Background
Early childhood vaccination is an essential, cost-effective public health measure to reduce preventable premature child mortality and childhood morbidity [
1‐
3] and contributes to lowering the spread of vaccine-preventable diseases [
4,
5]. Recognising the public health importance of immunisation, WHO launched its Expanded Programme on Immunization (EPI) in 1974, recommending a standard immunisation schedule covering tuberculosis, Bacillus Calmette–Guérin (BCG), polio, diphtheria, tetanus, pertussis, and measles [
3]. However, despite the public health benefits of immunisation, WHO estimates that based on the standard measure of the proportion of children who receive the full series of three doses of diphtheria-tetanus-pertussis vaccines by 12 months of age, over 19 million infants per year do not receive all of the recommended basic vaccines [
1]. Increasing immunisation rates, particularly in lower- and middle-income countries where the burden of vaccine-preventable disease is highest, is an ongoing public health effort [
6], prioritised by international agreements including the Sustainable Development Goals and the Global Vaccine Action Plan 2011 to 2020 [
5].
Reasons for non-vaccination relate to both the demand and supply-side determinants and include access to immunisation services and parents or caregivers understanding of benefits of vaccination compared to the risks, when to get their children vaccinated and sociocultural norms [
6‐
10]. Concerns about the safety and efficacy of vaccines and trust in the government and medical professionals has also been found to influence vaccine acceptance [
9‐
11], with individuals positioned along a continuum of complete acceptance to complete refusal [
10]. In lower- and middle-income countries, determinants of immunisation have been associated with parental education [
12‐
14], general health knowledge [
14], religious beliefs [
15,
16] and rurality [
17]. Access to healthcare services, including antenatal care (ANC) and facility-based birthing, as well as logistical challenges in reaching healthcare services, have also been found to be determinants of child vaccination [
11,
17,
18].
Situated in South-East Asia, the Lao People’s Democratic Republic is an ethnically diverse and mountainous country with a population of 6,492,228, based on the most recent census [
19]. The country is a low- to middle-income country, in the process of rapid economic development characterised by an average annual gross domestic product growth rate of 8% over the past decade, and a halving of the national poverty rate [
20]. Nevertheless, despite economic growth and improvement in many social indicators, inequities are increasing with disparities in poverty reduction and access to health and other basic services. Living in a rural area, being from an ethnic minority group or having a low level of education are particular markers of disadvantage in health outcomes [
21].
As with other indicators of social progress, the country has made significant progress in reducing maternal mortality, but at an estimated 197 per 100,000 live births (80% uncertainty interval 136–307), maternal mortality is one of the highest in the region [
22]. The under-five mortality rate has also improved, reducing from 68 deaths per 1000 live births in 2012 [
22] to 46 in 2017 [
21]. While positive, improvements are uneven and likely to be due to general socioeconomic development, especially in urban areas, increased access to skilled birth attendants and health services including immunisation, and enhanced breastfeeding practices [
20]. Achieving the Sustainable Development Goal targets in relation to reducing under-five mortality requires increased investment in evidence-based, high-impact interventions targeted at women and their families in rural areas [
20].
Childhood immunisation is a proven intervention that can protect against several communicable diseases and morbidity and mortality. Expanding coverage of the childhood immunisation programme has been a priority for the Government of the Lao People’s Democratic Republic. Poliomyelitis was eliminated in 2000 and immunisation against measles and neonatal tetanus has also increased [
21]. New vaccines for the prevention of viral hepatitis, bacterial meningitis and pneumonia have also been added to the national immunisation schedule [
23], which involves five contacts with the child (Table
1). Immunisation coverage is currently at 48% of children 12 to 23 months being fully immunised; however, this is substantially below the government’s target of 90% and is inequitable, with wealthier groups and urban families having higher levels of coverage [
20]. Furthermore, while overall coverage has increased since 2006, changes in the equity gap have plateaued [
21].
