COVID-19 and Preventing Future Pandemics

By focusing attention on only post-spillover outbreak and pandemic preparedness, policymakers are missing the most cost effective and equitable solution to pandemic prevention—stopping spillover at the source. Banner image: Shutterstock/Lizavetta

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This article is part of a series in which OECD experts and thought leaders  from around the world and all parts of society  address the COVID-19 crisis, discussing and developing solutions now and for the future. Aiming to foster the fruitful exchange of expertise and perspectives across fields to help us rise to this critical challenge, opinions expressed do not necessarily represent the views of the OECD.

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Almost all pandemics are caused by viruses that spillover from wildlife into humans, a process known as zoonosis. Most new and emerging diseases (most of which fortunately do not reach the scale of pandemics) are zoonotic in origin. Examples include all influenzas, Ebola, Zika, HIV/AIDS, MERS, SARS and, almost certainly, COVID-19. 

The rate of emergence of new infectious diseases has also increased significantly in recent decades. This correlates with increased human contact with wildlife, especially in tropical regions. Expanding agriculture, road building, mining, logging and the often-associated increase in commercial-scale hunting and trade in live animals all greatly increase the risk of human exposure to novel viruses.

Find more on Forum Network: Spillover: Animal Infections and the Next Human Pandemic, by

Find more on Forum Network: Spillover: Animal Infections and the Next Human Pandemic, by David Quammen

High-level, global processes are developing policy prescriptions and commitments with governments aimed at preventing and preparing for future pandemics. There is a broad understanding that COVID-19 was predicted by many scientists and could potentially have been avoided had governments been better prepared. The G7, G20, WHO and various panels and commissions have developed recommendations to learn from the mistakes at the start of the COVID-19 outbreak. These recommendations focus on important post-spillover actions that can help to limit the spread of a new outbreak once it has occurred. Substantial investment is proposed, for example, in expanding the capacity in the Global South to manufacture and distribute vaccines. 

But by focusing attention on only post-spillover outbreak and pandemic preparedness, policymakers are missing the most cost effective and equitable solution to pandemic prevention—stopping spillover at the source. A comprehensive approach should include both pre- and post-spillover interventions.

Despite the unprecedented speed with which highly effective vaccines were developed against COVID-19, their distribution and access to effective treatments have been highly inequitable. Currently only 3% of people living in least developed countries have received even one COVID-19 vaccine does. There is no doubt that the impact of COVID-19 has been felt disproportionately by the poor and underprivileged.

Future outbreaks could involve longer incubation periods, be deadlier, or be much harder to develop vaccines against. COVID-19 has resulted in an estimated 20 million deaths worldwide—but the next pandemic could be much worse.

The United States and Europe have spent around USD 10 trillion maintaining economic stability and supporting businesses and individuals impacted by pandemic lockdowns. The IMF estimates that the global economic cost of the pandemic is approaching USD 30 trillion.

A team of leading scientists and economists estimated that by comparison, a far smaller, forward-looking investment of USD 10-20 billion annually would substantially reduce spillover risk, reducing the danger of new disease outbreaks becoming pandemics.

According to an independent scientific taskforce convened by the Harvard T.H. Chan School of Public Health, specific interventions that would help to reduce spillover risk if scaled up, especially across tropical and subtropical regions, are fourfold:

  • Conserve tropical forests, especially those relatively intact but also those that have been fragmented
  • Improve biosecurity for livestock and farmed wild animals, especially when animal husbandry occurs near large or rapidly expanding human populations
  • Establish an intergovernmental partnership to address spillover risk from wild animals to livestock and people, made up of aligned organisations such as FAO, WHO, OIE, UNEP and Wildlife Enforcement Networks
  • In low- and middle-income countries, leverage investments to strengthen healthcare systems and One Health platforms to jointly advance conservation, animal and human health and spillover prevention

The Preventing Pandemics at the Source coalition, a group of leading health rights, public health and environmental groups, came together to advocate for a comprehensive approach to preventing future pandemics. This approach should recognise that relatively low-cost interventions to reduce the risk of zoonotic spillover, as summarised above, should become integral to public health policy and spending, consistent with One Health thinking. Not doing so ignores good science and prudent economics.

Find out more about the Preventing Pandemics at the Source coalition

Find out more about the Preventing Pandemics at the Source coalition

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Tackling COVID-19 Health Climate

Nigel Sizer

Executive Director, Preventing Pandemics at the Source

Nigel Sizer serves as the executive director of the Preventing Pandemics at the Source initiative with Dalberg Catalyst. Concurrently, he is also, Chief Global Alliances Officer with the Rainforest Alliance.  He served for two years as president of Rainforest Alliance until January 2018. He helped lead the successful merger with the leading Dutch-based non-profit UTZ and following the merger he served as Chief Program officer.

Previously, as global director of the Forests Program at the World Resources Institute, Sizer led a hundred-person team across Africa, Asia, and Latin America and launched path-breaking partnerships including the award-winning Global Forest Watch and the Global Restoration Initiative.Sizer also served as vice president for Asia-Pacific with Rare, where he developed grassroots efforts to link impoverished communities in Indonesia to global carbon markets and pioneered community-based fisheries and marine protected areas efforts. In 2008, he served as lead advisor on climate change and energy issues in Asia to former US President Bill Clinton and the Clinton Global Initiative. He has also worked with the United Nations Environment Program (UNEP) in Nairobi and established The Nature Conservancy’s Asia-Pacific Forest Program. He also founded and co-chaired The Forests Dialogue, which recently celebrated 20 years of progress, and helped establish and lead the Asia Forest Partnership.

A globally recognized authority on forests, ecology, climate change and development policy, Sizer holds Bachelors, Masters, and Doctoral degrees in natural sciences and tropical forest ecology from the University of Cambridge. He has lived and worked in Brazil, Kenya, and spent ten years in Indonesia. He has served on numerous boards and advisory groups including Natural State, Tree Global, the Tropical Forest Alliance, the Rainforest Foundation, the Amazon Alliance, the Global Forest Foundation, and the Andean Center for Sustainable Development. He has received numerous awards including the Henry Arnold Conservation Fellowship from the Mulago Foundation and the United Nations Secretary General’s Big Data Challenge prize.