The immunisation preparedness process in Africa and Senegal

In August 2020, the WHO Africa office established a COVID-19 Vaccine Readiness and Delivery Task Force, with support from Africa CDC. In preparation for the roll-out, countries were invited to develop immunisation plans covering coordination, financing, legislation, logistics and cold chain, pharmacovigilance, evaluation, and ‘demand generation’. African countries were provided with a Vaccine Readiness Assessment Tool (VIRAT), to be used by ministries of health with support from WHO and UNICEF. Aspects to be evaluated included regulations, planning and coordination, costing and funding, target populations, delivery strategies, supply chain, human resources, vaccine acceptance and uptake, safety monitoring, and immunisation monitoring (WHO, 2020b). By the time the vaccines were expected in late 2020, many countries were considered not ready for a mass COVID-19 vaccination campaign or ‘ill-prepared’, according to experts and based on self-evaluation by VIRAT. In January 2021, this tool showed an average score of 35% for the continent, instead of the expected 80% (Ekwebelem et al., Reference Ekwebelem, Yunusa, Onyeaka, Ekwebelem and Nnorom-Dike2021). Among technical issues, experts stressed the need to involve populations, to develop access strategies for high-risk and vulnerable populations, and to address concrete concerns of populations such as procedures and risks attached to vaccination (Ekwebelem et al., Reference Ekwebelem, Yunusa, Onyeaka, Ekwebelem and Nnorom-Dike2021).

Senegal completed the preparedness self-assessment process with the VIRAT tool in October 2020, and results showed that the country was ‘prepared’ for 60% of the sections, ‘preparing’ for 37%, and ‘unprepared’ for 3%. The Ministry of Health launched a technical group, engaged with COVAX for free supply of vaccines up to 20% of the target number of doses (and supply at reduced cost beyond 20% depending on availability), with technical assistance and support for cold chain procurement. Strategic choices were defined: priority targets were people over 60 years of age, those with comorbidities (hypertension, diabetes, and other chronic diseases), and frontline health workers; vaccine types/brands were to be selected on the basis of safety, efficacy, conservation standards, number of doses required, and packaging; they would be delivered by the Expanded Program on Immunization (EPI) and community health workers since no regular immunisation was offered at that time to adults by the health system. A roadmap was established, and the main challenges were identified as the availability of vaccines, adherence of the population and health workers to vaccination, mobilisation of domestic resources, and the successful introduction of vaccines and pharmacovigilance.

The first ‘COVID-19 Vaccination Plan’ was released in January 2021(Ministère de la Santé et de l’Action Sociale, République du Sénégal, Reference Ridde and Faye2021). Costs per dose were estimated at between USD 4 for the Covishield (Oxford–AstraZeneca) vaccine and USD 72 for the Sinopharm vaccine excluding consumables (syringes, safety boxes) associated with the vaccines. Covishield vaccines were obtained free of charge through the COVAX Facility and within its limits; some vaccines were the subject of bilateral donations, others would be purchased by the country, and some of them with the support of AVAT. Senegal’s goal was to vaccinate, in two phases, 20% of the population (in the priority population) by June 2021 and 90% of the population by July 2022. To achieve this, in addition to training health professionals, it planned to raise awareness among ‘organised groups, networks, and civil society organisations’, but the communication plan was not explained in detail.

Nexus 1. Uncertainty of vaccine supply

At the end of 2020, the Senegalese authorities wanted to have vaccines as quickly as possible, so an agreement was reached with China for the supply of 200,000 doses of the Sinopharm vaccine. These doses made it possible to launch the vaccination campaign on 23 February 2021, supplemented 10 days later by Oxford–AstraZeneca vaccines provided by COVAX, part of the 1.2 million doses expected (International Vaccine Access Center, VIEW-hub 2022). Senegal was thus the first West African country to begin a mass vaccination campaign with a great deal of publicity showing political, medical, and religious authorities, including President Macky Sall, receiving their injections. Frontline health workers were vaccinated at their workplaces. The capital’s health centres, where the vaccines were first given, were besieged by people who had seen the media coverage and queued up until the daily allotments of vaccines were exhausted. Facility health staff announced the prioritisation criteria of people over 60 years of age and with chronic diseases to the queues. Three weeks later, the desire to respond to requests and the availability of vaccines led authorities to open up vaccination to adults and adolescents in the general population.

