The health and economic impacts from infectious disease emergence are substantial. 1 Bernstein AS Ando AW Loch-Temzelides T et al. The costs and benefits of primary prevention of zoonotic pandemics. Sci Adv. 2022; 8eabl4183 Crossref Scopus (89) Google Scholar Pathogens that are transmitted, or spill over, between animals and people are the source of most emerging infectious diseases in humans. 2 Jones KE Patel NG Levy MA et al. Global trends in emerging infectious diseases. Nature. 2008; 451: 990-993 Crossref PubMed Scopus (5197) Google Scholar Indeed, spillovers sparked five viral pandemics from 1918 through to 2009 (1918 influenza, 1957–58 influenza, 1968 influenza, 2009 influenza, and HIV), and peer-reviewed evidence strongly suggests that COVID-19 was the result of spillovers too. 3 US Centers for Disease Control and PreventionPast pandemics. https://www.cdc.gov/flu/pandemic-resources/basics/past-pandemics.htmlDate accessed: August 7, 2023 Google Scholar , 4 Worobey M Han G-Z Rambaut A Genesis and pathogenesis of the 1918 pandemic H1N1 influenza A virus. Proc Natl Acad Sci USA. 2014; 111: 8107-8112 Crossref PubMed Scopus (170) Google Scholar , 5 Kawaoka Y Krauss S Webster RG Avian-to-human transmission of the PB1 gene of influenza A viruses in the 1957 and 1968 pandemics. J Virol. 1989; 63: 4603-4608 Crossref PubMed Scopus (0) Google Scholar , 6 Mena I Nelson MI Quezada-Monroy F et al. Origins of the 2009 H1N1 influenza pandemic in swine in Mexico. eLife. 2016; 5e16777 Crossref Scopus (201) Google Scholar , 7 Sharp PM Hahn BH Origins of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med. 2011; 1a006841 Crossref PubMed Scopus (819) Google Scholar , 8 Pekar JE Magee A Parker E et al. The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2. Science. 2022; 377: 960-966 Crossref PubMed Scopus (93) Google Scholar , 9 Worobey M Levy JI Malpica Serrano L et al. The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic. Science. 2022; 377: 951-959 Crossref PubMed Scopus (149) Google Scholar Spillovers are a reminder that humans are inherently part of nature and that human wellbeing is intertwined with that of animals and the environment. As such, adopting a One Health approach when addressing viral pandemic threats is imperative. 10 Keusch GT Amuasi JH Anderson DE et al. Pandemic origins and a One Health approach to preparedness and prevention: solutions based on SARS-CoV-2 and other RNA viruses. Proc Natl Acad Sci USA. 2022; 119e2202871119 Crossref PubMed Scopus (38) Google Scholar

The pathogens that cause most emerging infectious diseases in humans originate in animals, particularly wildlife, and then spill over into humans. The accelerat-ing frequency with which humans and domestic animals encounter wildlife because of activities such as land-use change, animal husbandry, and markets and trade in live wildlife has created growing opportunities for patho-gen spillover. The risk of pathogen spillover and early disease spread among domestic animals and humans, however, can be reduced by stopping the clearing and degradation of tropical and subtropical forests, improv-ing health and economic security of communities liv-ing in emerging infectious disease hotspots, enhancing biosecurity in animal husbandry, shutting down or strictly regulating wildlife markets and trade, and expanding pathogen surveillance. We summarize expert opinions on how to implement these goals to prevent outbreaks, epidemics, and pandemics.

