Background: Parental vaccine hesitancy could lead to outbreaks of vaccine-preventable diseases. Although parental vaccine hesitancy exists in the Vietnamese community, no research has directly investigated this social phenomenon in Vietnam. Among the validated measures, the 15-item Parent Attitudes About Childhood Vaccines survey tool (PACV) was reliable for predicting vaccine-hesitant parents. However, the PACV was not available in Vietnamese. This study aimed to develop a Vietnamese version of the PACV and examine factors associated with parental vaccine hesitancy in Hue city, Vietnam. Methods: This study was a cross-sectional study. The English PACV was translated into Vietnamese with content and face validation. Self-administered questionnaires were distributed to 400 parents at ten commune health centres in Hue city, Vietnam. The parents were asked to answer the questionnaire again after two weeks for the test–retest reliability. The Vietnamese PACV reliability was assessed using Cronbach's alpha and McDonald's omega, and the intra-class correlation (ICC) coefficients were used for the test–retest reliability. The construct validity was tested by the hypothesis that parental vaccine hesitancy would be related to the intention of getting the children vaccinated. Exploratory factor analysis was also undertaken to determine the construct validity. Bivariate and multivariable logistic regression were used to identify the factors associated with parental vaccine hesitancy. Results: The Vietnamese PACV final version (PACV-Viet) contained 14 items. Three hundred and fifteen parents returned completed questionnaires, giving a response rate of 78.8%. The Cronbach's alpha and McDonald's omega were 0.72 and 0.70, respectively. Out of 315 parents, 84 responses were returned for test–retest reliability. All ICCs were good to excellent, ranging from 0.81 to 0.99. The PACV-Viet was confirmed to have construct validity. Using the PACV-Viet, 8.9% of the parents were found hesitant to childhood vaccination. Being unemployed and having seen the news about adverse events following immunisation were associated with parental vaccine hesitancy, with AOR = 3.2 (95% CI 1.3–8.0) and AOR = 4.5 (95% CI 1.2–16.7), respectively. Conclusions: The PACV-Viet is a valid and reliable tool. Community outreach is necessary to alleviate parents' concerns about childhood vaccination.
Keywords: Vaccination hesitancy; Vaccines; Parents; Child; Immunisation programs; Vietnam
Vaccines have significantly contributed to global health by reducing the burden of numerous infectious diseases [[
Parental vaccine hesitancy is not a novel phenomenon [[
Among the validated tools for parental vaccine hesitancy measure, the Parent Attitudes about Childhood Vaccines (PACV) is one of the most frequently used [[
Therefore, it is important to adapt the PACV, conduct its validation study in the Vietnamese language, and subsequently identify factors associated with parental vaccine hesitancy in Vietnam. This study was conducted to (i) develop a Vietnamese version of the PACV and (ii) examine factors associated with parental vaccine hesitancy in Hue city, Vietnam.
This was a cross-sectional study. In 2021, Hue city had 27 wards, each with a commune health centre. These are the primary points of vaccine delivery in the Vietnamese Expanded Programs on Immunisation (EPI) [[
The study collected data from parents. Inclusion criteria included (i) mothers and fathers aged 18 and above, (ii) having at least a child aged less than five years old. Parents were excluded from the study if they did not wish to participate or had been living in Hue city for less than three months.
