Blog: All for One Health and Health Impact Assessment

In this blog, Ben Cave and Joanna Purdy discuss recent developments from Ireland and Northern Ireland in Health Impact Assessment (HIA). They discuss their role in the Institute of Public Health’s new HIA guidance, they ask how can HIA help adapting to and recovering from COVID-19 and how it links with the broader One Health agenda. 

Joanna Purdy is Public Health Development Officer at the Institute of Public Health and Ben Cave is a director of BCA Insight (Ireland) and the current president of the International Association for Impact Assessment.


What is HIA?

HIA provides a structured way for legislation, policies, programmes and projects to be scrutinised for their effects on public health. It is multisectoral and is part of Health in All Policies. The key point about HIA is that it should not stop at scrutiny. It is done while writing the legislation or developing policy and it identifies changes needed to strengthen the protection and promotion of health and to improve equity in health.

What is One Health?

The ‘One Health’ approach addresses health threats in the animal, human and environment interface [1]. Like HIA, it is an approach to designing and implementing programmes, policies, legislation and research in which multiple sectors communicate and work together to achieve better public health outcomes.

What’s happening with HIA on the island of Ireland ?

We consulted key stakeholders across the island of Ireland as we wrote this guidance. Healthy Ireland [2] and Making Life Better [3] frame public health in the Republic of Ireland and in Northern Ireland, respectively and they each place a high priority on improving health and on tackling the wider determinants of health. They are also clear about the importance of Health in All Policies, equity and social justice and HIA.

What does this new HIA guidance bring?

The guidance sets out the rationale for HIA and it provides some conceptual models. It looks at how to conduct a standalone HIA. It is completely multisectoral, so it also looks at health in environmental assessment which is an umbrella term for Strategic Environmental Assessment (SEA), which is applied at the strategic level, as the name suggests, and for Environmental Impact Assessment (EIA) which is applied to projects. The guidance builds on work across Europe for health in environmental assessment [4,5] to show how health can be considered in these assessment.

It comes in a suite of documents for the different audiences and users of HIA. The guidance uses 30 case studies to show practice from across the island of Ireland, the UK and internationally. It shows how HIA has been used on a wide range of policy and planning matters as well as matters related to pandemic recovery – see also the recent RTÉ Brainstorm on HIA [6].


What role can HIA have in the One Health agenda?

That’s a really good question and one to keep an eye on. One Health is rising up the agenda as we tackle this pandemic. Partnerships between public health, animal and environmental sciences will become increasingly important but there can be challenges working across sectors [7].

What about impact assessment and One Health? The Pan-European Commission on Health and Sustainable Development recently stressed the importance of One Health and called for impact assessment to be used in rethinking policy priorities [8].

The new IPH guide uses the definition of health from the 1946 WHO constitution which is a long-established source [9] and which can incorporate One Health. The IPH guidance is not just focused on One Health, but it can certainly incorporate it as it allows all determinants of health to be considered appropriately. And to do a good HIA you need to work across sectors and this guide will certainly help with that.

The launch of the IPH guidance on HIA will be later this year and it will accompanied by a programme of capacity building across the island of Ireland.


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1. World Health Organization. One Health. 2021.

2. Department of Health. Healthy Ireland Framework. A framework for improved health and wellbeing 2013-2025. Government of Ireland.  2013.

3. Department of Health. Making Life Better. A whole system strategic framework for public health. 2013-2023. Northern Ireland Executive.  2014.

4. United Nations Economic Commission for Europe. Draft guidance on assessing health impacts in strategic environmental assessment. Geneva: UNECE.  2020.

5. Cave B, et al. Human health: ensuring a high level of protection. A reference paper on addressing Human Health in Environmental Impact Assessment as per EU Directive 2011/92/EU amended by 2014/52/EU. International Association for Impact Assessment and European Public Health Association.  2020.

6. O’Mullane M, Cave B. What could we learn from a health impact assessment of Covid-19? 2021.

7. Enserink M. Infectious diseases. Humans, animals–it’s one health. Or is it? Science 2010; 327(5963): 266-7.

8. Pan-European Commission on Health and Sustainable Development. Rethinking policy priorities in the light of pandemics: a call to action. Copenhagen, Denmark, World Health Organization Regional Office for Europe.  2021.

9. World Health Organization. Constitution. Geneva: World Health Organization.  1946.

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