Current challenges and proposed solutions to the effective implementation of the RTS, S/AS01 Malaria Vaccine Program in sub-Saharan Africa: A systematic review

Abstract

BackgroundThe Malaria Vaccine Implementation Program, coordinated by the World Health Organization, intended to initiate the roll-out of the RTS, S/AS01 malaria vaccine in 3 sub-Saharan African countries in 2018. With sub-optimal implementation, the effectiveness of this vaccine in routine clinical use could be significantly lower than its measured efficacy in randomized trials. This study had as objectives to systematically review and summarize published studies addressing the challenges faced during the implementation phase of malaria vaccination programs and randomized trials conducted in sub-Saharan Africa. The review also sought to report proposed solutions to the challenges identified.MethodThis was a systematic review of studies published between 1947 and 2017. Medline, Embase and the Cochrane library databases were searched. Of the 365 studies retrieved, 8 eligible studies reported on challenges of implementing a malaria vaccine in sub-Saharan Africa and possible solutions to these challenges. Data were abstracted from the eligible studies and a qualitative synthesis was done.ResultsThe 8 studies included in the review had a total of 6189 participants and used a variety of methodologies (3 qualitative, 1 quantitative, 3 mixed method studies and 1 clinical trial review). There was an overall positive acceptance towards the new malaria vaccine (n = 6/8 studies), with a mean acceptance rate of 86.1% (95% CI: 62.0–110.2, n = 2). The main challenges to vaccine receptivity were: inadequate community engagement due to lack of information about the vaccine (n = 6), fear of the vaccine’s side effects (n = 5), inefficient delivery of vaccination services to children (n = 4), and sub-optimal quality of the health services (n = 3). Main themes identified from the proposed solutions consisted of the following: using dynamic communication models and trusted sources for delivering vaccine-related health information to the communities (n = 6), community engagement at both national and district level (n = 6), implementing the new vaccine services alongside the existing health services already delivered (n = 6).Conclusion/RecommendationsEffective implementation of the malaria vaccine program requires careful consideration of the socio-cultural context of each community. The RTS, S/AS01 malaria vaccine acceptance and uptake may be significantly enhanced if caregivers’ perceptions about vaccines and their importance are adequately fine-tuned. In order to achieve these, community participation and the provision of adequate information in an acceptable form via reliable communication channels seem to be imperative.

Immunization with full-length Plasmodium falciparum merozoite surface protein 1 is safe and elicits functional cytophilic antibodies in a randomized first-in-human trial

“…7 Although great effort has been invested in the identification of protective antigens, previous vaccination strategies have generally been unsatisfactory and only the pre-erythrocytic vaccine RTS,S (Mosquirix TM , GSK Bio), based on the P. falciparum circumsporozoite antigen, is under pilot implementation studies in three African countries. [8][9][10][11] Nonetheless, its efficacy is moderate and short-lived (39% reduction in overall malaria incidence and 31.5% in life-threatening complications over a follow-up period of 48 months in children who received four injections 12,13 ), possibly due to a decay in complement-fixing antibodies. 14 An antigen that has been widely considered as a component of a malaria vaccine is the P. falciparum merozoite surface protein 1 (MSP1).…”

Genetic polymorphism of Plasmodium falciparum circumsporozoite protein on Bioko Island, Equatorial Guinea and global comparative analysis

“…RTS,S/AS01 vaccine is a pre-erythrocytic stage vaccine based on the P. falciparum circumsporozoite protein (PfCSP) [4,5]. In 2015, the European Medicines Agency for the immunization of children against malaria approved the RTS, S/AS01 vaccine [6] and the phase 3 clinical trials conducted in various sites in Africa showed that the RTS, S/AS01 vaccine has a protective e cacy of 45% in children in the rst twenty months after vaccination [7,8]. In 2018, the World Health Organization through a large-scale pilot malaria vaccine implementation program (MVIP) aimed to introduce this vaccine in three sub-Saharan countries (Ghana, Kenya, Malawi) [6].…”

“…In 2015, the European Medicines Agency for the immunization of children against malaria approved the RTS, S/AS01 vaccine [6] and the phase 3 clinical trials conducted in various sites in Africa showed that the RTS, S/AS01 vaccine has a protective e cacy of 45% in children in the rst twenty months after vaccination [7,8]. In 2018, the World Health Organization through a large-scale pilot malaria vaccine implementation program (MVIP) aimed to introduce this vaccine in three sub-Saharan countries (Ghana, Kenya, Malawi) [6]. Besides of RTS,S/AS01, a live attenuated Plasmodium falciparum whole sporozoite (SPZ) vaccine is also regarded as a great potential malarial vaccine.…”

A qualitative analysis of vaccine decisionmakers’ conceptualization and fostering of ‘community engagement’ in India

“…This may be especially useful in overcoming communities' myths and fears about new vaccines, which are often considerably more expensive than existing ones, and target relatively 'hidden' diseases [31,32]. However, current CE evidence is limited to a few systematic examinations focused on community counselling and vaccination campaigns, often in pockets of high vaccine resistance and low vaccination coverage [33,34]. These reviews have also focused on public opposition rather than involvement, and no data have been collected to indicate if and how communities are engaged beyond individuals' decisions to vaccinate themselves and their children [35,36,37].…”