The English PACV was translated into Vietnamese language using the back translation method [[
The sample size was estimated using the formula for detecting a difference between two proportions [[
Graph
Due to the lack of data on vaccine hesitancy in Vietnam, the calculation used published data from another South-East Asian country. According to a study in Malaysia using the PACV, 20.4% of vaccine-hesitant parents were under 30, while 8.4% were aged 30 or older [[
The parents were recruited at commune health centres from September 10 to October 15, 2021. Each centre usually had one or two EPI sessions per month. The parents were recruited during or after their child's EPI session. A child's mother and father could both participate in the study. The recruited parents might not necessarily be a couple. Either or both parents received the information sheet and signed the informed consent form. In Vietnamese society, mothers' roles were traditionally responsible for the children's health [[
The data were collected using a paper-based questionnaire, which the parents completed at the commune health centres. The questionnaire included the Vietnamese PACV and other questions such as parents' gender, parental educational level and employment status, number of children [[
The PACV was a self-administered tool. It contains 15 items divided into three-factor domains: 'Behaviour' (items Q1 and Q2), 'Safety and efficacy' (items Q7–Q10) and 'General attitude and trust' (items Q3–Q6 and Q11–Q15) [[
The study used IBM's SPSS version 26 for data management and Stata software (Stata/SE 16.1, College Station, Texas) for statistical analyses. Items Q1 and Q2 were not included in the reliability and construct validity analysis because they are dichotomous, unlike other Likert questions of the PACV [[
The Vietnamese PACV reliability was evaluated using Cronbach's alpha and McDonald's omega. Cronbach's alpha and McDonald's omega of 0.7 are acceptable for internal consistency [[
To determine the construct validity, the study assessed its convergent aspect [[
Bivariate and multivariable logistic regression were used to examine the factors associated with parental vaccine hesitancy. Variance inflation factor (VIF) was used for the multicollinearity test. VIF greater than 5 is a sign of detecting multicollinearity [[
The expert panel agreed that the translation was appropriate for the Vietnamese population and the given purpose, but suggested minor improvements for precision. Item Q3 ('How sure are you that following the recommended shot schedule is a good idea for your child?') measured the scope to which the parent believes that having a vaccination is a good idea. This question response was based on a 0–10 scale. However, the Vietnamese meaning ('How sure are you that ...') referred to a yes/no question and could confuse the respondent. An appropriate version of item Q3 was recommended by adding 'To what extent ...' to the Vietnamese question. Item Q4 ('Children get more shots than are good for them') was noted to be difficult to interpret. Although one expert considered item Q4 was not grammatically correct when translated to Vietnamese, the panel decided to keep the literalness of the question. In addition, items Q14 ('I am able to openly discuss my concerns about shots with my child's doctor') and Q15 ('All things considered, how much do you trust your child's doctor?') also needed to be slightly modified by changing 'child's doctor' to 'vaccination consulting doctor', because children often do not have their own doctor in Vietnam.
Following the content validation by the expert panel, the pre-final Vietnamese PACV was produced and ready for face validity testing. Among 30 parents who participated in the pre-test, feedback was collected with no significant complaint, and no question was considered difficult to understand. Almost all the parents found the questionnaire easy to complete. The Vietnamese PACV was then used in the primary survey.
Forty questionnaires were distributed to the parents in each of the ten commune health centres. In a total of 400 questionnaires, 315 were fully filled with information and returned, giving an estimated response rate of 78.8%. The parents' socio-demographic characteristics are outlined in Table 1. The majority of the parents were mothers (71.8%), and the mean age was 30.8 (SD 5.9) years. Around 68.3% of the parents were employed, and about two-thirds had seen information about adverse events following immunisation (70.8%).