In response to COVID-19, international organisations (eg, WHO and G20) have convened multiple expert panels tasked with objectives such as assessing what happened during COVID-19, why it happened, and how it can be prevented from happening again.1The Independent Panel for Pandemic Preparedness & ResponseCOVID-19: make it the last pandemic.https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdfDate: 2021Date accessed: July 28, 2021Google Scholar, 2G20 High Level Independent PanelA global deal for our pandemic age.https://www.g20.org/wp-content/uploads/2021/07/G20-HLIP-Report.pdfDate: 2021Date accessed: August 2, 2021Google Scholar Unfortunately, these panels have failed to develop comprehensive strategies that address the source of most emerging infectious diseases: spillover of pathogens from animals to people. Instead, expert panels have focused on preparing for and responding to pathogens after they have emerged in human populations. Although these policies are crucial, they only address part of the solution. Pandemic preparedness and response alone are insufficient, partly because it is difficult to predict infectious disease dynamics before spillover. The urban transmission of Ebola virus, sexual transmission of Zika virus, and airborne transmission of SARS-CoV-2 all highlight that emerging infectious diseases can have characteristics that defy conventional clinical and epidemiological expectations. Similarly, it is possible that a future novel pathogen will have attributes (eg, a long pre-symptomatic transmission period) that render even the best public health response efforts ineffective. Furthermore, we cannot assume that pharmaceutical countermeasures, even if available, will have enough uptake to halt spread, given the institutional mistrust, vaccine wariness, and misinformation that have become more prominent in society. COVID-19 is at least the seventh pandemic to occur over the past century.3Cucinotta D Vanelli M WHO declares COVID-19 a pandemic.Acta Biomed. 2020; 91: 157-160PubMed Google Scholar, 4LeDuc JW Barry MA SARS, the first pandemic of the 21st century.Emerg Infect Dis. 2004; 10: e26Crossref Google Scholar, 5Sharp PM Hahn BH Origins of HIV and the AIDS pandemic.Cold Spring Harb Perspect Med. 2011; 1a006841Crossref PubMed Scopus (772) Google Scholar, 6Centers for Disease Control and PreventionPast pandemics.https://www.cdc.gov/flu/pandemic-resources/basics/past-pandemics.htmlDate: Aug 10, 2018Date accessed: August 3, 2021Google Scholar To minimise the risk of future pandemics, pathogen spillover must be prevented along with pandemic preparedness and response. The risk for pathogen spillover is on the rise because of increased human and domestic animal interactions with wildlife related to deforestation, animal husbandry, and wildlife trade.7Allen T Murray KA Zambrana-Torrelio C et al.Global hotspots and correlates of emerging zoonotic diseases.Nat Commun. 2017; 81124Crossref PubMed Scopus (509) Google Scholar The global health sector is crucial to the implementation of solutions to prevent spillover that complement existing efforts to prepare for an outbreak. Among these solutions are policies aimed at stopping deforestation, improving community health in emerging infectious disease hotspots, improving livestock management and surveillance, and banning or strictly regulating wildlife trade that poses a public health risk. Deforestation brings susceptible people into forest environments, where they come into contact with wildlife and disease vectors (eg, mosquitoes) during logging, hunting, and other activities.8Wolfe ND Daszak P Kilpatrick AM Burke DS Bushmeat hunting, deforestation, and prediction of zoonoses emergence.Emerg Infect Dis. 2005; 11: 1822-1827Crossref PubMed Scopus (413) Google Scholar The international community must support relevant countries in stopping deforestation through innovative solutions such as policy-based and market-based incentives for keeping primary forests intact.9Nepstad D McGrath D Stickler C et al.Slowing Amazon deforestation through public policy and interventions in beef and soy supply chains.Science. 