1 | Hep B BCG | < 7 days old 0–11 months |
2 | Pentavalent: diphtheria, tetanus, pertussis, Hep B, haemophilus influenza type B | 2, 4, 6 months |
3 | Oral poliovirus vaccine | 2, 4, 6, 18 months |
4 | Pneumococcal conjugate vaccine | 2, 4, 6 moths |
5 | Measles | 12 months |
In rural areas, two of the main reasons for low immunisation coverage are low uptake of facility-based birthing and high dropout rates. Some of the underlying reasons relate to demand and supply-side barriers, including the quality of immunisation services and parental knowledge and attitudes. Rural families often have limited access to reliable services and often experience negative health staff attitudes. Other supply-side failures include delays in disbursement of funds, vaccine shortages, and poor cold chain and data management [
24]. Even in urban areas where there is higher uptake of facility-based birthing, a serological study found only 6.6% of infants had protective anti-hepatitis B antibodies [
25]. The most recent Lao Social Indicator Survey reported vaccine coverage rates of 82% for BCG, 73% for Penta 1 (diphtheria, pertussis, tetanus, hepatitis B and Hib), 67% for Penta 3, 48% for pneumococcal conjugate vaccine 3, 69% for oral polio vaccine 3 and 66% for measles [
21]. Late or incomplete vaccinations have contributed to outbreaks of pertussis and diphtheria across the country [
23]. To address the gap in immunisation coverage, the Lao government is currently preparing legislation that will require children and expectant mothers to have all required vaccinations on the immunisation schedule. Effective implementation of this law requires an understanding of the supply and demand side determinants of immunisation coverage.
The purpose of this study was to examine the supply and demand side determinants that promote and constrain immunisation coverage in five villages of Sangthong District, in the Lao People’s Democratic Republic for mothers of children aged 12–23 months. More specifically, the study objectives were to describe the knowledge, attitudes and practices of mothers regarding their children’s immunisation status and identify individual and health system determinants of access to immunisation. While studies on the determinants of certain behaviours often use quantitative approaches, studies on the determinants of immunisation have frequently been qualitative [
11]. Given our research questions and that our research was exploratory, we also selected qualitative methods to enable a more in-depth nuanced understanding of the determinants of immunisation [
11].
Methods
As an exploratory study, this was a qualitative research design that used observation, interviews with healthcare workers (HCWs) and mothers with at least one child aged 12–23 months. This study design was chosen to explore, in depth, the reasons for supply- and demand-side failures in increasing immunisation coverage. In addition, a health audit was undertaken to collect data on immunisation coverage. The audit involved recording general information about the facility, the staff, vaccination stock and equipment, and provided important background information to the study.
Study sites
The study was undertaken in Sangthong District, Vientiane Capital City. The Capital City has nine districts and a population of nearly 900,000 inhabitants. Sangthong District, one of the poorest districts in the province, was selected because it has a staffed health facility that delivers immunisation services and a significant proportion of ethnic monitory groups. A cluster of five villages surrounding the health centre (HC) was selected based on the subjective assessments of key informants and local experts, based on villages they felt would provide information-rich data and where healthcare staff had expressed an interest in understanding more about the barriers to immunisation uptake in this area. Each village was approximately a 2-hour drive from the capital in the dry season. Staff at the HC and leaders in each of the selected villages were contacted in advance by the health district personnel, were advised about the nature of the study and their cooperation was sought.
Study participants
Participants were mothers with at least one child aged 12–23 months and HCWs. In each village, a purposive sampling framework was prepared to help identify potential participants who were mothers of partially immunised children and mothers of children who were fully immunised according to the EPI schedule. Immunisation status of children was established by reviewing immunisation cards held by the women, when available. In cases where the card was lost or not available, the lead researcher (LR) asked the mother to recall their child’s immunisation history from memory and the child was also checked for a BCG scar.
Mothers were identified using two recruitment strategies. The first was through the assistance of a district health nurse who introduced the field researcher (LR) to village health volunteers and traditional birth attendants in each village, who then nominated potential mothers to be invited to participate based on women who would potentially provide a rich source of data. The second recruitment strategy identified and invited eligible mothers to participate during the immunisation campaign after immunisations and supplements were given. HCWs from all four levels of the health system, who were involved in the promotion and delivery of immunisation to each of the villages, were invited to participate. Recruitment was via direct invitation to HCWs at each level and included a representative of a non-government organisation involved in district health services. In total, 10 in-depth interviews with healthcare providers and 10 with mothers were conducted. Recruitment was restricted to two mothers per village, according to the availability of the mothers who needed to return to work as well as our inclusion criteria.
