Vaccine Hesitancy Regarding Childhood Vaccinations Among Parents

Immunization services are essential primary healthcare practices implemented to protect infants, children, and adults from infectious diseases by vaccinating them before the period in which their risk of infection is highest (1). Immunization efforts have prevented 154 million deaths worldwide over the past 50 years. Among those whose lives were saved through immunization, 101 million were infants, and vaccines represent the most important health service for infant health (2). In Türkiye, the primary objective of the Expanded Program on Immunization is to ensure that every newborn is immunized in accordance with the national vaccination schedule against pertussis, diphtheria, tetanus, measles, rubella, mumps, tuberculosis, poliomyelitis, hepatitis B, haemophilus influenzae type B, pneumococcus, hepatitis A, and varicella (1).

The World Health Organization (WHO) defines vaccine hesitancy as “a delay in acceptance or refusal of safe vaccines despite the availability of vaccination services.” Vaccine hesitancy is a complex concept and varies depending on time, location, and vaccine type (3). It is an increasingly important public health problem; indeed, in 2019, the WHO listed vaccine hesitancy among the ten global threats to health (4). In Türkiye as well, vaccine hesitancy appears to be rising as a public health concern (5). While the global rate of vaccine hesitancy has been estimated to be 21.1%, this rate has been calculated as being 13% in Türkiye (6).

Antalya, the fifth-largest city in Türkiye, is home to approximately 500,000 children aged 13 years and under. The aim of this study was to identify the reasons for vaccine hesitancy among parents in Antalya and to shed light on possible interventions in order to address this issue.

This cross-sectional study included all parents in Antalya in 2023 who refused at least one vaccine dose. In 2023, a total of 971 parents refused at least one childhood vaccine. The sample size was calculated using G*Power; assuming a medium effect size, an alpha error of 0.05, and a statistical power of 0.90, the minimum required sample size was determined to be 143. From among the 971 parents who refused at least one vaccine dose, 216 parents were randomly selected to account for the possibility of refusal to participate.

These parents were contacted using the phone numbers recorded in the national health information systems. It was not known beforehand whether the phone number belonged to the mother or the father. The first number was called initially, and if necessary, the second number was attempted. The parent reached by phone was first informed about the study, and if they agreed to participate, the questions in the structured questionnaire developed by the researchers were administered.

Ethical approval for this study was obtained from the Clinical Research Ethics Committee of Antalya Training and Research Hospital (approval number: 19/13, date: 05.12.2024).

Statistical Analysis

Data were analyzed using IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp., Armonk, NY, USA). Descriptive findings are presented as numbers, percentages, means, and medians. The chi-square test was used for group comparisons, and p<0.05 was considered statistically significant. In addition, open-ended questions about the reasons for vaccine hesitancy were asked, and the responses were coded and grouped thematically. The thematic grouping was first conducted independently by the researchers and then finalized together.

A total of 216 parents were initially included in this study. This study was completed with 172 parents. Among the 44 parents who did not participate, 23 (52.3%) could not be reached, 10 (22.7%) refused participation, 7 (15.9%) had initially refused vaccination but were later found to have completed the vaccinations, 2 (4.5%) had language barriers, and 2 (4.5%) had other reasons for non-participation.

Among the children included in this study, 72 (41.9%) were girls and 100 (58.1%) were boys. A total of 169 children (98.3%) were citizens of the Republic of Türkiye, while 2 (1.2%) were citizens of Russia and 1 (0.6%) was a citizen of Germany. The parent interviewed was the mother in 69.8% of cases. In total, 59.9% of the parents had completed a university degree or higher. More than half of the parents had one or two children. The median age of the children was 39.5 months, while the median age of the parents was 35 years (Table I).

Among the vaccines, the most frequently administered was the 3^rd dose of the conjugated pneumococcal vaccine, followed by the 1^st dose of the hepatitis B vaccine. The least frequently administered vaccine was the 2^nd dose of the oral polio vaccine, followed by the 1^st dose of the hepatitis A vaccine (Table II).

