More and more parents in one area of Oregon are not following the recommended vaccination schedule for their babies and that means some are missing their recommended shots, according to a new study.
Researchers found that the number of babies on alternative vaccination schedules grew from 2.5 percent in 2006 to 9.5 percent in 2009. And despite going to the doctor's office more, those babies got fewer shots overall compared with those whose parents stuck to the recommended schedule.
Delaying or avoiding shots through alternative schedules have known risks -- such as increasing the amount of time babies are susceptible to certain disease -- but no known benefits, according to the authors from the Oregon Health Authority and the U.S. Centers for Disease Control and Prevention (CDC), who published their study in the journal Pediatrics on Monday.
"The findings are not surprising, but they're troubling," said Dr. Saad Omer, an assistant professor at Emory University in Atlanta.
Omer, who was not involved with the new study, said past research showed that some parents reported plans to not follow the recommended vaccine schedule. These numbers, he said, show those parents acted on those plans.
The 2009 Oregon figures are similar to those in a 2011 study of the entire U.S., which found more than one in ten parents used an alternative schedule, or refused vaccines altogether (see Reuters Health story of October 3, 2011).
The researchers say the delay can be from a fear of too many shots all at once, pain, questioning whether some vaccines are necessary and a general mistrust of the government and industry.
The CDC-backed Advisory Committee on Immunization Practices (ACIP) recommends babies get a series of shots before their first birthday. That schedule is backed by the American Academy of Family Physicians and the American Academy of Pediatrics. The shots offer protection against several diseases, including diphtheria, whooping cough, polio, tetanus and the flu.
"The recommended schedule is based on indisputable scientific evidence that the vaccines will work to prevent infections and are safe," wrote Dr. Carol Baker, ACIP's chair and a professor of pediatrics at the Baylor College of Medicine in Houston, in an email to Reuters Health.
And while the study cannot say if more of the "shot limiters" are getting sick compared to the others, Steve Robison, the study's lead author from the Oregon Immunization Program, said their previous research suggests that's the case -- especially looking at studies of pertussis cases, also known as whooping cough.
To see how many parents followed alternative vaccination schedules, researchers used shot records for all babies born in and near Portland between 2003 and 2009.
Of the 97,711 children born in that time period, about 4,500 received two shots or less at every immunization visit to the doctor's office before they were nine months old. Those kids were called "consistent shot limiters."
The two-shot definition, according to the researchers, is based on published alternative schedules such as those by Dr. Stephanie Cave and Dr. Robert Sears in their respective books. There was a slight decline in the percent of "shot limiters" between July 2003 and October 2006. Then, there was a steep increase until October 2008, when the percentages remained steady until the end of the study. The data can't explain the reason behind the dramatic increase.
On average, shot limiters received about six vaccinations across about four visits to the doctor's office. Those who stuck to the schedule -- or only missed a shot here and there -- received about 10 vaccinations across about three visits. That difference was significant, according to the authors, and the "shot limiters" still didn't catch up to the rest even at 19 months of age.
"The problem that we saw is that these kids are getting fewer shots total and they're not catching up," said Robison.
"Parents and doctors don't realize how easy it is for kids on alternative schedules to fall behind," he added.
Dr. Paul Cieslak, the Oregon Immunization Program's medical director, said the ACIP schedule is designed to balance the number of vaccinations needed with the realities of a parent taking time off work and scheduling doctor visits.
"If you're getting your kid vaccinated according to schedule, good work… If you're tempted to use these alternative schedules, your child is going to be more susceptible (to the diseases) for a longer period of time," he said.
Dr. Amanda Dempsey, of the Children's Outcomes Research Program at the University of Colorado, Denver, told Reuters Health there are other problems beyond health concerns. Dempsey, who was not involved with the new study, told Reuters Health that alternative schedules add an extra burden to the healthcare system by increasing the number of doctor visits that add to the stress of parents and babies.
She said there is also a danger that the wider population will lose "herd immunity," which is when some people -- including sick people and infants -- are protected because the people around them are immune.
"No vaccine is 100 percent effective. So even if you had all your vaccines, if you're surrounded by people who are carrying diseases, you're at risk," she said.
Robison told Reuters Health that the people included in this study have a high rate of exemptions for school-required vaccines and the findings may not apply to other areas. Another limitation of the study is that it relies on doctors reporting information. But overall, the results are bad news for children and infants, wrote Baker, who was not involved with the new study.
"These limiter parents are gambling with the health of their children; parents should be able to make medical choices but I pray they will make the best choices, and not following the schedule is the wrong choice."