Zoonotic diseases can kill at least 3.3 mn people each year, says Harvard study

 

At least 3.3 million people are expected to die each year from viral zoonotic diseases transmitting from animals to humans, with the estimated value of lives lost pegged at a minimum $350 billion, along with additional economic losses of $212 billion, says a study done by Harvard T.H. Chan School of Public Health.

The study published in Science Advances, a peer reviewed journal, noted that two years after COVID-19 emerged, researchers have provided three cost-effective actions to help decision-makers prevent future pandemics by stopping “spillover” of diseases from animals into humans: better surveillance of pathogens, better management of wildlife trade and hunting, and reduced deforestation.  

 

The annual costs of these “primary pandemic prevention” actions (~$20 billion) are less than 5 per cent of the lowest estimated value of lives lost from emerging infectious diseases every year, less than 10 per cent of the economic costs, and provide substantial co-benefits, the study has indicated.  

 

“If COVID-19 taught us anything, it is that testing, treatments, and vaccines can prevent deaths but they do not stop the spread of viruses across the globe and may never prevent the emergence of new pathogens. As we look to the future, we absolutely cannot rely on post-spillover strategies alone to protect us,” said Dr Aaron Bernstein, director of the Center for Climate, Health, and the Global Environment at Harvard T.H. Chan School of Public Health.   

“Spending only five cents on the dollar can help prevent the next tsunami of lives lost to pandemics by taking cost-effective actions that stop the wave from ever emerging, instead of paying trillions to pick up the pieces,” Bernstein added.  

 

Authors took Spanish influenza 1918 into consideration, a pandemic which caused over 50,000,000 deaths (27,322 death per million). The authors have identified India has a high-risk country for pandemics.  

 

With the baseline expected annual mortality from viral disease epidemics with the current world population of 3.3 million lives, the researchers said, estimated willingness to pay (WTP) to prevent mortality can range from $107,000 to $6.4 million per life or more, depending on the country's wealth. 

 

“Applying the more conservative range of WTP, we find that avoiding this loss of life translates into a WTP of between $350 billion to $21 trillion annually. The broad range of values arises because we do not know in which countries future pandemics would occur,” the study said. 

“Using the upper range of those WTP values and reducing the likelihood of extreme outbreaks by just 10 per cent cut expected deaths by 300,000 and monetised mortality losses by up to $2 trillion each year. Strategies that curtail the risk of any epidemic by half would save 1.6 million lives a year and reduce mortality costs by $10 trillion,” the study further argued.

 

According to the authors, preventing spillover at the source is rarely addressed when policymakers and multilateral organisations discuss pandemic risks—despite the fundamental role spillovers play in spreading emerging infections. To address this, the paper recommends revising the World Health Organization’s “phases of infectious disease emergence” to include a specific phase for spillover. They further coin a new paradigm—“primary pandemic prevention”—to define actions that stamp out new diseases before they spread, rather than actions that address disease outbreaks after they occur.  

 

In addition to preventing pandemics by suppressing the emergence of novel and well-known pathogens, the actions included in the paper help avoid carbon dioxide emissions, conserve water supplies, protect Indigenous Peoples’ rights and conserve biodiversity. They also prevent indirect damages not included in the cost estimates, such as psychological harms from lost jobs, lost relatives, or social isolation, delayed medical treatments, and loss or delays of education.  

 

The report provided the cost of implementing enhanced biosecurity for zoonoses around farming systems in low to middle income countries, and it extrapolated that data to the 31 countries, including India, that contains high risk of wildlife viral spillover risk.

The researchers also gave estimates for viral discovery ($120 million to $340 million), early detection and control ($217 million to $279 million), wildlife trade surveillance ($250 million to $750 million), and programs to reduce spillover from livestock ($476 million to $852 million). The most complicated estimate was reducing deforestation by half ($1.53 billion to $9.59 billion).  

 

The report also provided recommendations for research and actions to forestall new pandemics that have largely been absent from high-level discussions about prevention, including a novel call to integrate conservation actions with strengthening healthcare systems globally. The authors recommended better surveillance of pathogens that may spill from animals to people, better management of wildlife trade and hunting and reduction of deforestation.