Half of parents concerned about vaccine side effects

Mar 1, 2010 (CIDRAP News) – About half of the parents responding to a national survey say they are concerned about adverse effects of vaccines, and one in four believe some vaccines cause autism, according to a paper published today by the journal Pediatrics.

 But at the same time, 90% of the same parents agreed that receiving vaccines is a good way to prevent diseases in their children, and 88% said they follow doctors' recommendations of which vaccines to get.

The survey of 1,552 parents by University of Michigan researchers in medicine and public policy was conducted in January 2009, before the H1N1 epidemic, and also before the withdrawal of the 1998 Lancet article that incorrectly found a link between autism and the measles-mumps-rubella (MMR) vaccine.

"We were pleasantly reassured that 90% of all parents believe vaccines are a good contribution to the health of their children," lead author Gary Freed, MD said in an interview. Freed is director of the Child Health Evaluation and Research unit at University of Michigan Medical School. "But it's sobering that one in four believe that vaccines can cause autism in otherwise healthy children."

The survey results demonstrate that parents' questioning of vaccines varies by gender, ethnicity, and also by which vaccine is under discussion. Women were more likely than men to be concerned about serious adverse events and also to believe that vaccines cause autism. Hispanic parents were more likely than whites or blacks to accept the vaccines-autism claim.

Overall, 11.5% of parents said they had refused at least one vaccine recommended by their doctor. The most commonly refused vaccine was for human papillomavirus (HPV), followed by varicella (chickenpox), the meningococcal conjugate vaccine, and MMR. But they were not all refused for the same reason.

The most common reasons why HPV was refused, for instance, was because parents believed the vaccine had not been thoroughly researched (78%) and had not been on the market long enough (75%). For the meningococcal vaccine, however, the lead reason was that parents believed the risk of adverse events to be too high (72%); and for varicella, that parents would rather the child caught the disease and acquired immunity via the infection (78%). Half of parents (51%) also objected to HPV vaccine for "moral or ethical concerns."

That different vaccines were distrusted for different reasons may paradoxically be good news, the authors said, because it shows that opposition to vaccination is not monolithic. Rather, it demonstrates that parents have specific concerns that public health messages could be tailored to.

Distrust of the degree to which vaccines are tested was a theme in the study: Only 51% of parents agreed that "new vaccines are recommended only if they are as safe as older vaccines."

"I think it is important for health professionals to say to parents how thoroughly vaccines are tested before they are ever put on the market," Freed said. "I think parents are unaware of how extensive that testing really is, and that may help to alleviate some of their fears."

Freed GL, Clark SJ, Butchart AT, et al. Parental vaccine safety concerns in 2009. Pediatrics 2010 (published online Mar 1) [Abstract]

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