Table 1 Socio-demographic characteristics of the participants
Characteristics % Parent Mother 226 71.8 Father 89 28.3 Age 18—29 years 132 41.9 ≥30 years 183 58.1 Number of children 1 96 30.5 2 163 51.8 3 and above 56 17.8 Ethnicity Kinh 313 99.4 Other 2 0.6 Religion None 160 50.8 Buddhism 139 44.1 Catholic 16 5.1 Marital status Married 312 99.1 Single 3 0.9 Education level Secondary school and below 82 26.0 High/Vocational/Technical school 91 28.9 College/University degree and above 142 45.1 Employment status Employed 215 68.3 Unemployed 100 31.8 Monthly household income in Vietnamese Dong (1 United States Dollar = 22,820 Vietnamese Dong as of December 2021) < 6,000,000 66 21.0 6,000,000—< 8,000,000 66 21.0 8,000,000—< 10,000,000 55 17.5 10,000,000 + 128 40.6 Preference on type of vaccine Free 268 85.1 Paid 47 14.9 Source of information on childhood vaccination No information/No source 7 2.2 Family 88 27.9 Friends and acquaintances 33 10.5 Healthcare professional 173 54.9 Public health authorities 212 67.3 Television 60 19.1 Print media 15 4.8 Internet searches 78 24.8 Social media networks 49 15.6 Have seen news about adverse events following immunisation Yes 223 70.8 No 92 29.2 Will take the COVID-19 vaccine Yes 268 85.1 No/Not sure 47 14.9 Will let the children take the COVID-19 vaccine (when possible) Yes 236 74.9 No/Not sure 79 25.1
Abbreviations: N number of parents, COVID-19 Coronavirus Disease 2019
Table 2 provides descriptive statistics for the parent's response to the Vietnamese PACV. Approximately one-third (31.4%) of the 315 parents admitted to postponing their child's shot for reasons other than illness or allergy, and 13.7% of them had decided not to vaccinate their child. Notably, parents were greatly concerned about the vaccines' side effects (79.1%). According to the response, some parents also considered themselves hesitant about childhood vaccination (15.9%). However, most parents agreed they could trust the information they received about the shots (93.3%) and the vaccination consulting doctor (87.3%).
Table 2 PACV-Viet statements and the parent's response
Item Response Count (%) Q1 Have you ever delayed having your child get a shot for reasons other than illness or allergy? 99 (31.4) No 210 (66.7) Don't know 6 (1.9) Q2 Have you ever decided not to have your child get a shot for reasons other than illness or allergy? 43 (13.7) No 259 (82.2) Don't know 13 (4.1) Q3 How sure are you that following the recommended shot schedule is a good idea for your child? 18 (5.7) 6–7 19 (6.0) 8–10 278 (88.3) Q4 Children get more shots than are good for them 276 (87.6) Not sure 30 (9.5) Disagree 9 (2.9) Q5 I believe that many of the illnesses that shots prevent are severe 9 (2.9) Not sure 32 (10.2) Agree 274 (87.0) Q6 It is better for my child to develop immunity by getting sick than to get a shot 31 (9.8) Not sure 48 (15.2) Disagree 236 (74.9) Q7 It is better for children to get fewer vaccines at the same time 101 (32.1) Not sure 116 (36.8) Disagree 98 (31.1) Q8 How concerned are you that your child might have a serious side effect from a shot? 249 (79.1) Not sure 18 (5.7) Not concerned 48 (15.2) Q9 How concerned are you that any one of the childhood shots might not be safe? 220 (69.8) Not sure 30 (9.5) Not concerned 65 (20.6) Q10 How concerned are you that a shot might not prevent the disease? 183 (58.1) Not sure 58 (18.4) Not concerned 74 (23.5) Q11 If you had another infant today, would you want him/her to get all the recommended shots? 2 (0.6) I don't know 11 (3.5) Yes 302 (95.9) Q12 Overall, how hesitant about childhood shots would you consider yourself to be? 50 (15.9) Not sure 38 (12.1) Not hesitant 227 (72.1) Q13 I trust the information I receive about shots 2 (0.6) Not sure 19 (6.0) Agree 294 (93.3) Q14 I am able to openly discuss my concerns about shots with my child's doctor 4 (1.3) Not sure 16 (5.1) Agree 295 (93.7) Q15 All things considered, how much do you trust your child's doctor? 15 (4.8) 6–7 25 (7.9) 8–10 275 (87.3)
Italic answers indicate hesitancy Abbreviation: PACV-Viet The Vietnamese version of the Parent Attitudes About Childhood Vaccines survey tool
Table 3 shows the mean, SD, corrected item-total correlation for each item, alpha value if the item was deleted and the factor loadings on the PCA. The corrected item-total correlation was negative for item Q4. Removing item Q4 could increase the alpha. Moreover, item Q4 also had a negative factor loading. Therefore, item Q4 was deleted and omitted from further analysis. As a result, the Vietnamese version of the PACV (PACV-Viet) contains 14 items.
