COVID-19 is showing us the link between human and planetary health

This year marks the 50th anniversary of Earth Day, which was established in 1970 to highlight the need to protect our environment. Since then, our current geological era has been proposed as the Anthropocene, in recognition of the impact of human activities on the planet.

The concept of planetary health, meanwhile, highlights the fine balance between human health and the ecological disruptions that our societal structures engender - and it demonstrates that in addition to our impact on the planet, any disruption of the human-ecological balance has implications for our health, too.

The ongoing COVID-19 pandemic has animated this reality. While it is manifest as a health emergency, it could be more accurately framed as a planetary health emergency. That is because ongoing urban growth (two-thirds of the global population are expected to live in cities by 2050) has been associated with a disruption of the ecological balance, an increased risk of exposure to new pathogens and the emergence of new diseases.

When considering the health impact of new pathogens like COVID-19, it’s helpful to think about the characteristics of the host and the interaction between host and pathogen. The health of the human host before they are infected plays an important role in determining outcomes; in addition to older age, there is evidence of greater risk of a severe case of COVID-19 when there are co-morbidities such as obesity, heart disease, respiratory disease or diabetes.

The environment of the host, meanwhile, is a factor in their health - and, therefore, their vulnerability to COVID-19 - in several ways. Unequal access to safe housing increases exposure to indoor and outdoor air pollution and to damp conditions, which increase the risk of respiratory and heart disease. Inadequate access to affordable, nutritious food puts a healthy diet beyond the reach of significant portions of society in rich and poor countries alike, increasing the risk of obesity and diabetes.

In terms of transmission, a combination of the high-density living conditions in many in large urban centres worldwide and greater global interconnectedness will increase people's likelihood of coming into contact with the virus.

Infection control measures such as hand-washing will play an important role in ending this pandemic. However, unequal access to water and sanitation means the most vulnerable have a reduced capacity to perform this simple protective measure. Meanwhile, poor job security makes it difficult for many to stay home or practise physical distancing, which further exacerbates risk.

And for the unfortunate who do get sick, unequal access to healthcare - be that for disease management or access to a vaccine - further increases the likelihood of poor outcomes.

In summary, we have developed societies that disrupt ecology, increase vulnerability to disease, facilitate disease transmission, and in which many are unable to take necessary preventive precautions or to access care.

How is this not a crisis of civilisation?

The responses to the ongoing COVID-19 pandemic have demonstrated an unprecedented ability for all sectors of society to rally together. Why should this be, given the deficiencies we have shown in addressing the similarly existential emergency of climate change?

History has shown that collectively we find it easier to grasp the nature of an emergency when:

1. Cause and effect are side by side; for example, when exposure to the new coronavirus is directly and visibly linked to symptoms consistent with COVID-19. Any disconnect either in time (if it took three years to get sick, for example) or space (if, say, exposure in London resulted in deaths in Lagos) appears to impact our comprehension, risk perception and sense of urgency.

2. It is impossible to go about normal daily life either because of measures to address the emergency or the emergency itself.

3. The consequences cannot be “othered” as it affects all sections of society, not just particular groups.

In addition, calls for action to address an emergency are more likely to generate a response when:

1. The ask is clear and finite.

2. Action does not require structural long-term change.

3. The beneficial effect of the action can be attributed to the responder.

The combination of this dissonance in our perception of emergency and the factors that influence how we respond have implications for our motivation, urgency and our choice of action.

What if we could activate our social imagination to think differently about our health systems? What if we addressed the social determinants of health, cognisant of the natural systems on which we depend? Our responses to COVID-19 have demonstrated that inter-sectoral collaboration is possible, that global cooperation is necessary for wicked problems, and that extraordinary efforts to communicate and engage all levels of society are possible.

What if we also thought differently about emergencies with a greater focus on foresight, cognisant of our perception bias?

This would require that we grapple with complex and evolving realities and environments that increase the risk of new diseases emerging and that accelerate climate change. It would also require recognition of the evolving roles that we can and should play. Lastly, it would require a systems-based approaches to prevention in order to reduce the risk of emergencies and (if they occur) to prevent disasters.

The core principles of such an approach would include:

1. The need for clear global leadership, highlighting the importance of organisations like the WHO.

2. Recognition of the need for various urban sectors such as transportation, energy and housing to work together to improve health outcomes in cities.

3. Risk sharing, with stakeholders who invest in and benefit from cross-sectoral collaboration also sharing costs.

4. Innovative strategies to incorporate health and environmental impacts into performance indicators in both the public and private sectors.

5. A focus on both the curative and preventive aspects of healthcare.

An imaginative approach to addressing the planetary health emergencies we face would include strategies to:

1. Flatten the curve of healthcare need. Lowering the baseline need for healthcare by reducing inequality would serve to make populations more resilient to emergencies, as well as enabling humanitarian and emergency services to respond more effectively during health and/or environmental crises.

2. Vaccinate all of society by providing the natural and built environments necessary to protect health and avoid ecological disruption, and achieve 'herd immunity' by addressing the social determinants of health, thereby reducing people's vulnerability to ill health.

3. Supplement epidemiological models with value models based on our shared purpose. While it would be naïve not to acknowledge the varying and divergent views on societal goals around the world, the shared global experience of the COVID-19 pandemic has perhaps suggested a common starting point: a world in which emergencies that disrupt societal functioning, such as pandemics, are not an everyday reality.

The planetary pause we are experiencing on the 50th anniversary of Earth Day should be used to re-assess our purpose. In so doing, we quickly realise that we cannot address this or any future health or environmental emergencies without addressing their social, economic and political determinants; our response cannot be restricted to any one sector but must instead take a whole-of-society approach; and we must recognise it is short sighted to focus on health to the detriment of ecological boundaries.

We need to consider the interconnected systems that influence planetary health and the balance between human and ecological wellbeing, as we set about the slow work of repurposing the building blocks of society i order to address the socio-ecological determinants of health and to build a more sustainable future.