Data collection
The lead researcher (LR) and the Lao-based researcher (PV) were observers taking notes as they observed education sessions and implementation of the immunisation campaign in the villages. This allowed the researchers to gain insight into how the community health outreach workers and women engaged during immunisation outreach activities and capture the context within which the different actors interacted [
26,
27]. The health audit and HCW interviews conducted at the HC provided background information to the study. The audit included reviewing HC documents including, where available, the monthly log books where immunisations should be recorded and facility observation. While we wanted to obtain coverage data from the health facilities, this was not possible as the log books were not always available or were incomplete, meaning we could not obtain reliable quantitative data from these sources. Similarly, at the village level, it was not possible to obtain coverage data as immunisation cards were often missing.
Face-to-face, in-depth, semi-structured interviews were undertaken with participating mothers (
n = 10) and HCWs (
n = 10), with a trained bilingual research assistant (PV) taking detailed notes during the interviews. The use of semi-structured interviews allowed the researchers to cover all relevant areas of interest, while still allowing some spontaneity and flexibility so that participants could raise issues of interest to them, enriching data collection [
28,
29]. The guideline used for interviewing the mothers included sociodemographic information, immunisation status of their child, knowledge, attitudes and practices towards infant immunisation, and barriers to achieving full immunisation (Additional file
1). In addition, using visual pictures of vaccines and disease cards, mothers were asked to match three vaccines (polio, measles and BCG) with the disease they prevent. The interview guide for the HCWs included general information (date/time/position of healthcare provider), information on immunisation coverage, vaccination equipment and practice, procurement and vaccine distribution barriers to the programme implementation, as well as the organisation, management and funding of immunisation services. The interviews also allowed the researchers to follow-up and clarify findings from observations and the health audit.
Prior to participating in the study, potential study participants were read a plain language statement which outlined study purpose and the voluntary nature of participation and informed consent obtained. Interviews were conducted either in English or Lao depending on participants’ preference and in a location convenient to participants. Interviews were recorded with permission and transcribed by the Lao research assistant while still in the field. As the transcripts and observational notes were written up daily by the field researchers (LR and PV), they were able to discuss preliminary results and thus respond to emerging themes in successive interviews.
Data analysis
All transcribed data was read multiple times to identify key codes and themes and capture initial meanings and patterns as they related to factors that support or deter vaccine uptake. Observational and interview data was manually coded independently by the lead investigator (LR) and guided by the research objectives [
28,
29]. The codes were merged into larger categories and themes guided by the themes outlined a priori in Table
2. These themes were identified based on our understanding of the literature and our practical experience of working in Lao People’s Democratic Republic. While themes were identified a priori, this did not prevent other themes emerging [
26,
27]. Throughout the analytic process, there was a moving back and forth between the entire dataset and the coded extracts, with interpretations checked with the research team and continuous analysis throughout the writing process [
30].
Table 2
Framework use for data analysis
Objective 1: Health systems and supply-related determinants of immunisation coverage | Issues with recording and documentation of coverage by healthcare workers Human resources Vaccine quality and supply |
Objective 2: Service utilisation and community demand-related determinants of immunisation coverage | Community knowledge Poor knowledge of effectiveness and action of immunisation Uncertainty with campaign knowledge Multiple and unclear education sources Community attitudes Inadequate handling of immunisation card Being afraid of side effects High satisfaction with service Preference for fixed site provider Access determinants Distance between health facility and village making it difficult to access services Lack of time to access services – rice fields and household duties Lack of money deterring utilisation Seasonal variation in utilisation and ease of access |
Ethical clearance
The study was approved by the research ethical committee of the University of Health Sciences, Lao People’s Democratic Republic, and the Human Research Ethics Committee of the University of Melbourne. Privacy and confidentiality were assured for the key informants to participate in this study.