Table 3 The PACV-Viet items with Cronbach's alpha if item deleted and PCA factor loadings
Items Mean SD Corrected item-total correlation Alpha (If Item Deleted) Loadings Q3 How sure are you that following the recommended shot schedule is a good idea for your child? 9.1 1.5 0.5 0.59 0.4 Q4 Children get more shots than are good for them 1.7 0.8 -0.4 0.72 -0.3 Q5 I believe that many of the illnesses that shots prevent are severe 1.8 0.7 0.2 0.64 0.3 Q6 It is better for my child to develop immunity by getting sick than to get a shot 3.8 0.9 0.2 0.63 0.2 Q7 It is better for children to get fewer vaccines at the same time 3.0 1.0 0.2 0.64 0.1 Q8 How concerned are you that your child might have a serious side effect from a shot? 3.9 1.1 0.3 0.62 0.2 Q9 How concerned are you that any one of the childhood shots might not be safe? 3.8 1.2 0.4 0.61 0.2 Q10 How concerned are you that a shot might not prevent the disease? 3.6 1.2 0.2 0.63 0.2 Q11 If you had another infant today, would you want him/her to get all the recommended shots? 1.1 0.2 0.2 0.63 0.2 Q12 Overall, how hesitant about childhood shots would you consider yourself to be? 2.0 1.1 0.5 0.59 0.3 Q13 I trust the information I receive about shots 1.7 0.6 0.5 0.58 0.4 Q14 I am able to openly discuss my concerns about shots with my child's doctor 1.7 0.7 0.4 0.60 0.3 Q15 All things considered, how much do you trust your child's doctor? 9.0 1.4 0.5 0.58 0.4
Abbreviations: PACV-Viet The Vietnamese version of the Parent Attitudes About Childhood Vaccines survey tool, PCA Principal component analysis, SD Standard deviation
The overall Cronbach's alpha and McDonald's omega for the PACV-Viet were 0.72 and 0.70, respectively. Out of 315 parents, 84 questionnaires were returned from the retest after two-week intervals. As shown in Table 4, the ICC was good to excellent for each item, ranging from 0.81 to 0.99.
Table 4 Test–retest reliability of the PACV-Viet after two weeks
Items ICC 95% CI Q3 How sure are you that following the recommended shot schedule is a good idea for your child? 0.98 0.97—0.99 Q5 I believe that many of the illnesses that shots prevent are severe 0.85 0.77—0.90 Q6 It is better for my child to develop immunity by getting sick than to get a shot 0.89 0.84—0.93 Q7 It is better for children to get fewer vaccines at the same time 0.96 0.94—0.98 Q8 How concerned are you that your child might have a serious side effect from a shot? 0.81 0.71—0.88 Q9 How concerned are you that any one of the childhood shots might not be safe? 0.91 0.87—0.94 Q10 How concerned are you that a shot might not prevent the disease? 0.90 0.85—0.94 Q11 If you had another infant today, would you want him/her to get all the recommended shots? 0.89 0.82—0.93 Q12 Overall, how hesitant about childhood shots would you consider yourself to be? 0.91 0.85—0.94 Q13 I trust the information I receive about shots 0.86 0.79—0.91 Q14 I am able to openly discuss my concerns about shots with my child's doctor 0.83 0.74—0.89 Q15 All things considered, how much do you trust your child's doctor? 0.99 0.98—0.99
Number of test–retest questionnaires evaluated was 84 Abbreviations: PACV-Viet The Vietnamese version of the Parent Attitudes About Childhood Vaccines survey tool, ICC Intra-class correlation coefficient, CI Confidence interval
From the PACV-Viet, 28 (8.9%) parents were classified as vaccine-hesitant (score ≥ 50). As for the intention of getting the children vaccinated, 14.9% of the parents were not sure that they would keep their children fully vaccinated and on schedule in the future. Following the frequencies cross-tabulated in Table 5, a Fisher's exact test was performed to determine the association between future vaccination intention with parental vaccine hesitancy. There was a significant association between the future vaccine intention and parental vaccine hesitancy (two-tailed p-value < 0.001).