To complete primary vaccination, both Covishield and Sinopharm vaccines require a second dose after 3 months. However, the expected additional doses were not delivered by COVAX, following the ban of Covishield exports from India during the country’s own outbreak crisis. In early May 2021, it was reported that Senegal had administered all the doses it had received so far. Senegal felt forced to turn to other suppliers for the Johnson & Johnson, then Pfizer vaccines, when they became available. Vaccine supply remained highly erratic and insufficient until September 2021, with at least two periods from several weeks to 2 months when health facilities had stock-outs and were unable to meet demand, even for people from priority populations. There were also a few periods when only one type of vaccine was available, making it impossible to comply with the primary immunisation protocol based on two injections of the same type of vaccine. From February to September 2021, about half of vaccines were supplied through bilateral channels, either through donations or commercial contracts, and the other half by COVAX, with less than 5% through AVAT. The balance between channels has subsequently changed. By February 2023, all COVID-19 vaccines had been supplied first by COVAX (83.92%), while AVAT and bilateral channels accounted for 8.15% and 7.92%, respectively (Africa CDC, 2023).

The health authorities responsible for planning the vaccine supply and immunisation campaign faced uncertainty, first about the dates, types, and amounts of vaccines available and second about the capacity for production of biomedical equipment and transport facilities, under the severe constraints of cold chain and vaccine storage temperature. The decision to contract a supplier also involved taking into account the scientific information available on each vaccine type, which remained very limited for some. Bilateral contracting was also linked to geopolitical considerations and prior economic relationships, as were vaccine donations with political implications. Global structural inequalities not only delayed but reinforced uncertainties about vaccine supply with consequences for later stages, including vaccine distribution and delivery.

From June to August 2021 during the third epidemic wave due to the Delta variant (Mathieu et al., Reference Mathieu, Ritchie, Rodés-Guirao, Appel, Giattino, Hasell, Macdonald, Dattani, Beltekian, Ortiz-Ospina and Roser2020), numerous cases and deaths, particularly of publicly known people, increased risk awareness in the population. Despite the establishment by the Ministry of Health of an online platform to identify the people in the priority categories willing to be vaccinated and manage demand, requests for vaccination at times exceeded these categories. Targeting vaccination to priority populations was jeopardised by the lack of information in health services, where the authors observed health workers negotiating on-the-spot contradictions between vaccine recommendations and a lack of vaccines. Individuals who the authors interviewed described strategies to obtain a first or second dose: many mobilised their social capital to get into a vaccination site sometimes far from their home but with vaccines available or followed long routes from one vaccination site to another without being able to find a dose. Finally, many people reported getting tired of obstacles and abandoning their search for vaccination. ‘I came three times for my second dose and three times there was no vaccine, I wasted my working time, I’m not coming back’ (Man, 31–40, vaccinated with one dose), one man explained.

Supply difficulties gradually faded in 2021 and by 2022 had transformed into uncertainty about the country’s capacity to use the vaccines in stock and therefore about the quantities to be ordered. In addition, regulatory and reallocation delays led to shortened periods of expiry for vaccines. This combined with delays in donors’ decisions and management created another constraint and became a matter for protest by public health officials at the regional level (Africa Union et al., 2021; Afolabi et al., Reference Afolabi, Wariri, Saidu, Otu, Omoleke, Ebenso, Adebiyi, Ooko, Ahinkorah, Ameyaw, Seidu, Agogo, Nomhwange, Salami, Mohammed and Yaya2021; Feinmann, Reference Feinmann2021; Barnéoud, Reference Barnéoud2022). Finally, these difficulties reflected the social effects of ‘uncertainty’ as defined in Stirling’s ‘incertitude’ model (Reference Stirling1999), such as the changing concerns for health authorities from supply lack to excess and the entanglement for populations between vaccine access and demand.