In addition, the number of children who received only the hepatitis B vaccine at birth (1^st dose of hepatitis B) was 33 (19.2%), while the number of children who had received no vaccination at all was 46 (26.7%).

Table III presents the distribution of responses given to the questions regarding the reasons for vaccine refusal.

Among the responses to the question “Are there any vaccines you particularly do not trust, and if so, which ones?”, the most common answer was “all vaccines”; the second most frequent was “combined vaccines”, and the third was “COVID-19 vaccines” (Table IV).

The responses of parents who answered “Yes” to the question “Did your concerns about vaccines arise after listening to a particular person/share or after an event?” were categorized into thematic groups. The most frequently recurring theme was “incidents interpreted as adverse events following vaccination by parents” (Table V).

When the parents’ answers to the question “Can your concerns about vaccines change positively?” were compared, it was found that mothers, when compared to fathers, statistically significantly more often answered “No” (p=0.015). When divided into two age groups, parents aged 34 and under were statistically significantly more likely to answer “No” when compared to older parents (p=0.044). Those parents whose child had received zero vaccines (i.e., refused all vaccines) were also statistically significantly more likely to answer “No” when compared to the others (p=0.005), while parental education levels did not create a significant difference (p=0.382) (Table VI).

According to the findings of this research, the majority of participants did not consider vaccines to be safe, and a significant proportion stated that vaccines were harmful to their child’s health. It was also determined that social media and the coronavirus disease-2019 (COVID-19) period increased parents’ hesitations about vaccines. Incidents perceived as vaccine side effects were found to be the most common theme associated with vaccine hesitancy. It was further identified that the attitudes of female participants and younger participants regarding vaccine hesitancy were more resistant to change when compared to others.

The results of this study show that a considerable proportion of parents did not trust vaccines and believed that vaccines are harmful to their children’s health. This finding is consistent with both previous studies conducted in Türkiye and international studies (5, 7, 8). A global systematic review and meta-analysis reported that distrust in vaccines and the belief that vaccine contents are harmful are among the most common reasons for vaccine hesitancy worldwide (9).

Through thematic analysis of the responses to the open-ended questions, the most frequently stated theme was “incidents interpreted as adverse events following vaccination by the participant.” It is known that true adverse events following vaccination, as well as the misinterpretation of unrelated health conditions as vaccine side effects, contribute to vaccine hesitancy (10-12). However, this study demonstrated that parents had low levels of knowledge about vaccine side effects and considered certain health conditions, notably conditions which could not be caused by vaccines, as vaccine-related adverse effects. For example, one participant perceived their child’s cystic fibrosis diagnosis as a vaccine side effect. Although the absence of any relationship between autism and vaccines has been consistently demonstrated (13, 14), in this study, some parents still attributed their child’s autism diagnosis to vaccines. Another study conducted in Türkiye similarly showed that parents interpreted health conditions not caused by vaccines as vaccine side effects (15). These findings highlight the importance of better informing parents about vaccine side effects. Preventing health conditions unrelated to vaccination from being perceived as side effects may reduce the proportion of parents who distrust vaccines or believe vaccine contents are harmful. In another study conducted in Türkiye, when healthcare workers were asked to propose solutions to vaccine hesitancy, the most common suggestion was “informing the public that most vaccine side effects are minor” (16).

