Vaccine Safety in the Next Decade: Why We Need New Modes of Trust Building

"...if not taken seriously and addressed promptly, perceptions of risk will not only persist, but will keep growing..."

Vaccine Confidence Project data indicate that public confidence in vaccine safety is consistently lower than overall confidence in the importance of vaccines. The rise of internet-mediated communication has had a significant impact on how fast public safety concerns can spread, especially when videos and even text sent through social media can provoke heightened emotions. While some of the public concerns and anxieties about vaccine safety are driven by rumours and misinformation, vaccines do have small risks. When trust in government, in local health systems, or in international stakeholders is weak, perceptions of even the smallest risks are amplified. To better anticipate and address rapidly shared vaccine safety concerns, efforts such as the World Health Organization (WHO)'s Vaccine Safety Net (VSN) initiative are working to increase awareness about vaccines and to build confidence in vaccines. This article reviews vaccine safety issues and efforts.

Despite scientific evidence of the safety of a particular vaccine, perceptions and anxieties can strongly affect individual and group vaccination decisions. One of the more recently characterised vaccine safety issues, "immunisation stress-related-response" (ISRR), has gained particularly high visibility. Clusters of immunisation stress-related responses following immunisation have been registered in countries such as Denmark, Japan, and Colombia. One single incident in Pakistan during a polio mass immunisation campaign in 2019 caused mass contagion, and hundreds of children were rushed to the hospital with complaints of abdominal pain, vomiting, and fainting following polio vaccination - triggering angry protesters to burn down a healthcare facility. While a vaccine may be assessed as having no causal link to adverse events, the experience of vaccination can play a role in triggering stress-related responses following immunisation. These symptoms need attention in order to mitigate individual and public anxiety, as clusters of reactions following vaccination can disrupt immunisation programmes, impact overall public trust in immunisation, and negatively affect vaccine coverage.

As noted here: "A friendly, confident, relaxed approach with empathy and supportive communication to build trust with the vaccine recipient and caregiver will be key to mitigate the occurrence of ISRR...To respond to clusters of ISRR at a programme level, it is important for immunisation programmes and relevant staff have a clear pre-established communications strategy to decide if, when and what needs to be communicated should ISRR occur. When clusters of such events occur, they should be thoroughly investigated, causality assessed and stakeholders - including the media, healthcare providers and public - should be kept informed to mitigate the spread of unfounded rumours. Monitoring public sentiment across social media, if feasible, can be helpful to detect and guide emerging misinformation at the nascent phase before it spreads..."

The article reviews interventions to build and sustain vaccine confidence. For instance, the aforementioned VSN reviews websites around the world to assess their quality and accuracy to ensure and promote access to trustworthy and science-based online information on vaccine safety. Newly qualified VSN websites are authorised to host a VSN visual identity (icon) on their homepage to signal to visitors that they are accessing a safe place for trusted vaccine information. These websites hail from different parts of the world and are available in multiple languages. This diversity allows for culturally sensitive material, tailored to local contexts, that takes into consideration the audience's interests and health literacy. It is estimated that 2 million new users are accessing information made available by VSN members every month; in 2020, some 72 million pages were viewed on VSN websites. Increasing VSN Network visibility through social media networks has also been crucial.

In conclusion: "Public perceptions and concerns around vaccine safety are unlikely to be redressed in a letter or rebuttal to a scientific Journal, but by understanding what is driving public anxieties and sentiments to better address them....While social media has amplified fears, anxieties and uncertainties, social media can also be successfully used to listen to and engage publics in positive ways." Among other projects, VSN members will be involved in the content development of a chatbot to address common concerns the public has around issues related to vaccine safety.