Nexus 2. Ambiguity about the aims of immunisation

While official communication on COVID-19 vaccines in Senegal began with the launch of the vaccination campaign in February 2021, these vaccines had already been the subject of intense informal communication on the internet and social networks in West Africa for almost a year. This lay communication focused on the meaning of vaccination in Africa and articulated two notions that circulated in Senegal and in French-speaking West Africa. First, suspicions spread around Africa’s use as a research laboratory by Westerners who want to test vaccines on the continent for their own benefit. This notion was already well established before the pandemic as a legacy of the colonial period and fuelled by experience with research for other vaccines like hepatitis B that had been conducted on the continent without benefiting the population (Moulin et al., Reference Moulin, Chabrol, Ouvrier, Delaunay, Desclaux and Sokhna2018). A second notion suggested that Africans were minimally vulnerable to COVID-19, either through ‘natural resistance’ or owing to African pharmacopoeia. Both ideas were widely spread among the people the authors interviewed in Dakar in October 2020, the majority of whom stated that they would refuse vaccination.

On 1 April 2020, two medical doctors raised the possibility of setting up studies on the protective efficacy of the bacille Calmette-Guerin (BCG) vaccine against COVID-19 infection among sex workers in Africa on LCI (La Chaine Info), a French international TV channel. This discussion, which did not consider ethical issues nor previous controversies about medical research among sex workers in Cameroon (Folayan and Peterson, Reference Folayan and Peterson2020), provoked a great deal of protest in French-speaking Africa and among the African diaspora in Europe. Several petitions based on the idea that white doctors wanted to take advantage of the vulnerability of sex workers and consider Africans as guinea pigs were shared on social networks by celebrities, including footballers and other personalities popular with young people. A few voices pointed out that BCG research had already begun on other continents, that sex workers are vulnerable people who need support and a better knowledge of the COVID-19 protection available to them, and that vaccine research is needed for vaccine ownership by African populations (Eboko, Reference Eboko2020). This controversy reinforced the perception that vaccine trials are implemented in Africa by Westerners for their own good, motivated by structural racism. The ‘LCI doctors case’ revived memories of colonial management of epidemics, where injections – whether vaccines or treatments – left painful scars (White, Reference White2000; Lachenal, Reference Lachenal2017; Tilley, Reference Tilley2020; Leach et al., Reference Leach, MacGregor, Akello, Babawo, Baluku, Desclaux, Grant, Kamara, Nyakoi, Parker, Richards, Mokuwa, Okello, Sams and Sow2022b). As one man explained, ‘Even if COVID did exist, I’d say it’s more to do with a world order or a vaccine trial they want to impose on Africa’ (Man, trainer, 41–50 years, not vaccinated).

Meanwhile, from February to March 2020, the Senegalese population was exposed to images of African students living in China who survived the disease in a context where death was shown to be ‘around any corner’. Comments in the media claimed that the virus was defeated by Africans thanks to their biological resistance. ‘African resistance’ combined with ‘African treatments’ for prevention and care was also mentioned to explain that in Senegal, the population experienced mild pandemic waves with a limited number of cases and less than 500 deaths in 2020. In parallel, the limited effects of the pandemic in Africa, contrary to the predicted catastrophe, became a matter of discussion among scientists and global health experts at the global and regional level where reasons for this so-called ‘paradox’ were under scrutiny (Ghosh et al., Reference Ghosh, Bernstein and Mersha2020).

In February 2020, Professor Raoult, a French microbiologist, began to promote chloroquine on YouTube as a treatment that would quickly put an end to the pandemic (Institut Hospitalo-Universitaire Méditerranée Infection, 2020). His discourse gained particular traction in Senegal, not only owing to his legitimacy as a medical authority but also because of his connection with the country due to his childhood residence in Dakar and to the work of the Franco-Senegalese research team on infectious diseases he had led over the past decades. The popularity of chloroquine as an accessible and familiar treatment, used against malaria until the 1990s, shaped the social perception of COVID-19 as a ‘malaria-like disease’, less exceptional in reality than it was considered by political authorities (Desclaux, Reference Desclaux2020; Kadiri and Ollivier, Reference Kadiri and Ollivier2020).

Later, the promotion in Senegal (as in other African countries) of Covid-Organics, a remedy championed by the President of Madagascar as a compound containing Artemisia, reinforced the trivialisation of COVID-19 as prevented by a local and renowned popular anti-malarial drug. These perceptions of COVID-19 were explicit in the interviews the authors conducted in Dakar in October 2020 with people from varied social backgrounds. Many respondents mentioned that, given the limited severity of the disease for Africans and the availability of local preventive treatments, a COVID-19 vaccine was unnecessary in Africa. This reinforced the idea that vaccines had been introduced only for testing, to be provided later in developed countries where they were urgently needed. Some people also implied that vaccine provision aimed at discrediting African pharmacopoeia treatments. As one man described, ‘No need for [vaccines]. Islam and traditional remedies are highly effective’ (Man, security guard, over 60, not vaccinated).

