The Biggest Influence on a Mother's Decision to Vaccinate Her Child May Surprise You

When given negative information on vaccines from friends and family members, one study has found that pregnant women were more likely not to have their children vaccinated on time, even after receiving positive information from their doctors.

For the study, published in the journal, Pediatrics, researchers analyzed data from a cohort of 6205 children from New Zealand’s (NZ) child cohort study—Growing Up in New Zealand (www.growingup.co.nz)—scheduled to be born between April 25, 2009, and March 25, 2010. The authors state that, “11% of all children born in NZ during the recruitment period were enrolled. The enrolled cohort is generalizable to all births in NZ from 2007 to 2010. For the 168 multiple births in the cohort, [the authors] only included the first-born child in these analyses. For all but 3 sets of twins or triplets, immunization coverage and timeliness were identical between twin or triplet siblings.”

A total of 6822 mothers were interviewed face-to-face via computer assistance at 39 weeks’ gestation (median gestation time) and asked to describe their “sources of information encouraging or discouraging infant immunization,” according to the study. They determined the immunizations that the children received through the National Immunization Register, and “independent associations of immunization information received with immunization timeliness were described by using adjusted odds ratios (ORs) and 95% confidence intervals (CIs).”

Ninety-one percent of the pregnant women who were interviewed described their information sources. About 56% of the women who described their sources indicated that they did not receive any information about vaccines while they were pregnant, while the remaining women reported receiving information as follows: 30% received information encouraging immunization, 4% received information discouraging immunization, and 10% received both encouraging and discouraging information.

Regarding the sources of the information, 14% of the women reported receiving information from family and friends, 35% from healthcare providers, 14% from the media, and 2% from other sources. Ninety percent of the women who identified healthcare providers as their source of information reported that they received only encouraging information. Conversely, of those who identified family and friends as their source, only 39% reported receiving only positive information, and, “53% of those identifying media sources received only encouraging information,” according to the study.

Of note is the fact that some women received discouraging information from healthcare providers. Co-author, Cameron Grant, MD, PhD, head, department of pediatrics, child and youth health, University of Auckland, and pediatrician, Starship Children's Health, Auckland, New Zealand, remarked on this in a press release on the study, stating, “it was concerning that 1 in 6 women who recalled receiving discouraging information, identified healthcare providers as a source of that information.”

When reporting the immunization timeliness of the children based on the type of information their mothers received, the authors reported, “compared with infants of women who received no immunization information (71% immunized on-time), infants of women who received discouraging information only (57% immunized on time, OR = 0.49, 95% CI 0.38—0.64) or encouraging and discouraging information (61% immunized on time, OR = 0.51, 95% CI 0.42–0.63) were at decreased odds of receiving all immunizations on time. Receipt of encouraging information only was not associated with infant immunization timeliness (73% immunized on time, OR = 1.00, 95% CI 0.87–1.15).”

Dr. Grant remarked on these results in the press release, stating that he was, “surprised and disappointed that encouraging information had no positive influence,” as evidence by the similar rates of on-time immunizations in both the encouraged and ‘no information’ groups. However, those women who received both types of information, or only negative information can be educated further to yield better results.

To this end, Dr. Grant added, “We have to do a particularly better job of encouraging immunization for the infants of future parents who have received discouraging information about immunization.” In an email interview with Contagion^®, Dr. Grant provided some suggestions on how practitioners can improve their methods through the following techniques, stating that practitioners should, “discuss infant immunization with every future parent: both the moms and their partners. The partners are important. A larger proportion of them are undecided about infant immunization before the child is born and so they need to be better informed. [In addition,] ask future parents what information they have already received and specifically if they have received any discouraging information. If they have received discouraging information, discuss this with your patients and ensure that you answer all questions, concerns, and uncertainties that this information has caused in the parents.”

Paul Offit, MD, director, Vaccine Information Center, the Children's Hospital of Philadelphia, acknowledged in the press release that this is easier said than done. “It's much easier to scare people than to unscare them. The autism story proves that,” referring to “one poorly done study that was later retracted led to 17 studies in seven countries, costing tens of millions of dollars that showed no greater risk of autism in kids who received the measles, mumps and rubella (MMR) vaccine.”

According to Dr. Offit, younger physicians who have never seen or experienced many of the diseases vaccines protect against may also contribute to the lack of urgent necessity to receive vaccines on time.

“I'm an older physician. I've had measles. I've had mumps. Today, if a child comes in with one of those diseases, younger doctors haven't seen it and often call for me to confirm the diagnosis," Offit said in the press release. "So, young doctors may not be as compelled to argue for vaccines. They haven't seen these diseases, so they may not be great advocates for vaccines.”

When Contagion^® asked Dr. Grant what could be done to help assuage this issue, he remarked that young practitioners are “fortunate not to have seen [these infections] because they are horrible diseases and watching children experience them is distressing; [however,] there are excellent resources available [for these practitioners] through the American Academy of Pediatrics which describe these diseases very graphically.”