Hepatitis B (HepB) is an infection of the liver caused by the HepB virus that attacks liver cells [
The Western Pacific region is well-known as an area with a very high burden of HepB, accounting for nearly half of all chronic HepB cases worldwide [
The HepB birth dose is a monovalent vaccine containing surface proteins of the HepB virus absorbed by aluminum hydroxide or monophosphoryl lipid A adjuvant [
In Vietnam, the Kinh is the main ethnic group, and other ethnic groups account for up to 14% of the national population [
Recognizing the neglected aspects of the HepB birth dose coverage across the country may contribute to developing policy to expand the prevention interventions for mother-to-child transmission of HepB virus. Exploring key socioeconomic factors that are as the barriers to the HepB birth dose vaccination could pave pathway for scaling up other specific healthcare interventions and therefore could contribute to investigation, prevention, and management of healthcare-associated HepB infections among both mothers and newborns in the community. In the present paper, we used the most updated data from the Multiple Indicators Cluster Surveys (MICS) of the United Nations International Children’s Emergency Fund (UNICEF) in the survey round of 2014 to assess the prevalence of Vietnamese children who received the birth dose of HepB vaccination and to identify socioeconomic factors associated with receipt of the birth dose.
Data from the MICS 2014 was used for this study. The MICS was conducted by the General Statistics Office in collaboration with the Ministry of Health and the Ministry of Labor, Invalids and Social Affairs. Financial and technical supports for the survey were provided by the United Nations Children’s Fund and the United Nations Population Fund. The MICS is nationally representative survey covering a broad range of issues affecting the health, development, and living conditions of Vietnamese women and children. The number of children aged 0-23 months included in the 2014 MICS was 1382 [
The main outcome variable in our study was a binary variable specifying whether a 0–23-month-old child received the first dose of HepB vaccination within 24 hours after birth. Data for the available were extracted retrospectively from the MICS 2014. In these surveys, data regarding the HepB birth dose vaccination were obtained from vaccination cards. If no vaccination card was available, the interviewers would ask mothers whether their child received a vaccination against HepB first dose vaccination [
The explanatory variables are as follows: child’s sex (male/female), low birth weight defined as less than 2,500 grams (yes/no), mother’s age (<20/20-35/36-49), mother’s education (primary or less/lower secondary/upper secondary and higher), ethnic group (Kinh/Hoa ethnicity and minority ethnic group), living area (rural/urban), and mother’s socioeconomic status.
Mother’s socioeconomic status (known as household’s socioeconomic status) was measured as an asset-based wealth index and was constructed using principal component analysis (PCA). The MICS dataset included the Household Wealth Index which was calculated by the GSO of Vietnam. The index was based on the ownership of consumer goods, dwelling characteristics, water and sanitation, and other characteristics related to household wealth. Weights (factor scores) were assigned to correspond with individual household assets [
Both descriptive and analytical methods were used in the present paper. We estimated the overall percentage of HepB birth dose vaccination among 0–23-month-old children and the percentage according to sex, region, area, ethnicity, mother’s education, and socioeconomic status. The Wald’s Chi-square test was applied to compare the differences of receiving the HepB dose vaccination within 24 hours after birth among groups. The multiple logistic regression was used for the binary primary outcome variable to explore the factors associated with HepB birth dose vaccination. The cumulative probability of being vaccinated among ethnicities at age t among ethnic groups was estimated by the inverse Kaplan–Meier survival function (or 1−SKM(t)), also known to measure the fraction of children receiving the birth dose HepB vaccination for a certain amount of time [
This study was conducted on secondary data from the MICS with all identifiable information removed. The survey had obtained informed consent from the mothers before administering survey questionnaires and the consenting process had stated that data can be analyzed in subsequent analyses without retaking informed consent. All information in the original dataset was collected confidentially.
Prevalence rates and 95% confidence intervals for receiving the birth dose of HepB vaccination in each category by the selected socioeconomic factors are presented in Table
Prevalence of receiving timely the birth dose of hepatitis B vaccination by selected socioeconomic factors among Vietnamese children aged 0–23 months, MICS 2014 (n=1382).