2014; 344: 1118-1123Crossref PubMed Scopus (686) Google Scholar In regions where forests have been heavily cleared or degraded and spillover risk is already high (eg, in West Africa and southeast Asia), community health must be strengthened. Additionally, wildlife and livestock pathogen surveillance should be scaled-up to manage and quickly contain outbreaks within animal populations before spillover to humans occurs. Finally, the health sector is uniquely positioned to engage in policy formulation to ban or strictly regulate wildlife trade that poses a public health risk but does not compromise the food security of local communities. Unfortunately, this type of forward thinking, multisectoral prevention has been almost entirely overlooked by the expert panels. For instance, in May, 2021, the WHO-commissioned Independent Panel for Pandemic Preparedness and Response (IPPPR) released a report titled, COVID-19: Make it the Last Pandemic.1The Independent Panel for Pandemic Preparedness & ResponseCOVID-19: make it the last pandemic.https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdfDate: 2021Date accessed: July 28, 2021Google Scholar The IPPPR provided thorough recommendations on preparedness and response and acknowledged that most emerging pathogens are zoonotic in origin; however, it failed to provide concrete strategies for spillover prevention. This omission could have been expected, given that the IPPPR's objective was to "[prepare] the world…so that the next disease outbreak does not become a pandemic."1The Independent Panel for Pandemic Preparedness & ResponseCOVID-19: make it the last pandemic.https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdfDate: 2021Date accessed: July 28, 2021Google Scholar The scope of this objective does little to address the mechanisms for how pathogens emerge in human populations.7Allen T Murray KA Zambrana-Torrelio C et al.Global hotspots and correlates of emerging zoonotic diseases.Nat Commun. 2017; 81124Crossref PubMed Scopus (509) Google Scholar Failure to acknowledge solutions that target pathogen spillover also reveals a disquieting global health injustice. It signals that the international community is tolerant of continued zoonotic outbreaks in low-income and low-resource settings so long as they do not become pandemics. In July, 2021, the G20 High Level Independent Panel (HLIP) released a report proposing the organisation of global finances to address future pandemics.2G20 High Level Independent PanelA global deal for our pandemic age.https://www.g20.org/wp-content/uploads/2021/07/G20-HLIP-Report.pdfDate: 2021Date accessed: August 2, 2021Google Scholar The HLIP's report discussed habitat loss and livestock management as components of prevention requiring greater attention. However, the HLIP excluded a complete One Health approach in their investment calculations because "it would have been difficult to provide comprehensive and up-to-date estimates."2G20 High Level Independent PanelA global deal for our pandemic age.https://www.g20.org/wp-content/uploads/2021/07/G20-HLIP-Report.pdfDate: 2021Date accessed: August 2, 2021Google Scholar The intentionality of omitting these costs is underscored by the fact that they had been shared by experts engaging with the HLIP but were still excluded.10Coalition to Prevent Pandemics at the SourceToward a comprehensive financial architecture to enable pandemic prevention.https://72d37324-5089-459c-8f70-271d19427cf2.filesusr.com/ugd/518e5d_76d8fdc18ca94b9b85fb09a6c54bf099.pdfDate: April 30, 2021Date accessed: August 2, 2021Google Scholar By keeping One Health costs ill-defined and deeming this investment as out of scope, the HLIP abandoned a core public health principle: engaging in primary prevention by addressing upstream drivers of pandemics. The unfortunate reality is that spillover prevention costs of approximately US$10 billion pale in comparison with the millions of lives and trillions of dollars that it has cost to respond to COVID-19.10Coalition to Prevent Pandemics at the SourceToward a comprehensive financial architecture to enable pandemic prevention.https://72d37324-5089-459c-8f70-271d19427cf2.filesusr.com/ugd/518e5d_76d8fdc18ca94b9b85fb09a6c54bf099.pdfDate: April 30, 2021Date accessed: August 2, 2021Google Scholar The IPPPR called for a transformation of global systems on 18 occasions in their 86-page report.1The Independent Panel for Pandemic Preparedness & ResponseCOVID-19: make it the last pandemic.https://theindependentpanel.org/wp-content/uploads/2021/05/COVID-19-Make-it-the-Last-Pandemic_final.pdfDate: 2021Date accessed: July 28, 2021Google Scholar True transformational change requires looking beyond traditional disciplines that constrain our ability to solve intersecting systems issues. Preparedness and response are undoubtedly important to planning for future pandemics. However, they are only part of the solution; governments must also commit to incorporating prevention of pathogen spillover to ensure equitable, integrated pandemic policies. We declare no competing interests.