Discussion
Protecting populations from vaccine-preventable diseases is shaped by interrelated supply and demand factors and actors that influence key immunisation programme outcomes such as coverage and completion of all vaccines at each of the aged-based WHO schedule points [
31]. This research explored the supply and demand factors that promote and constrain immunisation coverage in Sangthong District in the Lao People’s Democratic Republic. Several supply-side factors were identified, some of which are not unique to immunisation but are also relevant to other primary healthcare interventions and have been reported elsewhere [
18,
32,
33]. These include, for example, inadequate human resources, weak information systems, stock-outs and the capacity of district-level management for health [
32‐
34]. Other factors included the community not always being informed of outreach dates or outreach sessions conflicting with other priorities such as livelihood and households’ obligations. Given supply-side factors affect demand, general health system strengthening is likely to be an effective strategy for achieving results [
35]. Services must respond to individual and community needs in planning outreach and communities should be provided with opportunities to give input to service delivery decisions, including the timing of outreach activities. At the same time, the healthcare workforce needs to be given the autonomy and ability to adapt services to community needs.
While the HCWs generally reported that mothers and community knowledge about immunisation was ‘good’, the findings in the study suggested that mothers’ knowledge was very low and non-specific. This is of concern, as increased knowledge among families and communities has been found to be effective in increasing immunisation demand [
34,
36]. A systematic review and meta-analysis, for example, found that, in low- and middle-income countries, education was likely to be more effective than incentives in increasing uptake of vaccinations, although both were effective [
34]. Other studies in Lao People’s Democratic Republic have also suggested that poor immunisation knowledge among the Lao population is likely to negatively impact coverage [
33,
37]. Studies in Lao People’s Democratic Republic, for example, have highlighted that mothers with awareness of the diseases targeted with immunisation and the correct number of required visits to the health facility had children with significantly higher immunisation rates [
33,
38]. Also, noteworthy, is that mothers articulated a desire to better understand the reasons for immunisation and its links with disease prevention, expressing dissatisfaction with simply being told where and when the service could be accessed. Potentially, the health message has been oversimplified, with the HCWs overlooking the fact that mothers are the best carers for their children, and that they underestimate maternal ability to absorb complex information, or alternatively, they may lack the skills and resources to present complex ideas into readily understandable messages. Either way, current messages or delivery mechanisms do not seem to be meeting mother’s needs.
Currently, mothers and their families receive immunisation messages during community meetings or campaigns, in ANC visits, and from other family members or friends. A Cochrane review on the effectiveness of intervention strategies to increase and maintain high childhood immunisation coverage in lower middle-income countries found face-to-face interventions educating parents and other community members at village meetings would probably increase immunisation coverage [
6]. The review also found that the use of lay or community health workers, such as the VHWs, to promote immunisation probably increases uptake [
6]. Kaufman et al. [
7,
39], on the other hand, found little or no improvement in immunisation coverage because of face-to-face communication. A systematic review evaluating the effectiveness of interventions designed to increase access to health services for children aged over 5 years in lower- and middle-income countries found that face-to-face education can address the knowledge gap demand-side barrier [
18]. Overall, the evidence suggests that, in lower- and middle-income countries, community-based health education strategies will probably increase vaccine uptake and are likely to be more effective than facility-based health education [
6]. However, it is likely that, to be effective, face-to-face communication needs to be tailored to the particular needs and concerns of mothers and their families [
18] if financial and geographical issues that might act as barriers to immunisation are removed [
32].
The tendency of mothers to access immunisation from several providers also potentially presents barriers to both the functioning of the health system and consumer knowledge. The HCWs felt that this ‘provider shopping’ was creating difficulties with coverage data recording and data sharing within the district. Provider shopping has been reported elsewhere in rural Lao People’s Democratic Republic, with few people using only one provider [
40]. Not having a single entity responsible for delivering immunisation to the community may also result in a lack of responsibility for tracking and following up of children who are not recorded to be fully immunised, especially as vaccination records are often lost and the health information system is weak [
41,
42]. This ‘smorgasbord’ of providers could be confusing for consumers, diluting the why, when and where of immunisation services. Some of the mothers, for example, seemed confused about immunisation accessibility and many were uncertain about whether they should wait for outreach at the village or seek immunisation elsewhere. Not knowing when the outreach teams were going to visit, or if they were coming when their child’s immunisation was scheduled, added to this uncertainty. This could be alleviated by household visits and provision of information before delivery, especially to families with lower levels of education [
33]. With increasing access to mobile phone technology, text messages may also help to improve uptake of child health services, including immunisation [
43].