Characteristics | Un-weighted sample size | Weighted prevalence | Chi-Square |
---|---|---|---|
n (weighted %) | % (95%CI) | p-value | |
Sex | 0.7 | ||
Male | 741(54) | 62.3(57.6,66.7) | |
Female | 641(46) | 63.4(58.8,67.7) | |
Low birth weight | <0.01 | ||
No | 1311(95.4) | 63.8(60.2,67.3) | |
Yes | 71(4.6) | 41.6(29.2,55.2) | |
Mother’s age | <0.01 | ||
<20 | 91(5.5) | 35.3(25.0,47.3) | |
20-35 | 1131(83.4) | 64.6(60.8,68.2) | |
36-49 | 160(11.1) | 62.7(53.8,70.8) | |
Mother’s education | <0.01 | ||
Primary or less | 259(16.1) | 42.7(34.0,51.8) | |
Lower secondary | 479(36.4) | 63.6(58.6,68.4) | |
Upper secondary and tertiary | 644(47.5) | 68.9(64.5,73.1) | |
Ethnicity | <0.01 | ||
Kinh | 1062(83.7) | 69.1(65.6,72.4) | |
Minority | 320(16.3) | 30.3(23.7,37.9) | |
Area | <0.01 | ||
Urban | 526(29.8) | 69.6(64.5,74.3) | |
Rural | 856(70.2) | 59.9(55.2,64.4) | |
Mother’s wealth status | <0.01 | ||
1st quintile (poorest) | 329(19.3) | 38.6(31.3,46.4) | |
2nd quintile | 245(19.6) | 66.2(59.2,72.6) | |
3rd quintile | 250(20.1) | 62.2(55.5,68.5) | |
4th quintile | 284(21.5) | 76.7(69.8,82.4) | |
5th quintile (richest) | 274(19.5) | 68.5(62.1,74.3) | |
| |||
Overall | 1382(100) | 62.8(59.2,66.3) |
CI: confidence interval.
The two curves of cumulative proportion for children receiving the birth dose of HepB vaccination belonging to Kinh/Hoa ethnicity and belonging to minority by children age in days are shown in Figure
Cumulative proportions of receiving the birth dose of HepB vaccination by age in days among Vietnamese children belonging to Kinh/Hoa ethnicity and minority ethnic groups.
Compared with the prevalence of receiving the birth dose of HepB vaccination among children with low birth weight, the odds was twice higher for the children with normal birth weight (OR 2.13; 95%CI 1.16-3.89). Kinh/Hoa children had significantly higher odds of HepB birth dose vaccination than individuals from ethnic minorities (OR 3.15, 95%CI: 2.04–4.88). Mother’s age was significantly associated with increased prevalence of receiving the HepB birth dose vaccination for their children. Children whose mothers had higher education were significantly more likely to have had completion of the HepB birth dose vaccination compared with those had mothers experiencing primary or less education. The odds of HepB birth dose vaccination were higher in children who belonged to the families with better economic status (Table
Selected factors associated with receiving timely the birth dose of hepatitis B vaccination among children aged 0-23 months, 2014: multivariate logistic regression analysis (n=1382).
