Doctors may not need to restock the shelves as often with the tiny, clear bottles that hold vaccines.

Officials said more people are opting out of receiving vaccinations, something doctors say could have serious repercussions for the future.

“I think it’s always a concern that you have children in your community that are not vaccinated,” said Don Callaghan, the bureau chief for immunization at the Iowa Department of Public Health. “Diseases are always a plane ride away.”

According to the Annual Iowa Immunization Program report released by the Iowa Department of Public Health, the number of children receiving vaccines is decreasing.

In 2010, the number of 2-year-olds in Johnson County who received coverage of the entire vaccination series was at 59 percent. In 2011, that number dropped to 32 percent. Since then, it has hovered in the 30s, reaching 39 percent in 2012 and 37 percent in 2013.

Margaret Chorazy, an associate in the Department of Epidemiology at the University of Iowa College of Public Health, said young children are a focus when it comes to studying vaccination trends because it provides a clearer picture.

Callaghan said the fluctuation of a few percentage points is not worrisome, but that is not how Chorazy sees it.

Chorazy uses the idea of “herd immunity” to assess the issue. Herd immunity refers to the proportion of the community that is immune to the disease, either because they have had it before or have been vaccinated against it.  The higher the percentage, the lower the chance is of an outbreak of disease in that community.

“This is critically important because herd immunity also protects those individuals who are not vaccinated,” she said.

For example, Chorazy said up to 94 percent of the population must be vaccinated against highly contagious diseases, such as measles and whooping cough, to prevent an outbreak.

“In communities where the rates of vaccination for these diseases fall below the threshold for herd immunity, we’re more likely to see a return of these diseases in localized outbreaks that have the potential to spread to neighboring communities,” she said.

Nationally, the Centers for Disease Control and Prevention measured that 95 percent of the population was guarded against measles, mumps, and rubella in the most recent study, from 2012.

However, CDC spokesman Jason McDonald said it is impossible to measure for every area because there could be pockets and clusters of groups of people who choose not to vaccinate.

Chorazy said some people choose to opt out based on religious or philosophical beliefs, or because they feel they are uninformed or misinformed. 

“A legislative approach may also be warranted; the vaccine exemption laws in some states make it relatively easy for some parents to opt out of vaccines for their school-age children,” she said. “The hope is that parents who are on the fence about vaccinating their children will make their decision based upon accurate information about vaccines.”

Alan Phillips, an attorney who practices vaccine exemption and waiver law, said false representation and withholding of information is often a source of frustration, which could cause someone to opt out of the vaccination process.

“There is absolutely an increase in the number of people who are asking questions, who are expressing concerns,” he said. “Whether or not that has translated into the number of people who have asked for exceptions, I am unclear on that.”

Phillips, who lives in North Carolina but works with cases all over the country, said this issue is far from being solved.

“We will see an incredible fight,” he said. “The people who profit from [the business] don’t want to lose profits for this … so there is going to be tremendous resistance.”