Barriers to childhood immunization in sub-Saharan Africa: A systematic review

The study employed Preferred Reporting Items for Systematic Reviews and Meta- Analysis (PRSMA) guidelines [57]. We performed electronic searches of articles included in this systematic review from the Web of Science, PubMed/Medline and EMBASE from January, 1988 to December, 2019. We combined the following terms: (child or children or childhood or infant or baby or newborn), and (immunization or immunisation or vaccination or vaccine or immunity), and (barrier or hesitant or refuse or refusal or delay or denial or denier or denied or concern or reason or doubt “non-acceptance” or incomplete or obstacle or constraint), and (“Sub Saharan Africa” or Angola or Benin or Botswana or “Burkina Faso” or Burundi or “Cabo Verde” or Cameroon or “Central African Republic” or Chad or Comoros or Congo or “Cote d’Ivoire” or “Equatorial Guinea” or Eritrea or Ethiopia or Gabon or Gambia or Ghana or Guinea or “Guinea- Bissau” or Kenya or Lesotho or Liberia or Madagascar or Malawi or Mali or Mauritania or Mauritius or Mozambique or Namibia or Niger or Nigeria or Rwanda or Senegal or Sierra Leone or Somalia or “South Africa” or “South Sudan” or Sudan or Tanzania or Togo or Uganda or Zambia or Zimbabwe) [See supplementary materials 1].

We restricted to published articles in English that focused on childhood immunization barriers, conducted in Sub-Saharan Africa from January 1988 to December 2019. Articles were excluded if: (i) focused on barriers to immunization for children in other regions of the world, (ii) studied adult immunization barriers (iii) published before December, 1988 and beyond December, 2019; (iv) they were editorials, (v) reports, (vi) review articles, (vii) supplement articles, (vii) bulletins and (ix) studies not available on the university library. We included only observational studies in this systematic review.

Search result items were uploaded into EndNote X7 library. Duplicates were removed. JBB and DQ did the initial screening (title and abstract) and full texts of articles based on the inclusion and exclusion criteria. We resolved disagreements with third review (FO). The study employed narrative synthesis. The author uses the following approaches: tabulation and thematic analysis. The analysis focus on thematically grouping the barriers identified in the included studies. Researchers formulated table to capture descriptive information and data for each include study. This includes author, year, geographical location and number of countries included in a study; participants and demographic; study design; reported national immunization coverage, data source, date; study quality; and key reported barriers. JBB synthesized data and created table with input from LC and SX. JBB and LC classified reported barriers into three major categories: barriers confronting the parents/caretakers, those specific to the health system, and those linked to the providers. Discrepancies were resolved by consensus after discussions.

JBB and DQ assessed articles for methodological quality independently based on modified tool designed to assess quantitative and qualitative studies used in a similar study published elsewhere [58]. [See supplementary materials 2] It included a range of items from 1 to 14. Each item scores one point. Based on the scores, we grouped articles into three: low, moderate and high; articles scored 12 points and above were considered high methodological quality, moderate 8 to11 points,7 points and below were low. If ratings differed, we discussed the article in an effort to arrive at a consensus (Fig. 1).

In this systematic review, several cited parental/caretaker’ barriers were modifiable (knowledge, misconception, trust, delivery at home, long waiting time, providers’ hostility, parent’s forgetfulness, inconvenient time and language barrier). Parental/caretaker barriers are factors that impede mothers/caretakers progress in the process of their child accessing and utilizing vaccine services. It was revealed that parent perception influenced immunization of their children [1, 12‐14, 21, 34‐44, 48, 49]. Parents not being knowledgeable of immunization was the most frequently and consistently reported barrier to childhood immunization [2‐40, 42, 44, 45, 47‐50, 52]. Wiysonge et al. (2012) stated that “low parental knowledge of immunization and/or lack of access to information about childhood immunization could be an important contributor to the high burden of unimmunized children in sub-Saharan Africa”. Four studies [3, 13, 25, 26], noted that a child born to a mother with little or no knowledge of vaccination may not complete the required vaccine series. Two articles reported that delay on vaccine birth doses is associated with maternal education [18, 20]. Misconceptions about childhood immunization were recorded as major hindrance to effective utilization of immunization services in this review [1, 2, 11‐14, 21, 22, 29, 31, 32, 48, 49] One article [17] reported that some parents believed that the immunity induced by vaccines is less effective than that of the natural disease, and they prefer to endure the diseases than immunization. Some caregivers were reported to believe in the efficacy of traditional medicines as an alternative to immunization and concomitant treatment by traditional healers [31, 35].

Lack of trust towards vaccines was a major reported barrier. Some community members were reported to refuse immunization services due to the belief that vaccines were ‘harmful’, ‘expired’ and could cause ‘physical disability’ and/or ‘death’ among their children [2, 17, 21, 22, 30, 32, 33, 35, 38, 45, 48, 53]. The place of delivery of a baby was reported as determinants of full immunization of a child. Delivery at health facility enhances full immunization [18, 20, 22, 27, 28, 40, 48]. Long waiting time at health facilities was frequently and consistency noted [11, 12, 31, 35, 36, 45]. Two articles [35, 53], noted that parents sometimes forgot the appointment date for the next immunization visit of their children. Others reported place/time for vaccination being unknown [11]. Inconvenient immunization time such as on weekend/public holidays was reported as a barrier [43, 54]. One study [3], indicated language as a barrier to childhood immunization.

