Since the first vaccine, health authorities have been challenged with responding to health-related events that, rightfully or wrongly, have been associated with vaccines. The current global controversies related to the HPV vaccine have posed extraordinary challenges to otherwise resilient national immunization programs. Highly publicized resistance to a vaccine against a killer cancer whose safety and effectiveness are backed up by an increasing volume of solid evidence,¹ once again confirms the need to bridge the risk perception gap between health authorities and the public. How can we best bridge this gap? The response must depend on the context, and many factors have been shown to play a role.

The particularity of this controversy is that it has evolved differently in countries that are geographically close and similar in many other respects. Challenges in countries with declining or low coverage include external factors such as vocal anti-HPV vaccine organizations; strong public anti-HPV vaccine advocates; and misinformed media responses (Figure 1). Internal factors that contributed in some countries included a lack of coordinated and rapid communication response; vaccine safety concerns among health workers; and a lack of support to young girls with unexplained symptoms in the first place, leading them to seek explanations on their own. In some countries, the vaccine was introduced by other public health programmes, such as sexual health or oncology, which have limited vaccine experience.

Reasons for the controversy are thus multifactorial, and so must the response be. Strategic communications and activities to build trust are critical elements, but certainly not the only ones. Organizational challenges, health worker scepticism and lack of coordination and strategic stakeholder and media relations need to be addressed as well.

Many national immunization programmes are now addressing these factors. Two best practice examples are Denmark and Ireland (box 1); as they rebuilt confidence after steep declines following successful introductions with acceptance at 90% and above (Figure 1). These countries responded with strategic and comprehensive efforts that are now producing positive results with more balanced public and media debates and indications of a reverse of the negative uptake trends (Figure 2).^2,3

Challenges are to some extent context-specific, and the response must be tailored to this (for example, some religious groups have specific concerns^4,5). At the same time, the nature of this controversy is also global, intensified by social media and regional collaboration between HPV-sceptic organizations. Sharing and working together across borders will also be critical for a successful response.

This has implications for the support needed. The WHO Regional Office for Europe has provided support to individual countries and also assisted countries to support each other where synergies exist. The Regional Office in 2016 established an HPV-peer group of immunization managers, who have bimonthly teleconferences and semiannual face-to-face meetings to share lessons learned and discuss the latest evidence on HPV. In addition, the Regional Office has developed materials, including a comprehensive HPV ‘questions and answers’ package for multiple target audiences, an online ‘Vaccination and trust’ library and guidance on respon ding to vocal vaccine deniers.⁶

Learning from the experiences of countries that have been struggling with internal and external challenges and acceptance of the HPV vaccine will be critical to ensure successful introductions of future new vaccines. Learning from others will also be important for the half of the world’s countries that still have not introduced the HPV vaccine; particular support will be needed for the countries that have weaker health systems, more vulnerable populations and less capacity to respond to vaccine safety-related crises. A concerted effort is needed, on the part of both countries and international organizations, to support these countries in being prepared, and building on the hard-earned lessons that have been learned.

References
1. Meeting report, Meeting of the Global Advisory Committee on Vaccine Safety, 7-8 June 2017. Available at: http:// apps.who.int/iris/bitstream/10665/255870/1/WER9228. pdf?ua=1 (Accessed 18 July 2018).
2. EPI-NYT (EPI-NEWS) 41/17, Danish State Serum Institute: https://www.ssi.dk/Aktuelt/Nyhedsbreve/EPI-NYT/2017/ Uge%2041%20-%202017.aspx(Accessed on 18 July 2018).
3. Personal communication: Preliminary data for 1st dose uptake 2017/18 in Ireland is 62%.
4. Bodson J, Wilson A, Warner EL, et al. Religion and HPV vaccine-related awareness, knowledge, and receipt among insured women aged 18-26 in Utah. PloS One 2017;12(8):e0183725.
5. Shelton RC, Snavely AC, De Jesus M, et al. HPV Vaccine Decision-Making and Acceptance: Does Religion Play a Role? J Relig Health 2013;52(4):1120-30. 6. WHO Regional Office for Europe resources. Available on website: http://www.euro.who.int/en/health-topics/ disease-prevention/vaccines-and-immunization/publications(Accessed on 18 July 2018).