Meanwhile, social networks relayed global messages, most of them also salient on other continents (Johnson et al., Reference Johnson, Velásquez, Restrepo, Leahy, Gabriel, El Oud, Zheng, Manrique, Wuchty and Lupu2020): they suggested that the pandemic was caused by global actors who have either deliberately spread a virus or disseminated false news about the epidemic and its vaccine as a weapon to achieve undeclared goals. These messages were interpreted and/or adapted in Africa, reinforcing other messages in Senegal that were sometimes relayed by online media or traditional press. They intersected with earlier perceptions of global health as a field of exploitation of Africans by powerful institutions or individuals to extract biological or monetary resources, to dominate populations, or to conduct experiments. Some global messages, such as Bill Gates’ Reference Gates2015 talk about the need for pandemic preparedness (Gates, Reference Gates2015), were transformed to indicate nefarious intent. In this case, the presumed goal of population control through 5G chips injected with a vaccine resonated with locally constructed online messages about white doctors injecting the virus into children in Casamance (Southern Senegal region). By mid-2020, the public’s perception of the threat partly shifted from the COVID-19 pandemic to the COVID-19 vaccine.

Although new and more concrete concerns about the vaccine emerged when the vaccination campaign was launched in February 2021, and demand for the vaccine increased during the third wave of the pandemic, ‘ambiguity’ as defined by Stirling (Reference Stirling1999) remained, underlying social discourses. The theme of political connections and conspiracy developed, targeting the president of Senegal for his relationship with Bill Gates and with governments from the Global North supposed to dictate the vaccine policy, in a context of political contestation at the national level. For some, vaccines remained a ‘political weapon’ used against the promotion of local African solutions to COVID-19 (such as African preventive remedies, including chloroquine) or for population control by national or global powers. These uncertainties about the purpose of vaccination were fed by the puzzled perceptions of an outbreak that provoked merely 2000 deaths in 2 years but brought disproportionate economic effects, hidden profits derived at various levels, and a justification for a state of emergency that lasted long after the initial epidemic wave.

Nexus 3. Uncertainty on vaccine side effects

For people who had a biomedical understanding of vaccines, including first-line health professionals, vaccine safety was a concern for two reasons: adverse events and the rapid expiration of doses. The increase in demand experienced at the beginning of vaccination lasted until March 2021, when the first reports of adverse events from the Oxford–AstraZeneca vaccine appeared in the global media. This information was broadcast by the international news channels during this period and widely relayed by the Senegalese media. Cases of atypical venous thrombosis had been reported after vaccination, particularly in France and Great Britain and most frequently in young women. These effects were in addition to temporary pains and swelling at the injection point and the short but severe flu-like symptoms experienced by people of any age. WHO still recommended vaccination, considering that its preventive benefit outweighed the thrombotic risk. Several European countries soon suspended the dispensation of adenovirus-based vaccines while the level of risk was assessed but reopened it again with age limits varying from 30 to 70, according to their group priorities and national vaccine availability. International channels broadcast this information as a series of breaking news, with apparently contradictory decisions linked to procurement in European countries, echoed in the authors’ interviews with people in Senegal who expressed their anxieties about adverse events at any age.

This information had a major impact on vaccine perceptions by introducing doubt, in particular among health professionals who were getting their first injections or waiting for their second. They began to wonder if the benefit of the vaccine was greater than the risk of COVID-19, which was then perceived as low in Senegal. This question rekindled other anxieties related to the relatively short development time of the COVID-19 vaccine, which many professionals, as well as the general population, considered insufficient for the vaccine to be safe. Interviews showed that the suspensions of delivery were interpreted as proof of danger. Anxiety was also relayed on social networks about vaccines involving genetic manipulations, based on confusion between vaccine technologies. Among the first-line health workers the authors interviewed in April 2021 in Dakar, some expressed disappointment and distrust of the health authorities and the vaccine manufacturers, who they explained had neglected or hidden data on adverse events. ‘At the moment, there’s talk of vaccination, but people don’t trust it because of rumours about AstraZeneca (vaccine)’s side effects’ (Woman, health worker, 31–40, not vaccinated). Some health workers were accused of knowing about these risks and threatened by people who were anxious about symptoms or death after vaccination.

