Public sentiments towards the use of Wolbachia-Aedes technology in Singapore

The use of Wolbachia strategy to suppress vector populations is a novel approach, which has the potential to reduce mosquito populations and the risk of mosquito-borne disease transmission [1, 2]. This approach, commonly known as the Incompatible Insect Technique (IIT), is a species-specific and benign approach for controlling vector populations [3]. Eggs produced from the successful mating between released male Wolbachia-carrying Aedes aegypti (Wolbachia-Aedes) mosquitoes and urban female Aedes aegypti mosquitoes in the environment (without Wolbachia) are non-viable, due to Cytoplasmic Incompatibility (CI), therefore suppression of mosquito populations could be achieved with regular releases over time [3, 4].

Field studies are necessary to demonstrate that the male Wolbachia-Aedes mosquitoes behave in the same way as they do in the laboratory, when subjected to environmental conditions in the field. The potential of using this strategy was first demonstrated in the suppression of Culex pipiens in Myanmar [5]. Improved technology in recent years made the microinjection of Wolbachia strains into mosquito species possible [6], allowing exploitation of the Wolbachia strategy for suppressing populations of mosquito species [7‐9]. Numerous field trials have been reported recently, including successful population suppression of the Polynesian tiger mosquito, Aedes polynesiensis, in French Polynesia [10]; Aedes albopictus in China [11‐13] and in the United States [14]; and Aedes aegypti in the United States [15], in Australia [16], as well as in Thailand [17]. To test the effectiveness of the Wolbachia-Aedes suppression approach, a multi-phased field study – named ‘Project Wolbachia – Singapore’ – was launched in 2016 by the National Environment Agency (NEA), a statutory board under the Ministry of Sustainability and the Environment (MSE) [previously known as the Ministry of the Environment and Water Resources, MEWR], Government of Singapore. This population suppression approach involves the release of male Wolbachia-Aedes mosquitoes in a high-rise and densely built urban environment.

Many such field trials acknowledge the complexities and challenges that come with politics and ethics, hence the importance of both community and government support are emphasised, in addition to high scientific quality [18]. With public consultations and engagement deemed critical for successful implementation of the Wolbachia-Aedes technology, several authors have recommended strategies for effective community engagement [18‐22]. These strategies include understanding the socio-political context of the local population, close engagement with local communities informing them of the study, and periodic update of the project [16, 23].

In Singapore, extensive stakeholder engagement regarding the use of the Wolbachia-Aedes suppression approach was planned and put in place, prior to any possible field releases [24]. Early consultations with key relevant stakeholder groups – such as local and international academia, scientists, medical doctors, the local nature society, specific interest groups, community leaders, and residents at the selected study sites – allowed the identification of risks and understanding of community concerns, to help shape key public communications messaging and gain early support from these important groups. During project implementation, detailed information and timely updates were regularly provided through various channels, including: publicity banners and posters placed at strategic locations with high footfall at the study sites; educational brochures prepared in Singapore’s four official languages (English, Mandarin, Malay and Tamil) distributed to every single household/ other premises within the study sites; and regular, detailed informational updates provided via mainstream (print and online) media, social media, as well as NEA’s Project Wolbachia – Singapore webpage. Besides the dissemination of information, Learning Journeys to NEA’s Mosquito Production Facility, sharing sessions at schools and childcare centres, and mass outreach sessions via roadshows for the general public, were regularly conducted face-to-face, to generate awareness and understanding. Another key aspect of Singapore’s engagement strategy was ensuring a transparent and responsive feedback system to address concerns in the community – including via telephone hotline, email, an online reporting system, and verbal feedback to NEA field officers on the ground – which were crucial for maintaining trust with, and accountability to, our stakeholders.

Enhanced community engagement for the understanding of Wolbachia technology does not necessarily equate to public approval and acceptance. In several field studies, an individual informed-consent approach was adopted, and releases were done only at sites where authorisation was obtained from households in the community [16, 25]. While this approach is plausible for a small-scale field study, it is challenging for large-scale deployment [26].

To understand public acceptance and sentiments towards the use of Wolbachia-Aedes technology in Singapore, we adopted several public sentiment survey approaches, including online, face-to-face in streets, as well as door-to-door household surveys. Herein, we examined the public’s awareness of dengue, and the public’s opinion towards the use of Wolbachia-Aedes technology prior to the first field releases conducted in October 2016, as well as the perception of residents at the study sites in the interim of the first project phase. The association of social-demographic characteristics, knowledge and attitude of the public towards the release of male Wolbachia-Aedes were analysed. The surveys conducted also served as one of the channels for accountability to residents and stakeholders, gathering feedback from the community, and addressing residents’ concerns.