Table 5 The association between hesitant parents and future vaccination intention
Hesitant parents Future vaccination intention Total Fully vaccinated and on schedule (%) Not sure (%) No 261 (90.9) 26 (9.1) 287 Yes 7 (25.0) 21 (75.0) 28 Total 268 (85.1) 47 (14.9) 315 Fisher's Exact Test
The PACV-Viet were appropriate to proceed with factor analysis following the KMO value and Bartlett's test of sphericity results. Using Promax rotation, the EFA identified four factors with Eigenvalues above 1, accounting for 63.6% of the total variance. On the scree plot, the curve's elbow occurred at three (Fig. 1). Repeated testing with three-factor and four-factor models, three factors were the most conceptually suitable.
Graph: Fig. 1Scree plot of eigenvalues of factors in the PACV-Viet
Table 6 shows the factor loading of items and three factors extracted from the EFA. Items Q3, Q5 and Q12-Q15 formed Factor 1, reflecting the 'General attitudes' domain from the original PACV. Items Q8-Q10 correlated to form Factor 2, the 'Safety and efficacy' domain from the original PACV. The remaining items Q6, Q7 and Q11 formed a new Factor 3, namely 'Children and vaccination'.
Table 6 Items, factor loadings and factors of the PACV-Viet
Factor 1 Factor 2 Factor 3 General attitudes Safety and efficacy Children and vaccination Q3 How sure are you that following the recommended shot schedule is a good idea for your child? 0.6 Q5 I believe that many of the illnesses that shots prevent are severe 0.6 Q12 Overall, how hesitant about childhood shots would you consider yourself to be? 0.4 Q13 I trust the information I receive about shots 0.8 Q14 I am able to openly discuss my concerns about shots with my child's doctor 0.8 Q15 All things considered, how much do you trust your child's doctor? 0.6 Q8 How concerned are you that your child might have a serious side effect from a shot? 0.8 Q9 How concerned are you that any one of the childhood shots might not be safe? 0.9 Q10 How concerned are you that a shot might not prevent the disease? 0.9 Q6 It is better for my child to develop immunity by getting sick than to get a shot 0.5 Q7 It is better for children to get fewer vaccines at the same time 0.7 Q11 If you had another infant today, would you want him/her to get all the recommended shots? 0.5
Abbreviation: PACV-Viet The Vietnamese version of the Parent Attitudes About Childhood Vaccines survey tool
Table 7 displays factors associated with parental vaccine hesitancy. The bivariate logistic regression model showed that being unemployed (OR = 2.7, 95% CI 1.3–6.0) and having seen the news about adverse events following immunisation (OR = 3.8, 95% CI 1.1–12.7) were associated with parental vaccine hesitancy. The results confirmed the significantly associated variables in the multivariable logistic regression model. The Hosmer–Lemeshow test indicated a good logistic regression model fit (P-value = 0.3), and the area under the curve was 0.78. The multicollinearity test resulted in a mean VIF of 1.59, indicating no serious multicollinearity problems in this model. When adjusted for all other variables, factors associated with parental vaccine hesitancy were being unemployed (AOR = 3.2, 95% CI 1.3–8.0) and having seen the news about adverse events following immunisation (AOR = 4.5, 95% CI 1.2–16.7).
