Accepted Manuscript Prevalence of Vaccine Hesitancy Among Expectant Mothers in Houston, Texas Rachel M. Cunningham, MPH, Charles G. Minard, PhD, Danielle Guffey, MS, Laurie S. Swaim, MD, Douglas J. Opel, MD, MPH, Julie A. Boom, MD PII:

S1876-2859(17)30461-8

DOI:

10.1016/j.acap.2017.08.003

Reference:

ACAP 1074

To appear in:

Academic Pediatrics

Received Date: 24 February 2017 Revised Date:

26 July 2017

Accepted Date: 1 August 2017

Please cite this article as: Cunningham RM, Minard CG, Guffey D, Swaim LS, Opel DJ, Boom JA, Prevalence of Vaccine Hesitancy Among Expectant Mothers in Houston, Texas, Academic Pediatrics (2017), doi: 10.1016/j.acap.2017.08.003. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Prevalence of Vaccine Hesitancy Among Expectant Mothers in Houston, Texas Rachel M. Cunninghama, MPH, Charles G. Minardb, PhD, Danielle Guffeyb, MS, Laurie S.

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Swaimb,c, MD, Douglas J. Opeld,e, MD, MPH, Julie A. Booma,b, MD Affiliations: aTexas Children’s Hospital, Houston, TX; bBaylor College of Medicine, Houston, TX; cTexas Children’s Pavilion for Women, Houston, TX; dSeattle Children’s Research Institute;

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and eUniversity of Washington School of Medicine, Seattle, WA Authors:

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Rachel M. Cunningham, MPH, Immunization Project, Texas Children's Hospital, 1102 Bates Ave., Suite 1550, Houston, TX 77030, [email protected], 832-824-2010. Charles G. Minard, PhD, Institute for Clinical and Translational Research, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, [email protected].

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Danielle Guffey, MS, Institute for Clinical and Translational Research, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, [email protected]. Laurie S. Swaim, MD, Division Gynecologic and Obstetric Specialists, Baylor College of

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[email protected].

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Medicine, Texas Children’s Pavilion for Women, 6551 Main St., Houston, TX 77030,

Douglas J. Opel, MD, MPH, Seattle Children’s Research Institute, University of Washington School of Medicine, 1900-9th Ave. Seattle, WA 98101, [email protected]. Julie A. Boom, MD, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Ave., Suite 1550, Houston, TX 77030, [email protected].

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Address correspondence to: Rachel Cunningham, 1102 Bates Avenue, Suite 1550, Houston, TX 77030, [email protected], 832-824-2010 (phone), 832-825-2103 (fax) Keywords: vaccine hesitancy, pregnancy, vaccine, Parental Attitudes About Childhood

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Vaccines survey

Running title: Prevalence of Vaccine Hesitancy Among Expectant Mothers Abstract word count: 250

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Main text word count: 2594

Funding source: No external funding was secured for this study.

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Financial Disclosure: The authors have no financial relationships relevant to this article to disclose.

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Conflict of Interest: The authors have no conflicts of interest relevant to this article to disclose.

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Objective Non-medical exemptions continue to rise due to increasing proportions of vaccinehesitant parents. The proportion of expectant parents who are vaccine-hesitant is currently

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unknown. We assessed the prevalence of vaccine hesitancy among expectant parents receiving care at an obstetrics clinic in Houston, Texas. Methods

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We conducted a cross-sectional survey of expectant parents between 12 and 31 weeks gestation who received care at Texas Children’s Pavilion for Women between July 2014 –

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September 2015. Using convenience sampling, participants completed a questionnaire that included demographic items, self-assessed pregnancy risk, receipt of annual influenza vaccine and the 15-item Parents Attitudes about Childhood Vaccines (PACV) survey, a validated tool to identify vaccine-hesitant parents. We used multivariable logistic regression to determine the

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association of demographics, pregnancy risk, and influenza vaccine receipt with vaccine hesitancy after controlling for variables significant in univariable analyses. Results

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610 expectant mothers and 38 expectant fathers completed the PACV. Overall, 50 of 610 expectant mothers (8.2%, 95% CI: 6.1%, 10.7%) were vaccine-hesitant. Expectant mothers were

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primarily non-Hispanic White, ≥30 years old, and married. The odds of being vaccine hesitant were 2.2 times greater (95% CI: 1.2, 4.1) among expectant mothers with a college level of education or less compared with those with more than a 4-year degree. The odds of being vaccine-hesitant were 7.4 times greater (95% CI: 3.9, 14.0) among expectant mothers who do not receive an annual influenza vaccine compared with those who did.

