Nearly Half Of Kids Under Age Two Undervaccinated
January 22, 2013

Almost Half Of US Children Under Age Two Are Undervaccinated

Connie K. Ho for — Your Universe Online

A new study funded by the California-based health consortium Kaiser Permanente found that almost half of children under the age of two obtain vaccinations later than recommended, providing further evidence of what some health officials describe as a rise in the "undervaccination" of children.

The findings were recently featured in the Journal of the American Medical Association (JAMA) Pediatrics. Using information from the Advisory Committee on Immunization Practices schedule, the team of investigators discovered that 49 percent of children between the ages of two and 24 months did not obtain the recommended vaccinations or were not vaccinated at all.

The researchers referenced the Vaccine Safety Datalink (VSD), a project jointly completed by the U.S. Centers for Disease Control and Prevention (CDC) and nine other organizations to evaluate the immunizations records of 323,247 U.S. children. With the information pooled from the immunization records, the researchers were able to analyze the reasons children missed their schedule vaccines. Those who did not receive their vaccinations were labeled “undervaccinated.”

"While a large majority of parents in the US choose to vaccinate their children, a growing number of parents are concerned about vaccine safety and choose to vaccinate their children according to alternative immunization schedules," explained the study´s lead author Jason Glanz, a senior scientist who serves at Kaiser Permanente's Institute for Health Research, in a prepared statement. "The medical community doesn't have a lot of data on these alternative schedules, so we are hoping the results from this study will open the door to more opportunities to examine their safety and efficacy."

The alternative immunization schedules described by Glanz refer to an increased amount of time between vaccinations or a decrease in the number of vaccinations during one doctor visit. With alternative schedules, children can be left undervaccinated. Furthermore, children who are undervaccinated have a lower likelihood of visiting their doctor´s office on a regular basis and have a greater possibility of being admitted to a hospital as compared to other children who received the recommended number of vaccinations.

In addition to simply finding out the number of children who were undervaccinated, the team of investigators also wanted to determine the reasons why they did not obtain their vaccinations. During their research, they found that one of the reasons children went unvaccinated was that their parents purposely chose not to have their children receive vaccines. The authors reported that this was the case in one of every eight children.

“Undervaccination appears to be an increasing trend. Undervaccinated children appear to have different health care utilization patterns compared with age-appropriately vaccinated children,” wrote the researchers in the paper.

An editorial by Dr. Douglas J. Opel and Dr. Edgar K. Marcuse also accompanied the study on alternative schedules and undervaccinated children. The two authors pondered the questions related to the issue, and noted that it is important to consider the risk related to alternative schedules.

“The dominant issue is whether any alternative schedule adequately protect as child — and thereby the child´s community — from each of the vaccine-preventable diseases, so it therefore seems essential to answer the first question first. Only after it is proven that an alternative schedule does not substantially increase the risk of an individual acquiring a vaccine-preventable disease does it seem reasonable to study that schedule´s safety profile,” commented the authors in the editorial.

Following this study, Kaiser Permanente hopes to continue to look at vaccine effectiveness and safety. They are also interested in studying vaccine refusal. In particular, recent studies on vaccine refusal showed that children of parents who refuse vaccines are nine times more likely to suffer from chickenpox and 23 times more likely to suffer from whopping cough than children who have been fully immunized.