Table 7 Factors associated with parental vaccine hesitancy
Unadjusted Adjusted Variables OR (95% CI) OR (95% CI) Age (years) 18—29 years 132 1 1 from 30 years 183 1.3 (0.6—3.0) 0.488 0.7 (0.2—2.0) 0.493 Parent Father 89 1 1 Mother 226 1.9 (0.7—5.2) 0.207 1.5 (0.5—4.4) 0.464 Number of children 1 96 1 1 2 163 1.3 (0.5—3.3) 0.595 1.5 (0.5—4.6) 0.483 3 and above 56 1.5 (0.5—4.8) 0.469 2.3 (0.6—9.3) 0.24 Religion None 160 1 1 Buddhism 139 1.3 (0.6—2.8) 0.559 1.6 (0.7—4.0) 0.303 Catholic 16 0.8 (0.1—6.2) 0.792 0.8 (0.1—7.6) 0.879 Education level Secondary school and below 82 1 1 High/Vocational/Technical school 91 2.4 (0.7—8.0) 0.151 3.2 (0.9—11.8) 0.086 College/University degree and above 142 1.6 (0.7—6.7) 0.195 2.5 (0.62 -9.8) 0.203 Employment status Employed 215 1 1 Unemployed 100 2.7 (1.3—6.0) 0.012 3.2 (1.3—8.0) 0.014 Monthly household income in Vietnamese Dong (1 United States Dollar = 22,820 Vietnamese Dong as of December 2021) < 6,000,000 66 1 1 6,000,000—< 8,000,000 66 0.4 (0.2—1.4) 0.129 0.3 (0.1—1.4) 0.121 8,000,000—< 10,000,000 55 1.4 (0.5—4.0) 0.505 1.5 (0.4—4.9) 0.542 10,000,000 + 128 0.5 (0.2—1.4) 0.166 0.5 (0.1—1.5) 0.2 Preference on type of vaccine Free 268 1 1 Paid 47 2.1 (0.8—5.2) 0.123 3.0 (0.9—9.5) 0.067 Have seen news about adverse events following immunisation No 92 1 1 Yes 223 3.8 (1.1—12.7) 0.034 4.5 (1.2—16.7) 0.027 Will take the COVID-19 vaccine Yes 268 1 1 No or not sure 47 0.7 (0.2—2.3) 0.515 0.5 (0.1—2.0) 0.314 Will let the children take the COVID-19 vaccine (when possible) Yes 236 1 1 No or not sure 79 1.8 (0.8—4.0) 0.178 2.2 (0.8—5.9) 0.112
Abbreviations: OR Odds ratio, CI Confidence interval, COVID-19 Coronavirus Disease 2019
The study has two major findings. First, the most important finding was the development of a reliable and valid Vietnamese version of the PACV. To the best of the authors' knowledge, the PACV-Viet is the first validated survey tool in Vietnamese for parental vaccine hesitancy. Second, the factors associated with parental vaccine hesitancy were being unemployed and having seen news about adverse events following immunisation.
During analysis, item Q4 was removed from the PACV-Viet, and this question also confused the translators and reviewers during the translation. This was likely because there was no precise translation from English to Vietnamese for 'get more shots than are good' without changing the author's expression. Since this study maintained the denotation of the question when making the PACV-Viet, most of the parents answered this item without getting the latent meaning. The problem was also noted in the development of the PACV and other validation studies [[
In this study, items Q1 and Q2 were excluded from the psychometric properties testing. Dichotomous items require different reliability and validity assessment methods [[
The PACV-Viet had acceptable overall Cronbach's alpha and McDonald's omega, which were 0.72 and 0.70, respectively. With good to excellent values of the ICC, the PACV-Viet is stable and reliable over time. The PACV-Viet was also confirmed to have convergent validity through hypothesis testing. Similar to the finding, the PACV's outcomes were associated with future child immunisation status or odds of the non-timeliness of the first dose of measles [[
In the PACV-Viet, the EFA yielded a three-factor model. However, there were differences in the factor-loading structure of items Q6, Q7 and Q11. These questions both mentioned how the parents were concerned about getting their children vaccinated. Thus, they formed a new domain labelled 'Children and vaccination'. The Malay version also bore a different factor structure [[
Using the PACV-Viet, 8.9% of the parents were vaccine-hesitant in Hue city, Vietnam. This finding is comparable with recent similar studies using the PACV, such as results from Peru (9.8%), Iraq (9.9%), Saudi Arabia (11%), Malaysia (11.6%) and the United Arab Emirates (12%). The finding is lower in this study than those in other studies, including Ireland (15%), Canada (15%), Indonesia (15.9%), Italy (34.7%) and some in the United States (> 20%). These differences are likely due to the characteristics of the studied populations and settings. With a hesitancy rate of 8.9%, however, one-third of the parents reported they had delayed their children's vaccination. According to a study about the timeliness of vaccination, only 33% of the parents had their children vaccinated on schedule in Hue city, Vietnam [[