Characteristics | OR (95% CI) |
---|---|
Sex | |
Male | 1 |
Female | 1.03(0.79,1.34) |
Low birth weight | |
Yes | |
No | 2.13 |
Ethnicity | |
Minority | 1 |
Kinh/Hoa | 3.15 |
Area | |
Rural | 1 |
Urban | 1.25(0.86,1.82) |
Mother’s age | |
<20 | 1 |
20-35 | 2.24 |
36-49 | 2.17 |
Mother’s education | |
Primary or less | 1 |
Lower secondary | 1.68 |
Upper secondary and tertiary | 1.74 |
Mother’s wealth status | |
1st quintile (poorest) | 1 |
2nd quintile | 1.65 |
3rd quintile | 1.18(0.73,1.9) |
4th quintile | 2.06 |
5th quintile (richest) | 1.17(0.65,2.11) |
OR: Odd ratio; CI: confidence interval
In a Kate Whitford et al.’s report (2018), most immunization schedule in all studies included a first dose of HepB vaccine within 24 hours after birth except for one from Italy [
In our study, low birth weight children had significantly lower vaccination rates for HepB within 24 hours after birth. Saari et al. (2003) reported that vaccination rates could be affected by the infant’s birth weight [
In our study, the prevalence of receiving HepB vaccine dose within 24 hours after birth was significantly higher in urban areas than in rural areas. Previous studies in Vietnam and elsewhere also found that urban areas had higher coverage of full immunization [
In Vietnam, there is a fact that women under the age of 20, who are in attending-school age, are not able to get married and give birth later. On the other hand, a finding of Linh Cu Le et al. reported that a risk of unintended pregnancy was 1.5 times higher in Vietnamese women marrying before 20 than those later or early marriage associated with unintended pregnancy [
The findings from this study have meaningful policy implications. This is the first study that assessed the coverage of timely HepB vaccine birth dose according to socioeconomic factors using the MICS data, which are the national representative immunization survey data in Vietnam. Importantly, the resource mobilization for the immunization in Vietnam is currently limited, not meeting the demand of expanded immunization [
However, we acknowledge some limitations to this study. First, due to the limitation of the cross-sectional study design of the MICS, the results should be interpreted with caution so that they are not interpreted as implying causality. Second, the estimations of receiving HepB vaccine birth dose were derived from available information on vaccination cards and/or reported by mothers. Therefore, some children may have been vaccinated but did not have immunization card and were excluded from the study. In addition, mothers may have forgotten to report the vaccination of their children during their interviews. These would underestimate the birth dose of HepB vaccination coverage in this study. Finally, the cultural aspects related to uptake of HepB birth dose vaccination could not be assessed, such as acceptability and attitudes of Vietnamese women towards the vaccine quality.
We found that the prevalence of receiving the first dose of HepB vaccine within 24 hours after birth did not meet the target of Vietnam (the immunization coverage of HepB birth dose should reach at least 65%). It is important to continue to coordinate with the WHO to support the implementation of newborn HepB vaccination; nevertheless, the targeted interventions in vulnerable population groups including child’s low birth weight, mother’s age less than 20, mother’s low education, mother’s low socioeconomic status, and child’s ethnicity should be prioritized. There was a significant gap in the HepB vaccine birth dose coverage between the Kinh/Hoa ethnicity and minority ethnic groups, suggesting a need to improve both access and demand for HepB vaccine after birth among the other ethnic groups, in particular for minority ethnic groups living in remote and poor conditions. Furthermore, the policy developments in the HepB birth dose vaccination in particular and recommended vaccinations of the EPI in general should be established based on vulnerable populations, which leads to the sustainable interventions to decrease risk for healthcare-associated infections.
The MICS datasets existing are open to public; all users were allowed to free access after requesting to use. The raw data of the 2014 survey round of MICS was obtained with the approval to use the data for this study. UNICEF MICS encourages all users to share the research findings. The details of the MICS dataset source are described in UNICEF website (
The views expressed in this article are solely those of the authors and do not represent the official positions of the organizations the authors affiliated with.
No potential conflicts of interest were reported by the authors.
Hao Nguyen Si Anh, Hoang-Long Vo, and Vu Duy Kien designed and conceptualized the study. Hao Nguyen Si Anh analyzed the data. Hao Nguyen Si Anh, Hoang-Long Vo, Hien Tran Minh, and Ha Tran Thi Thu interpreted the results and drafted the manuscript. Vu Duy Kien and Long Hoang Bao commented and provided the important knowledge for completing the final manuscript. Long Hoang Bao edited English for the final manuscript. All authors read and approved the final manuscript.
The authors would like to thank the Global MICS team for providing them the access to the raw data of the MICS 2014 of Vietnam for this study (