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Conclusion

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Our findings suggest the need to identify and address vaccine hesitancy prior to birth.

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What’s New: This cross-sectional survey administered at a single obstetric clinic in Houston, Texas is the first to assess vaccine hesitancy among expectant mothers. We found 1 in 12 expectant mothers to be

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vaccine hesitant.

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Abbreviations: VHP: vaccine-hesitant parent PACV: Parental Attitudes About Childhood Vaccines survey

PABAK: probability-adjusted bias-adjusted kappa statistic

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Introduction

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BCM OB/GYN: Baylor College of Medicine Obstetrics and Gynecology

Vaccine coverage in the U.S. remains high.1 However, the number of non-medical

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exemptions continues to rise.2-3 Children who are un- or under-vaccinated due to parental vaccine refusal or delay can contribute to outbreaks of vaccine-preventable diseases.4-7 Therefore, addressing parental vaccine concerns in order to maintain high vaccine coverage levels is essential to individual and public health.

Vaccine-hesitant parents (VHPs), defined as parents who are unsure about accepting

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vaccination, purposefully delay vaccines, or choose only some vaccines, are of particular interest. Since VHPs generally trust their child’s pediatric provider and seek vaccine information before deciding whether or not to vaccinate, they may be more amenable to behavior change than

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parents who refuse all vaccines.8-11 Given the important role of pediatric providers in the vaccine

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decision-making of VHPs, increased attention has been paid to having other healthcare providers discuss vaccines with expectant parents, in particular, prenatal providers.12 However, the proportion of expectant parents who are vaccine-hesitant is currently unknown. The primary objective of this study was to assess the prevalence of vaccine hesitancy among expectant mothers receiving care at a tertiary care obstetrics clinic in Texas. Secondary objectives were 2fold: 1) to characterize the demographics, pregnancy characteristics, and receipt of an annual

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influenza vaccine among vaccine-hesitant expectant mothers, and 2) to compare vaccine hesitancy between expectant mother and co-parent pairs. Methods

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Setting and sample

We conducted a cross-sectional survey study of English-speaking expectant parents seen at the Baylor College of Medicine Obstetrics and Gynecology (BCM OB/GYN) practice at the

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Texas Children’s Pavilion for Women, an urban, tertiary women’s hospital in Houston, TX with 2,152 deliveries during the study period. Expectant parents (including fathers and co-parents)

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were eligible if they were English-speaking, the pregnant parent was between 12 and 31 weeks gestation, both parents were ≥18 years old, and neither parent participated in any prior vaccine study that occurred at the study institution. We identified potential participants using the clinic’s daily schedule. A study team member approached parents in the waiting room following

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appointment check-in from July 2014 to September 2015 using convenience sampling. All participants provided written informed consent to be surveyed. We linked co-parents to the expectant mother, and participating parents completed the Parental Attitudes About Childhood

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Vaccines (PACV) survey before the end of their appointment. The Institutional Review Board at Baylor College of Medicine reviewed and approved this study.

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Data collection

In the absence of an instrument specifically designed to identify vaccine-hesitant

expectant parents, we modified the PACV survey, a validated tool for identifying vaccinehesitant parents, for use in the expectant parent population (Figure 1).11, 13-15 Previous evaluations of the PACV demonstrated construct and predictive validity by associating higher total PACV scores with under-vaccination.11, 13 The PACV survey is self-administered, contains 15 items

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under 3 domains (behavior, safety and efficacy, and general attitudes), and reads at a 6-7th grade level. We modified the PACV for use among expectant parents in the following minor ways: 1) we changed the PACV item “If you had another infant today, would you want him/her to get all

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of the recommended shots?” to read “Do you want your baby to get all the recommended

vaccines?” to prevent confusion among expectant parents from pregnancy or neonate-related injections such as RhoGAM® or Vitamin K; and 2) we directed expectant parents to skip the 2

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PACV items which sought to identify previous behaviors related to vaccine delay or refusal if this was their first pregnancy.