A positive association has been identified between the possession of an immunisation card and immunisation status [
36]. While the link is not clear, it could be that the presence of an immunisation card acts as a cue for the mother [
36]. However, in this study several of the mothers did not have an immunisation card, highlighting the need for service providers to maintain a supply of cards, to ensure that these are provided to women and that women are educated on keeping the card in safe place and bring it with them when they take their infant to healthcare or community outreach services. Not being in possession of a vaccine card makes it hard for HCWs to determine an infant’s immunisation status, with oral report often accepted instead, but a poor correlation of verbal recall and serological immunity has been observed and may result in over-reporting [
44]. Our results also suggest that HC data is either not available or incomplete, making it difficult to monitor and supervise immunisation services. To improve data management, HC staff needs further training and support in the execution of data management tasks.
he association between facility-based birthing and immunisation has been well-documented [
36]. While not specifically examined in this study, demand for facility-based birthing in Lao People’s Democratic Republic and especially in rural areas remains low, and promoting ANC, facility-based birthing and postnatal care should continue to be a major strategy in improving child health [
22]. Additionally, it is important to continue community outreach and promoting immunisation to mothers and their families given that a substantial proportion of women continue, for various reasons, to prefer giving birth at home [
45,
46]. Another longer-term strategy to improve immunisation coverage is continuing to increase women’s literacy, including health literacy, through formal education but also through social networks [
33,
47,
48]. Mother’s education, for example, has been positively correlated with immunisation; literate mothers, for example, may have more knowledge of immunisation, including target diseases and the immunisation schedule [
33]. A study in India demonstrated a positive relationship between the proportion of literate females in a district and a child’s complete immunisation status within that district [
47]. However, Cui and Gofin [
48] found no association with mother’s education and child immunisation but noted that most of the participants in their study had low levels of education.
Another finding of this study is that a basic readiness to deliver immunisation services is important, but not necessarily enough on its own and investment is required in both supply and demand-side factors [
34,
35]. While programmes to increase immunisation coverage have often focussed on supply-side factors, such as vaccine supply and cold chain management, and community-outreach to reduce geographical and financial barriers, some households were still missed as community-outreach teams did not go beyond the village centre. Provision of HCW training, including in ‘soft skills’ such as communication, may also help to address the supply-side barrier of acceptability and have indeed been effective elsewhere in increasing immunisation uptake [
43]. Ultimately, both demand- and supply-side interventions are needed as increases in demand cannot be effective if supply-side constraints limit provision of vaccines [
34,
49,
50].
As with all research, this study has some limitations that need to be acknowledged. Firstly, the study was conducted in one district, and is not representative of the country. Nevertheless, the study was not intended to be representative but was rather undertaken to qualitatively better understand persistent low immunisation coverage in Lao People’s Democratic Republic. Secondly, the interviews were undertaken using translation and inevitably some of the nuance has been lost and may have limited the depth of responses from participants. To mitigate this, a constant checking back and forth with interpreters was undertaken as well as triangulation of field notes, observations and interviews with community members and health staff. While we had initially wanted to estimate immunisation coverage based on health facility log-books, this was not possible due to missing data and monthly log books not always being retained. In addition, at the village level, in the absence of immunisation cards, the study also relied on recall. However, a population survey in Tanzania found parental recall of child immunisation was relatively good, being only slightly overestimated possibly due to social desirability bias, compared to a card-based checks [
51].
To conclude, while impressive gains have been made in reducing infant mortality and increasing immunisation coverage, persistent inequalities remain. Increasing requires a focus on both supply and demand side factors, as well as broader socioeconomic intervention, including providing education to women and their families encouraging them to be active agents of their own and their children’s preventative health-seeking behaviour. Further research is also needed to better understand the pathways to improving immunisation uptake and how to build on strengths revealed in this study that may be supporting immunisation coverage, such as recent attempts to address supervision of HCWs in delivering immunisation and HCWs’ positive attitude towards helping their community. Further qualitative and quantitative work is also needed to better understand the interplay between the different supply- and demand-side factors and the relative importance of each. Comparison between districts with high immunisation coverage is also warranted to help to identify successful pathways to improving coverage.