Being unemployed was significantly associated with parental vaccine hesitancy. Compared with other studies in the South-East Asia region, the result was consistent with the Malaysian study [[
Parents were more likely to be vaccine-hesitant if they had seen the news about adverse events following immunisation. In a study in northern Vietnam, many urban participants would refuse vaccination after hearing news about adverse events following immunisation in the media [[
The study has some limitations. First, the representativeness of data could be limited since the recruitment was done at commune health centres. The study also did not account for commonalities among parents within selected centres. Thus, the clustering effect could not be investigated. Second, self-administered questionnaires might raise the social-desirability bias as the participants might not well remember the information and answer questions to their advantage. Moreover, parental vaccine hesitancy might be a sensitive topic to some parents, which could not accurately reflect the actual condition. The parents might already consider themselves vaccine-hesitant and refuse to give accurate answers. Third, the study used a categorical variable (i.e. the intention of getting the children vaccinated) instead of a continuous variable (i.e. another scale) in the construct validity analysis. A categorical variable is less informative and can be more difficult to compare to other scales of the same construct. Besides, correlational methods are commonly used to assess convergent validity, which is more accurate when the variables are continuous [[
In conclusion, this study developed the PACV-Viet using several validation processes. Notably, the 14-item PACV-Viet was found reliable and valid. The tool can be used to report parental vaccine hesitancy among the Vietnamese population. It is valuable to identify parental vaccine hesitancy in Hue City, Vietnam. The findings could contribute significantly to local and regional knowledge on this important topic. Community-based outreach can be instrumental in addressing vaccine concerns and enabling parents to continue their child's vaccination.
The authors express their sincere thanks to the health centres and all parents participating in the study. We are also grateful to the translators, the expert board, and anyone from Hue University of Medicine and Pharmacy who assisted with this study.
BQQT, KICO and MJ conceptualised and designed the study. AS and JK commented on methods. BQQT collected the data. BQQT and KICO analysed and interpreted the data. BQQT wrote the first draft of the manuscript. KICO, AS, JK and MJ revised the manuscript. All authors read and approved the final manuscript.
Not applicable.
The data are not publicly available due to them containing information that could compromise research participants' consent. Data and materials (i.e. the PACV-Viet) are however available from the authors upon reasonable request. Please contact Dr. Bao Quy Quoc Truong (tqqbao@huemed-univ.edu.vn) for any requests.
The study obtained permission for translation and use from the PACV's author. The ethical approvals were obtained from the Research Ethics Committee, the Graduate School of Medicine, the University of Tokyo, Japan (No. 2021109NI) and the Ethics Committee of Hue University of Medicine and Pharmacy, Hue University, Vietnam (No. H2021/413). Written informed consents were obtained from all parents. The survey was also done anonymously, with all personal information coded to conceal identity and stored securely. The study was carried out in accordance with the relevant regulations and guidance.
Not applicable.
The authors declare no competing interests.
- COVID-19
- Coronavirus Disease 2019
• PACV
- The Parent Attitudes About Childhood Vaccines survey tool
• EPI
- Expanded Programs on Immunisation
• ICC
- Intra-class Correlation Coefficient
• PCA
- Principal Component Analysis
• EFA
- Exploratory Factor Analysis
• KMO
- Kaiser-Meyer Olkin
• VIF
- Variance Inflation Factor
- PACV-Viet
- The Vietnamese version of the Parent Attitudes About Childhood Vaccines survey tool
• OR
- Odds Ratio
• CI
- Confidence interval
• AOR
- Adjusted Odds Ratio
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By Bao Quy Quoc Truong; Ken Ing Cherng Ong; Akira Shibanuma; Junko Kiriya and Masamine Jimba
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