The absence of scientific information about adverse events associated with the Sinopharm vaccine led some people to consider it safer than others and request the ‘Chinese vaccine’, especially for their second injection. The donations and COVAX supply of Oxford–AstraZeneca were interpreted by part of the population as coming from the stocks of vaccines that Western countries no longer wanted to use, as shown in online comments of articles. These perceptions were reinforced by an administrative measure applied from June 2021, when France refused entry to its territory for people vaccinated with the Covishield vaccine supplied by COVAX but accepted those vaccinated with Vaxzevria, though these brand names referred to the same technology. Maintained for several months and explained by different approvals from the European Medicines Agency, this measure was also perceived as proof that COVAX vaccines were less effective or more risky than other vaccines, an interpretation developed and disseminated through anti-vaccine posts on YouTube by anti-Western militants such as Nathalie Yamb, called ‘La dame de Sotchi’ (Yamb Reference Yambn.d.). Social networks also disseminated messages about deaths as adverse effects of the vaccine that were not supported by scientific knowledge.

At the national level in Senegal, the local press first mentioned ‘adverse events’ in reports of deaths that occurred immediately or within hours after an injection (Fall, Reference Fall2021). This wording was not challenged by the Ministry of Health, although the causal relationship of vaccines to these events had not been established at the time of publication. The surveillance of adverse events following immunisation (AEFIs) was part of the national immunisation strategy, as requested to qualify for COVAX Facility supply (WHO and UNICEF, 2021). However, the authors’ field observations show that vaccinators avoided communicating about adverse effects to people coming for vaccination, either because they lacked information themselves or because they feared provoking refusal or mistrust. Thus, vaccinated people were not aware that they should report post-immunisation symptoms to health workers who would then transmit this information to a committee to investigate the relationship between the event and the vaccine.

The poor performance of the pharmacovigilance system which had registered less than 70 AEFIs by the end of June 2021, a lack of knowledge by health workers, and difficulty in implementing the first reporting level among the public, alongside the uncontrolled allegations by the media about unchecked cases, converged to maintain uncertainty about the adverse effects observed in Senegal. This added to the ignorance or lack of consideration by the media for the pharmacovigilance process and to the lack of communication from health authorities. These shortcomings described in Senegal are also related to the overall limitations of management systems for medical information and have been observed in other African countries (WHO, 2020b; TDR, 2021).

In September 2021, when vaccine uptake was no longer limited by supply, the publication in the media of the number of expired doses that were to be destroyed (20,000 in September and 200,000 in October) (Diop, Reference Diop2021) fuelled additional concerns about vaccine safety. WHO had previously introduced a regional scheme to redistribute doses between countries and encouraged their use beyond the expiry date (BBC News, 2021), but this measure was not very reassuring for populations that were often already critical towards this international organisation suspected of not defending the interests of Africans. The authors’ media surveillance data show that this contributed to safety concerns expressed on social networks, where the destruction of expired doses in Nigeria was shown as a victory obtained by the population against Western institutions (Associated Press, 2021).

The authors’ discussions with health professionals in 2021 showed the importance these individuals gave to the ‘adverse events’ that they experienced themselves or learned about from others. Media publication and the lack of medical communication about risk, which increased collective awareness and experience of mild symptoms, fed into uncertainty and anxiety about more severe unspoken troubles. Concerns about the adverse effects of the Oxford–AstraZeneca vaccine led some health professionals to prefer the Sinopharm vaccine for themselves and loved ones since it had been less targeted by the media. However, the health professionals the authors interviewed did not seem ready to actively recommend any vaccine, particularly Oxford–AstraZeneca, in view of their uncertainties and reservations, which were shared by community actors when COVAX again delivered this vaccine to the country. For all stakeholders, this situation would have been qualified as a combination of ‘ignorance’ and ‘uncertainty’ according to Stirling’s model (Reference Stirling1999).

