The once hotly-debated idea that some childhood vaccines can cause autism has been thoroughly debunked. However, a new study suggests that parents of young children remain unconvinced that the recommended schedule of vaccines is safe and appropriate.
The study comes at a time when the nation is experiencing a resurgence in infectious diseases that were once largely tamped down, including pertussis, measles, and mumps. And it indicates that the federal government will face a huge challenge in its mission to improve child immunization rates.
The study, published this week in JAMA Pediatrics, analyzes immunization data from 323,247 children in nine managed care organizations born between 2004 and 2008. Data from immunization records was analyzed, including the number of days each child was missing scheduled vaccines for any reason. Immunization was considered delayed if the child hadn't received the vaccine within 30 days after the recommended date, such as 2 months of age or five years old.
The reasons children miss immunizations or fall behind—what’s called “under-vaccination”—are many, the lead study author Jason Glanz, a senior scientist at Kaiser Permanente's Institute for Health Research, told TakePart. Sometimes, children are ill or parents are just too busy to take their child into the doctor's office or to a clinic.
Some families lack the basic funds to pay for transportation to the doctor or a minimum fee, although the children in this study were covered by insurance.
But many other parents, Glanz says, choose to delay their kids' vaccinations. "Most parents get their [children’s] vaccines on time. But a lot of parents are choosing these alternative schedules that we don't know are as safe," he says. "What is concerning is the trend. The trend suggests that more parents are intentionally intending to do this."
The study showed that the number of under-vaccinated children increased significantly over the study period -- from 41.8 percent in 2004 to 54.4 percent in 2008. Researchers estimate that about 13 percent of the children were under-vaccinated because their parents chose to delay vaccinations or opted for alternative schedules that increased the time between vaccinations or reduced the number of vaccinations given at one office visit.
But, they added, that number most likely underestimates the parents who choose to delay vaccination. "These aren't parents who are outright rejecting vaccinations," Glanz says. "They want to prevent their kids from getting a disease, but they are concerned about safety. One common expression we hear is 'too many too soon.'"
According to the child immunization schedule published by the Centers for Disease Control and Prevention (CDC), children get about 25 separate doses of various vaccines by the age of six, not counting an annual flu shot. The child vaccine schedule has expanded greatly over the past two decades due to medical advances that have produced protection for hepatitis A and B, rotavirus, and chicken pox.
But some parents may just see lots of shots.
“It's a complicated issue," Glanz says. "Number one, we've been so successful at eliminating these diseases that we don't see them anymore. Naturally, parents are going to focus on safety. I understand that because drugs tend to be given to people who are already ill. Vaccines are given to healthy kids. So adverse events aren't acceptable. It makes sense for parents to be concerned about safety."
However, it's not clear whether these parents are inadvertently compromising their children's safety by delaying immunizations. The CDC recommends certain vaccines at specific ages in order to maximize the safety and effectiveness of the vaccines. "The shots are given when children are the most vulnerable to disease and when the body responds the best," Glanz says. "We don't know if deviating from this schedule is as safe, less safe, or more safe than the current schedule."
But, he adds: "The longer you delay these vaccines, the greater the likelihood a child will contract a vaccine-preventable disease."
Recent Kaiser Permanente studies found that children of parents who refuse vaccines are nine times more likely to get chickenpox and 23 times more likely to get whooping cough than fully-immunized children. Under-vaccinated children are less likely to visit their doctor's offices and more likely to be admitted to hospitals compared to their peers vaccinated under the standard schedule.
Doctors may need to spend more time with parents to reassure them of the safety of the CDC's vaccine schedule, Glanz says. Moreover, research is needed to explore whether the "alternative" vaccine schedules that delay some shots are safe.
"Under-vaccinated is becoming more common, and it's being accommodated more," Glanz says. "I think that if we continue to accommodate parents in this way, the national recommended schedule will start to lose its meaning. That is the danger."
Do you think the recommended child immunization schedule is safe? Have you adopted an “alternative schedule” for vaccinating your child?
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Shari Roan is an award-winning health writer based in Southern California. She is the author of three books on health and science subjects.