A recent internet survey which included 748 parents of kids between six months and six years old. Of those, 13 percent said they used some type of vaccination schedule that differed from the CDC recommendations. That included refusing some vaccines or delaying vaccines until kids were older -- mostly because parents thought that "seemed safer." In addition, two percent of parents refused any vaccination altogether, according to findings published in Pediatrics.
The survey, conducted by researchers at the University of Michigan in Ann Arbor, evaluated 748 responses. The parents ranged from 18 to 59 years old, but most were ages 30 to 44. The results were comparable to an earlier, larger study by the CDC.
Parents were most likely to skip vaccination against H1N1 (swine flu) and seasonal flu, the study says. Parents were least likely to skip the polio vaccine. Researchers also noted that white parents were more likely to follow an alternate vaccine schedule, as were families who didn't have a regular doctor.
The patterns among those not following the recommended schedule varied. Among them:
- 17% said their child did not get any vaccines.
- 53% said they didn't get some vaccines.
- 55% said they delay some vaccines until older than the recommended age.
- 36% said they wait longer between multiple-dose vaccines than is recommended.
- 22% said they got each part of the measles, mumps and rubella vaccine separately.
- H1N1 influenza, refused by 86% of those on the alternative schedule
- Seasonal influenza, 76%
- Chickenpox (varicella), 46%
That, in turn, can create what he calls a ''critical mass" of people to trigger a disease outbreak.
"There is a reason why there is a schedule," says Omer. "The risk of preventable disease is not constant. One of the reasons we give vaccines at a certain age is the children are vulnerable at a certain age."
Another problem, he says, is that as parents spread out the vaccinations, the risk of not completing the recommended ones increases.
The CDC maintains a schedule of recommended vaccines on its web site, www.cdc.gov/vaccines/recs/schedules/child-schedule.htm