Understanding the public’s concerns and sentiments provided invaluable insights on how to better engage residents and stakeholders in the community, to generate awareness and understanding of the Wolbachia technology, and address any feedback and concerns. Results from the online survey conducted before the first releases and trialling implementation of the Wolbachia technology in the small-scale field study, suggested that a small proportion of individuals may feel complacent and stop trying to prevent mosquito breeding with the implementation of Wolbachia technology [29, 30]. This led us to highlight the importance of continued individual efforts in preventing mosquito breeding as one of the key messages, during extensive community engagement efforts at the study sites before the first releases and small-scale field study began.

From the survey data, we gleaned insights on the awareness and attitudes towards dengue among the online respondents in Singapore, as well as from the residents living at specific study sites. About 88% of the online survey respondents, and 68 to 77% of the residents at the selected study sites (BH, TW and NSE), perceived dengue as a serious problem in Singapore. 73% of the online survey respondents, and about 66 to 80% of the residents at the selected study sites, felt that the Government’s efforts to control dengue in Singapore were adequate. Studies done in other countries among urban populations revealed similar high levels of agreement that dengue is a serious disease, such as in Yemen (97.7%) and India (89%) [31, 32]. In the current study, social-demography, such as education level, had an influence in the level of awareness of dengue among the respondents. Therefore, easy-to-remember educational campaigns on dengue prevention would be most beneficial in reaching out to this small group of the population who are less educated, narrowing the knowledge gap in the awareness of dengue. Good knowledge on the risk of dengue would contribute towards greater motivation to carry out dengue control measures at the individual and community levels, as well as for greater support towards the Government’s efforts, such as using Wolbachia technology, in controlling dengue. In addition, educational campaigns leveraging the fear element would only be effective if the perceived threat is strong [33].

In this paper, we describe a high level of receptivity towards the use of Wolbachia-Aedes technology as a promising control tool to suppress the Aedes aegypti mosquito vector population in Singapore, gleaned from the various public sentiment surveys conducted by the team. This high level of receptivity may be attributed to a high level of trust felt by the general public towards the Government of Singapore. In a recent study conducted by the Institute of Policy Studies (IPS) Social Lab, a high level of confidence in the Government of Singapore was reported, ranking second highest amongst studies conducted in 12 other countries [34]. Particularly in the area of handling public health, it was reported that Singaporeans place a lot of trust in, and are satisfied with, the Government of Singapore, despite there sometimes being low levels of knowledge in this area amongst the respondents [35].

Sixty-nine to 88% of the respondents interviewed in the study had heard of Project Wolbachia – Singapore, with the majority of respondents (32 to 56%) hearing of the project through mainstream media (print and broadcast media) and publicity materials (23 to 33%). Similar findings have also been reported elsewhere, where mass media such as television and newspaper were identified as the major sources of public health information [36, 37]. However, a survey done in Singapore showed that digital news and social media platforms are growing in popularity due to the convenience of mobile devices, with majority relying on digital platforms of key news media for quick, timely and accurate information [38]. As such, updates on the project at various key milestones continued to be provided via various media channels, including mainstream media, to keep residents well informed about the progress of the project. Information was also regularly made available on the NEA webpage, as well as via digital and social media platforms.

Another limitation to consider was administering of the household perception survey, which was done during working hours, when many residents would have been at work and thus away from their homes. Thus the household survey done at the study sites may have been biased towards residents who were present at home during the day, such as homemakers. Nevertheless, the persons interviewed could actually have most adequately represented the general sentiments of the public towards the release of male Wolbachia-Aedes mosquitoes, as they would have been the ones most likely experiencing the increase in number of male Wolbachia-Aedes mosquitoes around their neighbourhoods, since the mosquito releases were carried out during the day.

As the project progressed, a subsequent survey was planned, to explore sentiments in greater detail, and to understand the knowledge, attitudes and outcomes using implicit question types. This would provide an understanding of whether there were any changes to the support from residents after two years of project implementation, and would provide insights on any difference in perception of the project at newer areas to which the project was expanded. Understanding of community perception would help guide subsequent educational campaigns and publicity.

The various surveys conducted provided a good understanding of the public acceptance and sentiments towards the use of Wolbachia-Aedes technology in Singapore. The majority of residents at the study sites had heard of the ongoing Project Wolbachia – Singapore, involving the novel approach of releasing male Wolbachia-Aedes mosquitoes, which was a testament to the project team’s efforts in putting out extensive public communications and intensely engaging the community via a multitude of platforms. The surveys also revealed that the majority of the Singapore population recognises the seriousness of dengue, although a small proportion of the community does not perceive the high risk of dengue, which suggests the need for educational campaigns on the risk of dengue to be more visual, less wordy, and easier to remember. As the project scales up in subsequent phases, there is a need for longitudinal studies to understand how residents’ perception and behaviour change over time, and also for in-depth surveys to better identify gaps in the knowledge and practices related to the prevention of dengue.