Immunization: Vital Progress, Unfinished Agenda

"Immunization is one of the best investments in health and should remain a priority for research, industry, public health and society."

This paper is a response to, and call for action to address, the fact that vaccine-preventable diseases (VPDs) such as measles are on the rise, and episodes of vaccine reluctance and refusal are occurring globally. The authors discuss: the current status of vaccine coverage, as well as unmet needs, hurdles to overcome to ensure sustainable immunisation programmes (starting with the discovery of a new vaccine), the growing issue of vaccine confidence, and opportunities and needed actions to ensure the full potential of immunisation for human health and society. The below summary focuses on the communication-centred elements of the analysis.

Opening sections of the paper explore how immunisation has prevented millions of deaths, diseases, and disabilities, explaining concepts like herd immunity and noting that, beyond health, there are economic, educational, health security, and other benefits. The authors stress that, in addition to being "the backbone of maternal and child health, vaccines provide important health benefits for all stages in life" - this, despite the fact that "[a]dult immunization does not have a clear prioritization in low- and middle-income countries, and is a complex programme across high-income countries." But, they note, the demographics are shifting across the world to an older distribution; thus, as the World Coalition on Adult Vaccination has advocated, a focus on adult immunisation will become increasingly relevant.

The authors observe that, "[u]nlike therapeutics, vaccines are used in healthy people, and demand a very high standard of safety and require continuous monitoring for potential side effects. Besides considerations of safety, effectiveness, impact and cost, this raises complex governance, regulatory and public trust issues." These issues are particularly salient in the case of the long and complex process required for the development and deployment of new vaccines. The authors describe 4 hurdles that need to be overcome from the discovery phase of a new vaccine to sustainable population impact. For example, there are challenges with the development of vaccines against epidemic pathogens; in this case, well-informed country leadership and transparent governance of such is described here as crucial, as is genuine community involvement. Even after the lengthy and costly trajectory to introduce a new vaccine, there can be issues related, among others, to demand sustainability, acceptance of immunisation, and equity of access.

The paper examines various unmet needs for vaccination, noting that, although some countries have achieved substantial improvements in coverage, it is declining in others, often due to social disruption, conflict, or political upheaval. For instance, the measles outbreaks that are occurring in all regions of the world are a result of a mixture of vaccine refusals, cultural beliefs, access issues, and political and economic crises.

As reported here, approximately 60% of all children who did not receive basic immunisation in 2018 live in 10 countries: Angola, Brazil, the Democratic Republic of the Congo (DRC), Ethiopia, India, Indonesia, Nigeria, Pakistan, the Philippines, and Vietnam. The WHO offers guidance on implementing high-impact immunisation programmes (Global Routine Immunization Strategies and Practices, GRISP) to address some of these unmet needs. But, in addition to support by international organisations, achieving rapid change in this situation will require the full commitment of governments and local political commitment, the authors stress. As demand for services from communities increases, governments (who are often the funder of these services) need to respond accordingly.

Next, the authors articulate what they call the "equity imperative", writing: "To reach those who are in greatest need means addressing issues of vaccine availability, affordability, accessibility, acceptability and financing. An effective immunization system that delivers vaccines with high equity across social and ethnic strata, maternal and community education, and geographies, is a purpose-built programme to deliver impact, and has been shown to be the crucial programmatic target."

Relatedly, the issues that arise in conflict and humanitarian/crisis settings represent a serious impediment to immunisation. For instance, "[t]he persisting hurdles to the eradication of polio reveal how political, social and conflict situations can disrupt access to populations and risk violence targeting vaccinators such as in Pakistan and Afghanistan..." As is explained here, conflict situations also affect confidence in vaccines and vaccinators due to an environment of distrust and uncertainty, such as in the DRC, where local violence and conflict in the Ebola-affected areas has been an obstacle to vaccination efforts.

In fact, the growing challenge of vaccine confidence is worrisome to these authors, and they examine the communication-specific and other issues surrounding vaccine hesitancy. Some of the newer challenges to vaccine confidence include social media campaigns that have disrupted measles, mumps, and rubella (MMR) vaccination efforts in southern India, defeated human papillamovirus (HPV) vaccination efforts in Japan, provoked false scares of vaccine poisoning in Pakistan, and undermined vaccination programmes in Indonesia. "In addition, the misuse of vaccination campaigns as political tools has seriously damaged vaccine confidence in areas such as the Philippines, Nigeria, Afghanistan, Italy and Pakistan."

They take a closer look at the communication-related challenges associated with the introduction of new vaccines, which "requires adequate time to train and prepare front-line health workers and vaccinators to be ready to manage public questions, and continuing dialogue between scientists and the public will be important to build confidence from the start, as well as to anticipate and manage adverse events." As a specific illustration, they examine the 2018 dengue vaccine controversy in the Philippines. Some side effects or limitations of duration of protection may only become obvious after larger-scale use; in the Philippines, this new risk was reported only after more than 800,000 school children were vaccinated, prompting a marked reaction by the public. Reported risks of the recently introduced vaccine were amplified into public outrage mediated through Facebook pages - a situation made more complex because the events occurred during political elections. The result was a marked drop in public confidence in vaccines more generally from 99.5% in 2015 to 76.2% in 2018 in that country.

In light of such experiences, the authors suggest, for example, that: "What needs to be addressed is not only better communication around the known, albeit sometimes misinterpreted, risks and benefits of vaccination, but also investing in more research in the areas in which the public is asking questions and the science is incomplete....New modes of listening to the public, with rapidly evolving technologies to monitor social media, can collect emerging safety questions as well as detect signals of possible issues that need investigation. Working towards better aligned public questions and accessible, evidence-based answers should be a goal."

They also observe that "[i]nclusion of non-traditional partners, new modes of digital communication, social scientists, and religious and traditional leaders have been invaluable in addressing hesitancy around polio vaccination, and the engagement of teenage girls in co-designing social media outreach to address HPV vaccination concerns had positive effects on vaccine uptake in Denmark. With safety anxieties being reported as one of the top reasons for vaccine hesitancy, aligning vaccine safety research with dominant safety concerns will also be important for confidence building."

The paper concludes with some overall recommendations for optimising the effect of vaccination:

1. Stronger political leadership and funding, both domestically and internationally;
2. Universal vaccine coverage and equity, with a focus on ensuring that vulnerable people in all countries are not left behind;
3. People-centred programmes that take into account local variation in immunisation levels, specific needs, cultural specifics, and circumstances of vulnerable populations;
4. Efforts to address vaccine confidence up front that eschew older demand-creation models and instead engage with the public, building on local capacities and starting with better listening and prompt response to concerns; and
5. Increased investment in research and innovation.