Past experiences with cholera outbreaks created high awareness and fear of cholera in this remote area in South-Eastern DRC. Health education and the provision of clean water have curbed cholera incidence to some extent, but resources were lacking to maintain protected wells and boreholes and diarrhoeal illness continues to impinge on the population. This is the background to the high acceptability of an oral cholera vaccine in this cholera-endemic area. The high willingness to pay may somewhat overestimate respondents’ actual ability to pay (hypothetical bias) . Cost-related barriers have been repeatedly reported to negatively affect vaccine acceptance [16, 24, 27, 38–40]. That costs may play a role in the study sites as well is supported by the fact that respondents who considered the loss of income in case of cholera a problem were less likely to anticipate OCV acceptance if a higher cost would have to be met. Efforts to reach the most vulnerable people may therefore be required if equity in access is to be achieved. Factors linked to a vaccination campaign itself, such as opening hours, could not be assessed in absence of a campaign but may affect uptake as well, as a similar study conducted in Zanzibar showed [41, 42].
Our results equally showed that respondents who feared the social impact of cholera, such as interference with social relationships, were less likely to anticipate OCV acceptance This may seem counter-intuitive at first sight because we would expect a person who fears the consequences of cholera to be more interested in prevention. But the fear of losing social support because of cholera needs to be understood in this context of broader social insecurity. In African settings access to resources is usually mediated by group membership, mainly the family, or clan. Where formal social security is lacking, group membership is often the only way for the poor to mobilise material support during a crisis such as illness . Investments in social networks are important coping strategies . The lower anticipated OCV acceptance of respondents who stress the social implications of cholera may reflect their material insecurity and weak social networks rather than their reluctance to use a vaccine. Prior research has come to similar conclusions. Cassell et al. (2006) reported from Gambia that mothers with a weak social network were less able to access childhood vaccination .
In our study fishermen and their families were more likely to anticipate social and financial implications of cholera. In the unadjusted analysis they were also less likely to anticipate acceptance of an OCV at the highest cost, even if their monthly income was not lower as compared to others. Fishermen often live under difficult conditions. Already in the 1990s van Bergen had described a ‘poverty-complex’ of poor living conditions, frequent migration, disrupted social structures, and problems around alcohol consumption and sexual transactions providing a breeding ground for both HIV and cholera in the fishing camps of lake Mweru . An agency report from 2009 confirms that for example poverty-related fish-for-sex exchange in Kasenga and the surrounding fishing camps are locally perceived a problem and a cause of HIV in the area . HIV and poverty have been described to be a problem in fishing villages in other settings in the region as well [47–49]. The lower acceptability of a vaccine at a high cost among fishermen in the unadjusted analysis is therefore likely to be explained through greater social and economic vulnerability in the multivariable models. The identification of vulnerable subgroups such as the fishermen and fish traders may help to improve equity in access to a vaccination campaign, because there is often a predisposition to neglect difficult-to-reach people out of logistic reasons especially if herd protection may already be achieved by a relatively low coverage as was shown to be the case for cholera .
A process of social marginalization can be reinforced if a feared disease is thought to be the problem of a particular group of people. To explain the effects of both negative impact and concern about stigma of cholera on anticipated vaccine acceptance, one may consider reluctance to accept a vaccine as a kind of anticipatory coping with dreaded social exclusion and stigma by denying vulnerability to cholera. Negative attitudes of health professionals towards poor and marginalized people may additionally compromise acceptance of a vaccine. In other contexts a patronising and disrespectful treatment by health professionals has been shown to discourage especially poor and marginalised persons from using (childhood) vaccination services [20, 27].
On the individual level, education and information about vaccination are known to influence vaccine acceptance [51, 52]. In our study education influenced OCV acceptability at a lower price as well, while at a higher price material insecurity became more important. But cholera-related knowledge influenced vaccine acceptability irrespective of the price. In Zanzibar, where a similar study was conducted, individual-level barriers to OCV acceptance during a mass vaccination campaign included unawareness of the infectious pathways and symptoms of cholera as well . It was notable that local illness beliefs, like witchcraft or the breach of a taboo, were not associated with OCV acceptability in DRC. Other research in Ghana found as well that traditional practices had no influence on the readiness to use vaccines . Hence local traditional health beliefs and practices do not necessarily compete with science-based approaches. Nonetheless there is a possibility of underreporting of traditional beliefs and practices in our study, and delayed treatment-seeking because of witchcraft beliefs might still be a problem even if the acceptability of a vaccine is not compromised.
Besides traditional beliefs, Christian religious practices were common, without being mutually exclusive. In contrast to traditional beliefs, faith-based practices – namely praying for healing and the belief that God was responsible for cholera outbreaks – did show an effect on anticipated OCV acceptance, however in a contradictory way. The literature mentions an ambiguous influence of religion on health-related behaviour as well. Religiosity has been associated with a higher sense of control over one’s health . Conversely, prevention such as vaccinations may be perceived as interfering with God’s plans . Similarly ambiguous were the findings in this study. Prayers for healing, which are positively associated with OCV acceptability, may on the one hand indicate more active coping with health problems at the individual level and reflect active church membership and a strong social support network. On the other hand, respondents who mentioned God’s will to be at the origin of cholera were less likely to anticipate OCV acceptance. Persons who lack agency and autonomy in particular have been shown to ascribe to fatalistic positions . They may be less optimistic about their participation in a vaccination campaign, which too, may play a role for vaccine acceptability.
Limitations of the study
Household selection took place at random, and only two persons per site refused to participate in the study. Nonetheless, a potential underreporting or misreporting of local practices for treatment and prevention due to the negative connotation of these practices within the health system cannot be excluded (desirability bias). But witchcraft beliefs for example, which were common in the area, were not negatively associated with anticipated acceptance, suggesting that traditional medical beliefs and practices are not necessarily a barrier to vaccine acceptability. Nonetheless these results should be interpreted with caution. Witchcraft narratives were often linked to local authorities and politicians, suggesting limited trust in government or other authority. As the cross-sectional study did not include questions related to quality of care or trust in healthcare providers this could not be further investigated.