Nexus 4. Uncertainty about the relevance of vaccination strategy

From September 2021, the Ministry of Health maintained its vaccination strategy, mainly based on the AstraZeneca vaccine now supplied in significant quantities by COVAX. The virus had already circulated widely and conferred immunity on a proportion of the population who had experienced asymptomatic or mildly symptomatic forms of the disease. At the regional level, a meta-analysis of seroprevalence estimation studies in Africa performed in September 2021 suggested ‘that up to 65% of the population have some level of conferred immunity’ (Balde et al., Reference Balde, Oyugi, Karamagi, Okeibunor, Conteh, Ejiofor, Atuhebwe, Nanyunja, Diallo, Mihigo, Yoti, Braka and Gueye2022). After examining various scenarios that included the possibility of re-infection, the authors, mainly experts at WHO, concluded that it was necessary to continue vaccination efforts. Studies at the national and regional levels were in phase with the WHO strategy published in October 2021, which endorsed the targets of full vaccination coverage for 40% of the population by the end of 2021 and 70% by mid-2022 (WHO, 2021; Diarra et al., Reference Diarra, Kebir, Talla, Barry, Faye, Louati, Opatowski, Diop, Consortium, White, Loucoubar and Miled2022).

For key actors in Senegal, the strategy raised questions expressed in discussions and meetings among experts and health professionals. Should individuals with antibodies (or neutralising antibodies) be vaccinated? The existing scientific evidence on the benefits of vaccinating people who had already acquired immunity through infection did not seem convincing, the efficacy of immunity that was acquired ‘naturally’ was still unknown, and there was no simple and inexpensive way to test people to see if they had immunity before vaccination. They also questioned the appropriateness of providing a vaccine that was not adapted to the circulating variant. There were still major uncertainties about the benefit and cost-effectiveness of a vaccination strategy that targeted 70% of the general population, compared to priority groups. Other unanswered questions about the vaccination strategy included the immunological value of revaccinating every 6 months rather than vaccinating with an appropriate booster when a new wave is announced. This situation would have been qualified as ‘ignorance’ according to Stirling’s (Reference Stirling1999) ‘incertitude’ model.

A national medical expert explained during an interview that strategies must take into account the needs perceived by the population: if vaccination was imposed to achieve 70% coverage, mainly because resources were available at a time when the population did not perceive the need, the population might be reluctant to receive boosters later when a new variant would make a mass campaign essential. Some resident and diaspora experts challenged policy choices and gave their own perceptions through online articles on blogs or national media. Actors explained in discussions that they did not find sufficient elements in recent scientific knowledge to define a strategy that seemed relevant, effective, and safe, as well as adapted to Senegal, without endangering the necessary bond of trust with the population.

Some called for a regional reconsideration of the 70% objective of vaccination coverage in the general population, which seemed too demanding in terms of resources, logistics, and compliance by the population for a temporary and unproven benefit (Msellati et al., Reference Msellati, Sow, Desclaux, Cottrell, Diallo, Le, Harczi, Alfa, Touré and Manigart2022). Others argued that the objective of the national strategy was to avoid wasting the doses already received in order to avoid disappointing international donors. These issues raised questions on the capacity to define strategies adapted to the regional level, as stated by one interview respondent:

In another interview, a Senegalese expert on epidemic response raised these questions and pointed out Africa’s ‘non-existence in the environment of pharmaceutical research’ as a limitation to its autonomy in defining strategies adapted to this region, as he shared in publications (Bousso, Reference Bousso2022; Bousso, Reference Bousso2023). The regional expert review (Balde et al., Reference Balde, Oyugi, Karamagi, Okeibunor, Conteh, Ejiofor, Atuhebwe, Nanyunja, Diallo, Mihigo, Yoti, Braka and Gueye2022) argued that while some research informed the response based on serological surveys and operational studies in Africa, more fundamental research is needed to understand the particularities of the African context, particularly related to herd immunocompetence.

These persistent uncertainties about the relevance of the national versus international strategy and about Senegal’s capacity to achieve out-of-reach goals could, at least in part, explain the inconsistent commitment of health authorities to promoting immunisation. Communication campaigns were limited, as were strategies to reach people in each vulnerable priority population. The authors’ data show that by late 2022, scientific uncertainty about the appropriate strategy for building herd immunity in Senegal combined became entangled with a pragmatic attitude regarding the increasing level of infection-acquired immunity and ‘fatigue’ about COVID-19 measures due to the long duration of the pandemic.

