viruses, and play an important role protecting us against disease.

The MMR vaccine contains live, but weakened, versions of the measles, mumps and rubella viruses. It causes your body to build up immunity against these diseases. According to the Centers for Disease Control, the risk of harm from the MMR vaccine is very small.

Is there a link to Crohn's?

Some studies have reported an association between vaccines that contain the measles virus and an increased risk for IBD, although the role of measles infection in IBD is not yet clear. Measles is a highly contagious respiratory disease that can cause serious complications. It kills an estimated one million children worldwide every year, mostly in countries where the vaccine is not a routinely administered in early childhood.

Researchers in these studies report that the age at which children are exposed to the measles virus (through infection or vaccination) also seems to increase their risk for Crohn's disease. Children infected with the measles virus earlier in life are more at risk for delayed onset IBD. In one study, researchers concluded that the pattern of exposure to measles is a more important determinant of IBD than exposure alone.

There is another side to this issue, however. The results of other studies do not show a relationship between this vaccine and an increased risk for IBD. In fact, a report released by the World Health Organization states that there is clearly a lack of support linking measles vaccine and Crohn's disease.

Vaccine safety has been a contentious issue for several decades. The Vaccination Risk Awareness Network, for example, a nonprofit in Canada, believes vaccines have significant risks. The Network promotes full disclosure and informed consent for all vaccinations. This group, and others like it, will continue to push the issue and raise public concerns. Health organizations such as the Centers for Disease Control argue, however, that vaccinations are necessary to prevent serious and contagious diseases from creating a public health problem, and that their benefits far outweigh their risks.

If you have questions or concerns about vaccinations, discuss them with your physician, and continue to monitor the news. We're sure to hear a lot more about this topic in the months and years to come.











Dig Liver Dis. 2001 Aug-Sep;33(6):472-6.Related Articles, Links

Am J Gastroenterol. 2000 Jun;95(6):1389-92.