PA Kache, S Cook, N Sizer, et al. The Lancet Planetary Health DOI:https://doi.org/10.1016/S2542-5196(21)00260-6
In response to COVID-19, international organizations (eg, World Health Organization) 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. 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 efforts ineffective. In addition, we cannot assume that pharmaceutical countermeasures, even if available, will have enough uptake to halt spread, given the institutional mistrust, vaccine hesitancy, and widespread misinformation that have become more prominent in society.
COVID-19 is at least the seventh pandemic to occur over the past century. To minimize 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. The global health sector is crucial to the implementation of solutions to prevent spillover that complement 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 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. The international community must support relevant countries in stopping deforestation through innovative solutions such as policy- and market-based incentives for keeping primary forests intact. 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. In addition, wildlife and livestock pathogen surveillance should be scaled up to manage and quickly contain outbreaks within animal populations before spillover to humans occurs. Finally, policies to ban or strictly regulate wildlife trade that poses a public health risk, but does not compromise the food security of local communities, should be formulated.
Comment: Failure to acknowledge solutions that target pathogen spillover reveals a global health injustice. It signals that the international community is tolerant of continued zoonotic outbreaks in low-income and low-resource settings as long as they do not become pandemics. Although preparedness and response are important to planning for future pandemics, governments must also commit to incorporating prevention of pathogen spillover to ensure equitable, integrated pandemic policies.