On the other hand, we also recorded non-modifiable childhood immunization barriers of parents/caretakers. Those categorized as unmodifiable are factors that are extrinsic to the parent / provider dyad. These include occupation, financial limitations, place of residence of mother/caretaker, religion, ethnicity, family size, male partners’ support, and migration; seasonal farm work, feeling ashamed of poverty-associated reasons, and being a single mother. The role of male partners in the decision for childhood vaccination was an important barrier noted. Male partners were often cited as being against vaccinating the children. The decision for immunization was generally a joint decision between the mother and father of the child. But it was noted with strong emphasis that women were in charge of taking children for immunization and sometimes the husbands opposed immunization and stopped their wives from immunizing their children by denying them the social and financial support necessary [3, 16, 17, 22, 33, 38]. The nature of occupation of the mother/caretaker was reported as a major determinant to childhood immunization [1, 11, 14, 15, 21, 22, 25, 30]. Housewives were reported to have complied with higher coverage of full immunization status than other occupations such as merchants or public/private employees [11]. Also, mothers/caretakers were reported to be affected by seasonal factors. One study [1] stated that, “usually in the first quarter of the year in which most mothers engaged in coffee-collection and processing in coffee processing industries often did not bring their children to the next immunization schedule”. Financial limitation was a major barrier cited that hinder childhood immunization [7, 11, 13, 15, 17, 24, 27, 34, 36, 38, 40, 42, 45, 47, 50, 52]. The place of residence of the mother was reported as determinants of full immunization of a child [37, 39, 41]. One study noted that the likelihood of vaccination of a child by day 7 is higher among children residing in rural areas than those in urban and pre-urban settings [18]. Socio-cultural factors and religion were noted to have negatively impacted immunization uptake [12, 18, 19, 22, 23, 37, 48]. Ethnicity and cultural beliefs were reported barriers to vaccine utilization and coverage; certain ethnic groups within the same country were identified with low coverage. Family size was associated with the probability of a child being fully immunized. It was revealed that children from large families have low vaccine uptakes, considering the burden of other children at home in taking up immunization services [11, 13, 25, 46, 50]. Migration was also cited as a hindrance to childhood immunization coverage [30, 35, 44, 48]. Feeling ashamed of poverty-associated reasons was reported as barrier. Schwarz et al. (2009) indicated that “mothers who felt that they could not dress smartly enough for the approval of other women at the clinic were less likely to attend” [24]. Babirye et al. (2011) further revealed that “poor mothers often felt stigmatized and bullied from other women and health workers if they did not show up in good clothing” [17] Being a single mother was also a cited barrier to childhood immunization in this review [37].

We noted health system barriers in this review. We describe health system barriers as inherent factors that obstruct the process of delivering vaccine and vaccine related services to it beneficiaries. These includes broken cold chain, irregular supplies and distribution of vaccines; limited human resource and infrastructures, and long distances separating health facilities from families [1‐3, 11, 13‐16, 19, 22, 23, 25, 29, 32, 35, 43, 44, 47‐52]. Vaccine shortages at health facility level and difficulties of transporting vaccines were commonly reported to significantly hinder immunization services [1–174 3,11,14,16,19,22,23,25,33,43,47,48,52,51]. Some facilities were reported to have utilized vaccine refrigerators from nearby health centers due to poor working condition of theirs [1, 3, 32]. It was noted that due to staff limitation, only one staff often conducted immunization sessions in the catchment population [2, 3, 11, 25]. Studies [11, 13, 45, 47‐50, 52, 53] also revealed that some hard-to-reach areas do not have health facilities nearby to provide childhood immunization. Health workers were reported to covers long distances on outreach services due to inadequate health centers [11, 13, 15, 43]. It was also reported that, caretakers covered long distances to reach immunization centers resulted to non-completion of vaccination series [2, 3, 13, 18, 21‐26, 31, 36, 38, 40‐43, 46]. Some studies [11, 13, 18, 26] attempted to analyze the associations of distance with immunization outcomes. Tefera et al. (2018) indicated that “families whose home was at least an hour from the vaccination site were less likely to be fully vaccinated (56%) than families whose home was between 30 and 59 min away (67%)”. According to Miyahara et al. 2016, “the longer the distance from vaccination site, the lower the chances of vaccination by day 7 (of life) of a child”. Poor arrangement and coordination of immunization seasons at health center level were identified as barrier [16, 38, 43, 45].

In addition to the parental and health system barriers mentioned above, providers were identified as possessing barriers to immunization. Providers’ barriers are those factors that limit the process of health service providers to fully provide vaccine services to it beneficiaries. These factors include the lack of knowledge of vaccine indications and contraindications and the lack of counseling skills [3, 16, 43, 52]. The restricted vaccine opening policy (use of multi-dose vials and the limited time for their use) was noted as a barrier specifically for the BCG vaccine [18, 30, 43]. It was also cited that reminders were not sent on time about routine immunization or outreach days [48] Providers’ hostility and rude attitudes to mothers were also a reported immunization barriers in this review [15, 16, 24, 30‐33, 36, 45, 52, 53].

Our study acknowledged and outlined few limitations. As most literatures cited are observational in nature, this study cannot confirm causation nor completely rule out confounding. A few studies also relied on survey data [7, 12, 18, 27, 37, 40, 41] with the potential for selection or nonresponse bias. Population-based data studies may be liable to misclassification or measurement error, leading to information biases. Retrospective studies of caretakers/parents beliefs are subject to recall bias. Lack of protocol registration of this review may limit the evidence to demonstrate that, components of the research plan have been fully addressed. The review also lack grey literature/unpublished literature searching with potential for publication bias. Majority of the studies were conducted in East Africa [1, 3, 11‐13, 16, 17, 19‐21, 25, 27, 28, 32, 34, 38, 43, 44] and West Africa [1, 15, 18, 22‐24, 29‐31, 33, 36, 37, 39‐42, 45, 46] limiting generalizability to the rest of the continent. A quantitative meta-analysis from these studies may have been useful for analyzing quantitative trends, although the heterogeneity of the studies precluded such analyses.