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We also asked parents to provide demographic information and self-assessed pregnancy risk at the time of completing the modified PACV. Parental demographic information included age, gender, educational level, marital status, race or ethnicity, household income, relationship to expectant child, number of children in the household, and whether the expectant child was the

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firstborn. We assessed pregnancy risk by asking the expectant parent(s) to self-report if their pregnancy was complicated by any one of the following: diabetes, preterm labor, obesity, seizure disorder, advanced maternal age (>34 years), hypertension, short cervix, placenta previa,

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multiple gestation (ex: twins, triplets), asthma, history of preterm labor, fetal anomaly, autoimmune disorder (ex: lupus, rheumatoid arthritis), and other (open response allowed).

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Lastly, given data demonstrating that parents who receive prenatal influenza vaccines are more likely to receive subsequent vaccines for their child, we asked whether the parent received annual flu shots.16 Data analysis

We scored the PACV using the method previously established by Opel et al.11 Briefly, we scored the 15 PACV item responses as either non-hesitant, not sure, or hesitant and assigned a

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numeric score of 0, 1, or 2, respectively. For items with a 5-point Likert-scale ranging from ‘strongly agree’ to strongly ‘disagree’, responses of either ‘strongly agree/agree’ or ‘strongly disagree/disagree’ scored as hesitant. For items with a 5-point Likert-scale ranging from ‘not at

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all concerned’ to ‘very concerned,’ responses of either ‘very concerned’ or ‘somewhat

concerned’ scored as hesitant. Responses of ‘not at all’ or ‘not too concerned’ scored as nonhesitant. Affirmative responses to yes/no items scored as hesitant in all but one item which

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asked, “Do you want your baby to get all of the recommended vaccines?” For this item, the negative response scored as hesitant. For items with an 11-point Likert-scale, responses 0-5, 6-7,

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and 8-10 scored as hesitant, not sure, and non-hesitant, respectively. Lastly, for the two behavior related items that sought to identify previous vaccine delay or refusal among expectant parents with other children, we excluded responses of ‘don’t know’ or ‘not sure’ as missing data and adjusted PACV scores accordingly for those participants. This was consistent with previous

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studies conducted by Opel et al. who attributed these responses to poor recall rather than vaccine hesitancy.11 We generated an unweighted score to obtain a raw total PACV score which we then converted to a 0-100 point scale using simple linear transformation to improve PACV score

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interpretation, consistent with the original scoring method. Final PACV scores were dichotomized as ≥50 (hesitant) and 99% probability of estimating the proportion of vaccine-hesitant expectant mothers with a 95% exact, Binomial confidence interval with a half-width ≤0.03. Based on previous research, we assumed 10% of

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participants would be vaccine-hesitant and calculated a sample size of 600 participants would be needed to provide ≥80% power to detect a 0.2 unit difference in proportions between hesitant and non-hesitant groups using Fisher’s exact test and alpha equal to 0.05.18

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Results

Of 1435 expectant parents screened, 648 were enrolled for a 45% response rate. Of these,

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610 were expectant mothers and 38 were co-parents (all fathers). Among the expectant mothers not enrolled, we missed 660 (46%) due to short waiting room times, 114 (8%) declined to participate, and 13 (1%) did not meet inclusion criteria. Following enrollment, we excluded 10 expectant fathers from analysis due to the inability to link them to an expectant mother (Figure 2).

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The majority of expectant mothers were non-Hispanic White, 30 years of age or older, and married (Table 1). About half of the mothers were expecting their first baby, and the majority did not consider their pregnancy to be high risk. Overall, 50 of 610 expectant mothers

expectant mothers was 13 (p25=4, p75=30) with 31% scoring ≤5.

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(8%, 95% CI: 6.1%, 10.7%) were vaccine hesitant (Figure 3). The median PACV score among

There was no significant difference in the proportion of first-born, age group, marital

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status, household income, number of children in household, race or high risk pregnancies

between hesitant and non-hesitant expectant mothers (P>0.10, Table 1). Receipt of an annual

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influenza vaccine was more common among non-hesitant expectant mothers compared with those who were hesitant (79% vs. 32%, P