Unvaccinated clusters of students may increase outbreak chances

Clusters of unvaccinated children in approximately 200 Illinois schools may be raising the chances of school-based outbreaks of serious preventable diseases like whooping cough and measles.

An analysis by the Chicago Tribune found that the amount of schools falling below 90 percent immunization for the measles rose from 31 in 2003 to 124 in 2010. For polio, the numbers rose from 27 in 2003 to 122 in 2010. Ninety percent immunizations is the protection level the state recommends to prevent epidemics, the Chicago Tribune reports.

A lack of vaccination is sometimes the result of low-income students who do not have proof they are up-to-date with immunizations while others are private schools serving middle class and wealthy families who sometimes seek religious exemptions from vaccination requirements. In some schools, immunization rates fell below 60 percent against some diseases.

"Whenever the community risk goes up, everyone tends to get affected, including people who are vaccinated," Saad Omer, an Emory University scientist who researches unvaccinated clusters, said, according to the Chicago Tribune. "Even the best vaccines are not perfect."

Omer said that a cluster of unvaccinated people is like a small patch of dry grass that can catch fire and spread through the rest of the grass.

"Despite high overall … compliance levels, outbreaks can still occur when clusters of unvaccinated children congregate together in school and community settings," Karen McMahon, the Illinois Department of Public Health's vaccination section chief, said, according to the Chicago Tribune. "Childhood diseases are still very prevalent in the world and can be brought to the U.S. — therefore, vaccination is important."

Diseases like measles and pertussis have recently begun to make a comeback as a result of the weakened herd immunity that comes with more and more parents neglecting to vaccinate their children for whatever reason.

"Individuals, if they look at the world selfishly, will say, 'I don't want a needle to be stuck into my kid, but I want everyone else to be vaccinated,'" Dr. Paul E.M. Fine, a community immunity expert and professor of communicable disease epidemiology at the London School of Hygiene and Tropical Medicine, said, according to the Chicago Tribune. "There is a brutal, ugly logic there."