Feasibility, Acceptability, and Effectiveness of Non-Pharmaceutical Interventions for Infectious Disease Prevention and Control in Crisis-Affected Settings and Informal Settlements: A Scoping Review
Authors: Polonsky Jonathan A. , Bhatia Sangeeta , Fraser Keith , Hamlet Arran , Skarp Janetta , Stopard Isaac J. , Hugonnet Stéphane , Kaiser Laurent , Lengeler Christian , Blanchet Karl , Spiegel Paul 
Published: August 2021

Introduction

Non-pharmaceutical interventions (NPIs) are a crucial suite of measures to prevent and control infectious disease outbreaks. They are particularly important for crisis-affected populations that typically reside in settings characterised by overcrowding, inadequate access to healthcare and resource limitations. To describe the landscape of research and identify evidence gaps concerning the acceptability, feasibility, and effectiveness of NPIs among crisis-affected populations and informal settings, we conducted a systematic scoping review of the published evidence.

Methods

We systematically reviewed peer-reviewed articles published between 1970 and 2020 to collate available evidence on the feasibility, acceptability, and effectiveness of NPIs in crisis-affected populations and informal settlements. We performed quality assessments of each study using a standardised questionnaire.

Results

Our review included 158 studies published in 85 peer-reviewed articles. Most research used low quality study designs. The acceptability, feasibility, and effectiveness of NPIs was highly context dependent. In general, simple and cost-effective interventions such as community-level environmental cleaning and provision of water, sanitation and hygiene services, and distribution of items for personal protection such as insecticide-treated nets, were both highly feasible and acceptable. Logistical, financial, and human resource constraints affected both the implementation and sustainability of measures. Community engagement emerged as a strong factor contributing to the effectiveness of NPIs. Conversely, measures that involve potential restriction on personal liberty such as case isolation were found to be less acceptable to the community.

Conclusion

Overall, the evidence base was patchy, with substantial knowledge gaps between differing between settings and pathogens. Although implementation of NPIs presents unique practical challenges, it is critical that the lessons learned are shared with the wider community to build a robust evidence base.

Summary box

What is already known?

- NPIs are a crucial suite of tools for the prevention and control of infectious diseases, either as a complement to, or in the absence of, effective pharmaceutical interventions (i.e., therapeutics and vaccination).

- Despite being disproportionately vulnerable, crisis-affected populations and those living in informal settlements are often neglected by research and guidance. NPIs are, however, vital and adaptation is necessary within these settings due to poor living conditions and resource limitations that intensify disease transmission risk.

What are the new findings?

- We conducted a scoping review to produce a landscape analysis of the existing evidence concerning NPIs within crisis-affected settings and informal settlements.

- The existing evidence is patchy, uneven, occasionally contradictory, and of generally low quality, but building over time.

- Although limited, some findings are generalisable across settings, populations and NPIs.

What do the new findings imply?

- There is a need for greater investments in research to strengthen the guidance and policies on NPIs in these settings.

- In particular, upstream pilot feasibility and acceptability studies should be conducted prior to the widespread roll-out of interventions to ensure they are feasible, acceptable, and ultimately effective for the target populations.