COLUMBUS, Ohio (WTVN) -- The number of Ohio parents opting against having their children vaccinated for religious or philosophical reasons has increased five-fold since 1997. Students in Ohio are required to be vaccinated before they go to school, but there are exemptions for medical or religious reasons.

Last year 3,700 students used a religious or philosophical exemption. Only 740 did in the 1997-98 school year. However, it is still less than 2 percent of the entire K-12 student population in Ohio.

"We are concerned, there are some pockets, we believe, where there are some lower vaccination rates, but in general across the whole state we have good immunization rates," said Dr. Mary Diorio, the state epidemiologist with the Ohio Dept. of Health.

The state's vaccination rates have bounced between the high 80s to low 90s over the past 15 years.

If the number of exemptions get too high it can be a problem. That's because some children who can't get vaccinated for medical reasons won't be able to benefit from other students being immune to diseases.

"If you have a large number of individuals who are vaccinated disease is less likely to spread through that community," Diorio said.

One disease that is of greatest concern is pertussis, or whooping cough. Diorio says that's because over time the vaccine wears off, requiring a booster. There have been recent outbreaks of pertussis in Ohio.

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