Despite compelling evidence of the value of vaccines in preventing disease and disability and in saving the lives of millions of children yearly, vaccine hesitancy has become a growing focus of attention and concern.1 Carrying out repeated surveys to track parental attitudes on the vaccination of their children is important to monitor barriers which may lead to suboptimal vaccination coverage.2 In the United States, data from the National Immunization Survey found a dramatic increase of parents delaying vaccines from 21.8% in 2003 to 39.8% in 2009, demonstrating the need to continually monitor and evaluate hesitancy using standardized instruments.3 Another U.S. national parental survey showed stability in acceptance and ongoing intentional delay of recommended childhood vaccines between 2012 and 2014.4
Israel has a high national average immunization coverage,5 and there is no mandatory vaccination. The aim of this study was to monitor vaccine confidence in Israel and to examine trends over time in attitudes and vaccine decisions among parents of young children.
MATERIALS AND METHODS
The study was conducted in October 2008 and in October 2016 by a subcontracted social research company, “Geokartography.” A representative sample of 360 parents of children 0–6 years of age was reached for each study. Data were collected by the computer-assisted telephone interview method. The methodology and sample sizes were determined to be identical for the 2 studies. The sampling was conducted randomly, keeping ratios for the attributes: sex, age of parents, age of children, religious orientation, and geographic area. The maximum statistical range of error related to this sample size is ±5.2%, at a statistical significance level of 95%.
Respondents were asked if they fully, partially or had not vaccinated their children. They were asked to rate their level of confidence in vaccine recommendations given by pediatricians and nurses and their opinion on the benefit versus risk of childhood vaccination. In the 2016 survey, parents were asked whether they delayed any vaccination of their child and what was the reason for that decision.
Parents were asked if they received antivaccination information and to rate their level of agreement with this information. They were also asked about hesitancy directed at specific vaccines.
Finally, parents were asked about their attitudes on a possible mandatory vaccination policy executed by a requirement for documentation of full vaccination before enrollment in kindergarten.
Responses to the questions that were asked in both 2008 and 2016 surveys were compared and analyzed. The study was approved by the Ethics Committee of Wolfson Medical Center, Israel.
In 2008, 90%, 9% and 1% of responding parents had fully, partially or not vaccinated their children, respectively. In 2016, the respective distribution was 89%, 9% and 2% of respondents. There was no significant change between the years (P = 0.62).
There was a significant drop in the level of parental confidence in vaccine recommendations given by pediatricians and nurses from 87% in 2008 (63% and 24% of respondents very highly and highly confident, respectively) to 72% in 2016 (41% and 31% very highly and highly confident, respectively) (P < 0.0001). Both in 2008 and in 2016 surveys, 78% and 82% of respondents confirmed that the benefits of vaccination outweigh the possible risks (P = 0.17).
In 2016, 27% of respondents reported that they had decided to delay vaccine doses for reasons other than allergy or fever. A significant change in the level of exposure to antivaccination information was documented between the years, rising from 44% of respondents in 2008 to 59% in 2016 (P < 0.0001). Agreement with the statement that vaccines can cause damage was expressed in 2008 by 43% of exposed to antivaccination information versus 27% of not exposed parents (P = 0.001) and in 2016 by 34% versus 23% of respective parents (P = 0.022). Fear of permanent damage as a result of vaccination was expressed in 2008 by 51% of exposed to anti vaccination information versus 32% of not exposed parents (P = 0.0019) and in 2016 by 54% versus 34% of respective parents (P = 0.0024).
A report of specific vaccines raising more parental hesitancy than others is presented in Table 1. Of notice, there is a significant increase in parental concern related to seasonal influenza vaccine while varicella vaccine is of less concern in 2016.
Seventy one percent of respondents in 2008 survey supported a requirement for documentation of full vaccination before enrollment in kindergarten, while in 2016, 66% of respondents supported such a policy (no significant difference between the 2 periods, P = 0.14).
The study demonstrates a stable and high reported acceptance rate of childhood vaccines both in 2008 and in 2016. This finding is consistent with a similar study in the United States demonstrating stability of vaccine reported acceptance from 2012 to 2014. This stability is also in accordance with the stable high national average childhood vaccination coverage.5
Parental vaccine refusal has been reported to be associated with less confidence in medicals sources for vaccine information.6 Our study demonstrated a decline of parental confidence in recommendations given by pediatricians and nurses between 2008 and 2016. Facing the stability of vaccine acceptance reported in our study, the decline in confidence apparently is not predictive of the decision to vaccinate. This is in contrast with the documented validity of the U.S. Parental Attitude about Childhood Vaccine survey7 to predict actual childhood immunization. A possible explanation might lie in the different methodology of the U.S. survey, where immunization data were taken directly from the children’s health medical records. However, decline in confidence may predict a future decline in actual vaccination coverage and calls for immediate actions from the medical establishment to revert this trend.
Changes in vaccination policy over time may cause a shift in parental concerns related to specific vaccines.8 In our 2008 survey, live varicella vaccine was reported to raise most of vaccine-related concerns, while in the 2016 survey, seasonal influenza, polio and HPV were responsible for most of the concerns.
In 2008, varicella vaccine was introduced into the Israeli National Vaccination Program. A study conducted in 2007 had demonstrated parental vaccine concerns to varicella vaccination, probably reflecting fears of the coming introduction into the program.9 It can be assumed that these concerns were reflected in our first survey in 2008. The absence of varicella vaccine concerns in the 2016 survey may demonstrate that years after a successful inclusion of a vaccine into the routine immunization program, the concerns decrease.
In 2009, the outbreak of pandemic H1N1 influenza caused a very vivid public debate concerning the vaccination, which provided fertile ground for hesitancy.8 It may be assumed that the seasonal influenza concerns raised in our 2016 survey were at least partially influenced by that event.
In 2013, the Israeli Ministry of Health has confirmed the reintroduction of wild-type poliovirus 1 into the country. After that event, there was a polio vaccination campaign in Israel, leading to an animated public debate and a clear evidence of hesitant behavior.10 It is possible that this event is responsible for a delayed hesitancy reaction toward this vaccine, which expressed itself in our 2016 survey, compared with a relative low hesitancy level regarding this vaccine in 2008.
The U.S. school immunization laws require vaccination for school and day care entry. Because of recent measles outbreaks in the United States and in Europe, several U.S. states have removed nonmedical exemptions from their school immunization laws, Italy passed in 2017 a new law to enforce mandatory childhood immunization and France is due to pass similar legislation in 2018.11 In Israel, the current policy is immunization recommendation policy. Our survey demonstrated a stable rate of two thirds of responding parents in favor of mandatory vaccination in 2008 and in 2016. The mandatory vaccination policy is controversial, and it is reasonable to assume that unless an infectious disease outbreak occurs in Israel, the current policy will not change despite an apparent public support for a change.
The main limitation of our study is that data regarding actual vaccination coverage were not taken directly from the children’s health medical records. However, the aim of our surveys was not to monitor the exact coverage of each vaccine but rather to examine the attitudes and concerns of Israeli parents and the trends in attitude along the years. While a higher number of responders may provide additional strength to the various trends demonstrated in our surveys, the number of responders was determined to be sufficient for representation of a national population.
We hope that these results may help health authorities to plan their strategies to increase vaccination coverage and minimize hesitance.
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