The need to prioritise recovery and immunisation for other diseases like measles and cholera may have also relegated COVID-19 vaccination to the background of the national immunisation policy. However in 2023, the rate of coverage by boosters was high in a limited proportion of the population who had a primary injection (53%), probably those who were compelled to be vaccinated for work or travel and who had sufficient social capital, information, and connections to the health system. For scientific and medical experts conveyed in regular meetings by the regional coordination platform on COVID-19, these uncertainties stemmed from a lack of research in Africa, which they attributed to

Global/regional/local assemblages as sources of uncertainty

Uncertainties themselves possess concrete features produced by ‘complex, non-linear unpredictable systems’ (Scoones and Stirling, Reference Scoones and Stirling2020, p.4). The four areas of uncertainty (supply, meaning and aims, side effects, and vaccination strategy) found by this research correspond to different forms of knowledge, engaged and questioned at different times at national, regional, and global levels. Uncertainties about supply related to the inequitable global order of vaccine production reflected the interplay at the national level between economic, political, scientific, and organisational decision-making factors in the context of multiple constraints and competing and vested interests. They also resulted in the inability to plan and deliver vaccines according to a predefined schedule between February and August 2021.

The resulting practical difficulties for vaccine seekers obliged the development of complex and time-consuming strategies at high cost and shaped perceptions of COVID-19 immunisation as a difficult service to obtain. This uncertainty has been described as ‘material’ in the sense that it is attached to objects, whose production depends on multiple variables and actors (Goumri, Reference Goumri2021). This form of uncertainty has also been experienced to a lesser extent in high-income countries where it was more brief and limited. In West African countries, these ‘external forces’ were beyond the capacity of preparation at the national level and needed long-term institutional development at the regional level (establishing vaccine production in Africa and technology transfer and setting up regulatory frameworks).

Uncertainties based on coexisting perceptions about the purpose of vaccination as well as about the meaning of COVID-19, ‘ambiguity’ according to Stirling’s framework, were a major element in the constitution of social representations of COVID-19 vaccination in the Senegalese population from April 2020 onwards. The perception of the exploitation of African bodies for experimentation through vaccination was also described in other French-speaking African countries such as Burkina Faso, Benin, Cameroon (Desclaux and Sow, Reference Desclaux and Sow2021), and Guinea (Heyerdahl et al., Reference Heyerdahl, Le Marcis, Nguyen, Alenichev, Camara and Grietens2023), spread through online social networks.

Tilley (Reference Tilley2020) describes how the perception of being treated as guinea pigs in medical interventions is rooted in the memory of the colonial past and still active conceptions of racial hierarchy. The lack of trust described by respondents seemed to be fed by limited awareness about African research and the contributions of African scientists to medical knowledge, resulting in particular from media that presents global scientific research as Western. In social media, actors from the West African diaspora in Europe made connections with global discourses on the conspiracies by powerful individuals and states to dominate populations in Africa and beyond. Seeing these representations articulated within an African identity discourse, political authorities in several West African countries were convinced to oppose vaccines and research for several months.

Although vaccines are known to be the subject of multilevel anxieties and conflicting discourses in all contexts (Leach and Fairhead, Reference Leach and Fairhead2007; Larson, Reference Larson2020), preparedness for the COVID-19 pandemic did not include any communication about vaccines before the immunisation campaign began in Senegal – 10 months after the first public celebrities had already spoken up against vaccination. In the meantime, in a context of scientific uncertainty about future vaccines and intense global circulation of adverse representations, a whole range of semantics was offered to individuals to create meaning from vaccination uncertainty and ambiguity.

Uncertainty about vaccine safety among health professionals was fuelled by information broadcast by international news channels from March 2021, before the vaccines were available and without adaptation for an African audience. The first adverse events were described in priority groups in Western populations with high frequencies of chronic disease and advanced age and were presented as vaccine-related rather than population-related, on the basis of a generalisation from a Western population treated as a universal reference. For healthcare workers in Senegal, who were among the first to be vaccinated and who got their information mainly from the international media before training was provided by the Ministry of Health, these data resonated with personal experience.