In this study, parents were asked whether there were specific vaccines they particularly did not trust. The majority of participants stated that there was no specific vaccine they distrusted more than others. However, among those who did name particular vaccines, the most frequent responses were combined vaccines and COVID-19 vaccines. A study conducted in the United States similarly found that although most parents did not identify a specific vaccine they distrusted, combined vaccines were commonly believed to cause more side effects (8). Another study indicated that the belief that combined vaccines are harmful represents an increasing risk factor for vaccine hesitancy (17). Combined vaccines involve administering two or more vaccines in the same session. Combined vaccines enable timely immunization during the most vulnerable period of infancy and minimize the number of clinic visits needed. Thus, combined vaccines save time and cost and provide a less traumatic vaccination experience for the child. Moreover, combined vaccines have been shown to be as safe as single-dose vaccines (18). During parental education efforts, the safety of combined vaccines should be emphasized and misconceptions should be clarified.

Another prominent finding of this study was that the COVID-19 period and COVID-19 vaccines increased vaccine hesitancy. A total of 87.8% of participants stated that the COVID-19 period negatively affected their trust in vaccines. Similar findings have been reported in both national and international studies (19, 20). The COVID-19 pandemic negatively affected public health practices both directly and indirectly. The unexpected and rapidly evolving nature of the pandemic, along with the infodemic which followed, negatively influenced many public health interventions, including immunization efforts. Therefore, correcting the misinformation which emerged during the COVID-19 period should be a priority for public education on immunization.

In today’s digital age, the ways in which individuals access health information have also changed. While social media facilitates the flow of information, it also accelerates the spread of misinformation. In this study, a significant proportion of parents stated that social media negatively influenced their views on vaccines. The role of social media in increasing vaccine hesitancy has been repeatedly demonstrated (5, 7, 21). Although social media contributes to the spread of false or misleading information, its wide reach also offers an opportunity to enhance public knowledge and awareness of public health issues (22). Interestingly, parents themselves also suggested that social media should be used as a tool to counter vaccine hesitancy (19, 23).

The process of vaccine hesitancy, and the thoughts, attitudes, and behaviors of parents within this process, cannot be easily defined by strict boundaries. Individuals fall along a broad continuum between fully accepting all vaccines and completely rejecting them (24). It is important to provide accurate and clear information to individuals within this “gray zone.” In this study, one-third of participants answered “Yes” or “Unsure” to the question “Can your concerns about vaccines change positively?”. Male participants, when compared to female participants, and participants aged 35 and above, when compared to younger participants, were more open to positive change. The literature shows that vaccine hesitancy is more common among mothers and younger parents (8, 25-27). The underlying reasons why mothers and younger parents exhibit more hesitancy and less openness to change should be further explored. The fathers’ views regarding vaccine hesitancy were found to be more open to positive change. Including fathers in decisions related to child health and expanding “maternal and child health” to “parental and child health” may support efforts to improve public health outcomes.

Study Limitations

This study had several strengths. The sample size was relatively large and included both mothers and fathers, allowing for a broader understanding of parental perspectives on vaccine hesitancy. The random selection of the participants from all of those parents who refused at least one childhood vaccine in 2023 strengthened the representativeness of the findings. There were also limitations. As the data were collected through phone interviews, the number of questions had to be kept to a limit, which reduced the depth of information. In addition, the thematic analysis used in this study did not constitute a full qualitative research design but was instead applied in order to organize and group open-ended responses. Although the sample was large and randomly selected, its representativeness was limited to one province and did not reflect the entire country; therefore, larger and multi-center studies are needed in order to achieve national representativeness.

This study was conducted with 172 mothers and fathers who had refused at least one childhood vaccine. The majority of the participants stated that they did not trust vaccine contents and that vaccine side effects were the main reason for their hesitancy. Combined vaccines and COVID-19 vaccines were specifically mentioned as the vaccines they distrusted. The COVID-19 period and social media emerged as factors which increased vaccine hesitancy. Fathers, when compared with mothers, were found to be more open to positive changes regarding vaccine hesitancy.

Providing accurate information to the public about vaccine side effects, and addressing the misinformation and misconceptions which arose during the COVID-19 period are essential steps. The influence of social media can be reversed through proper use. Increasing the fathers’ involvement in the decision-making process for child immunization may also help reduce vaccine hesitancy.