Communicating uncertainty during public health emergency events: a systematic review

To answer the question, "What are the best ways to communicate uncertainties to public audiences, at-risk communities, and stakeholders during public health emergency events?" we conducted a systematic review of published studies, grey literature, and media reports in English and other United Nations (UN) languages: Arabic, Chinese, French, Russian, and Spanish. Almost 11,500 titles and abstracts were scanned of which 46 data-based primary studies were selected, which were classified into four methodological streams: Quantitative-comparison groups; Quantitative-descriptive survey; Qualitative; and Mixed-method and case-study. Study characteristics (study method, country, emergency type, emergency phase, at-risk population) and study findings (in narrative form) were extracted from individual studies. The findings were synthesized within methodological streams and evaluated for certainty and confidence. These within-method findings were next synthesized across methodological streams to develop an overarching synthesis of findings. The findings showed that country coverage focused on high and middle-income countries in Asia, Europe, North America, and Oceania, and the event most covered was infectious disease followed by flood and earthquake. The findings also showed that uncertainty during public health emergency events is a multi-faceted concept with multiple components (e.g., event occurrence, personal and family safety, recovery efforts). There is universal agreement, with some exceptions, that communication to the public should include explicit information about event uncertainties, and this information must be consistent and presented in an easy to understand format. Additionally, uncertainty related to events requires a distinction between uncertainty information and uncertainty experience. At-risk populations experience event uncertainty in the context of many other uncertainties they are already experiencing in their lives due to poverty. Experts, policymakers, healthcare workers, and other stakeholders experience event uncertainty and misunderstand some uncertainty information (e.g., event probabilities) similar to the public. Media professionals provide event coverage under conditions of contradictory and inconsistent event information that can heighten uncertainty experience for all.