Without pharmacovigilance data published at the national level to oppose alarmist global information, precise information on the risks associated with vaccines was poorly shared in Senegal. This local ignorance remained despite the recent development in Africa of pharmacovigilance mechanisms that made scientific knowledge on side effects available. Public communication had not been prepared, despite the awareness of the iatrogenic risk that has become more important for the public in its relationship to medicines during the last decades (Badji and Desclaux, Reference Badji and Desclaux2015).

Uncertainties among public health experts concerning vaccine strategy and its relevance in the aftermath of the third wave also concerned the transition of the pandemic to an endemic mode that could justify a change in vaccine strategy. These uncertainties about the appropriate vaccine strategy are fuelled by the lack of scientific data, that is, ‘ignorance’ according to Stirling’s framework, in the context of ‘the African paradox’ (Ghosh et al., Reference Ghosh, Bernstein and Mersha2020). They highlight issues of sovereignty regarding research in Africa and the unequal availability of resources for research. They also raise concerns about the global underinvestment in basic research among African populations when such research could provide scientific knowledge of global interest.

Pandemic preparation and the COVID-19 action plan in Senegal focused on the implementation of a global immunisation strategy based on principles and hypotheses with limited scientific knowledge. Several limitations and uncertainties related to COVID-19 immunisation found in Senegal were also salient in other West African countries, such as Sierra Leone (Leach et al., Reference Leach, MacGregor, Akello, Babawo, Baluku, Desclaux, Grant, Kamara, Nyakoi, Parker, Richards, Mokuwa, Okello, Sams and Sow2022b). These seem to relate to the connection between policy and strategy set at the global and regional levels and the capacity for implementation and subsequent agency located at the national level.

Forms of uncertainty and anticipation for preparedness

Beyond the unpredictability of the epidemic and inevitable organisational constraints, various forms of uncertainty related to vaccination were at stake for different social groups. Besides health authorities and vaccinators, material uncertainty concerned planning, access, and the quality of vaccines available. For the population, ambiguities were embedded in perceptions about the relevance and the benefits/dangers attached to the vaccines. For health agents, interpretations of quickly evolving global medical information that emphasised probabilistic AEFI risk interacted with body experiences and fed uncertainty and anxiety in the absence of factual information from the national level. For national public health experts, a vaccination strategy based on insufficient scientific knowledge and underconsidered African specificity (i.e. scientific ‘ignorance’) was too questionable to be applied broadly and directly. These heterogeneous forms of uncertainty related to material ignorance about supply, doubts, and ambiguity among coexisting contradictory perceptions about the aims of vaccination, the embodiment of the probabilistic notion of risk about vaccine side effects, and the insecurity of decisions made when scientific knowledge about vaccination strategy relied on ‘known unknowns’.

Some challenges could have been anticipated at the national level before COVID-19 vaccination began in Senegal, not necessarily from other countries’ experiences, but because they were related to long-standing structural rather than COVID-19-specific drivers. The challenges in perceptions and adherence to vaccines are increasingly a matter of concern in public health and the social sciences. Examining these challenges can inform interventions co-developed with communities to fight conspiracy and anti-vax theories, as part of preparation, that is, before the beginning of the pandemic. The socially constructed meaning given to the risk of COVID-19 and its vaccination could have been better addressed with the population through more participative communication and detailed information. In addition, concerns among health professionals about vaccines’ side effects could have been better managed through communication on pharmacovigilance data registered at the national level.

Critically reconsidering the experience of previous epidemic and pandemic response efforts with those concerned who faced similar challenges, particularly during the peak of HIV/AID (Jaiswal et al., Reference Jaiswal, LoSchiavo and Perlman2020), could be an efficient way to promote local expertise, as shown by some experiences during the Ebola epidemic (Richards, Reference Richards2016; Hofman and Au, Reference Hofman and Au2017). This approach requires a reconsideration of the ‘expert’ mode of preparedness assessment (beyond medico-centric approaches based on metrics) and the development of complementary qualitative assessments of context-related issues and structural interventions, to be defined in a multisectoral and multidisciplinary way. Information transparency, a key factor for trust especially during a crisis (Adhikari et al., Reference Adhikari, Yeong Cheah and von Seidlein2022), should not only concern scientific data and risk expectations but also decision processes for public health and their limitations (Hirsch, Reference Hirsch2022). These processes can be anticipated with a better connection between preparation and research to manage ongoing updates of scientific knowledge.