The floodwaters brought by Hurricanes Helene and Milton have already done tremendous damage across the Southeast. In addition to the physical destruction, there’s another silent danger: the mosquitoes that will follow.
As a scientist who has spent my entire professional career developing countermeasures like vaccines against mosquito-borne diseases, such as malaria and dengue fever, we cannot ignore the danger posed by climate change and its effect on infectious diseases. For now, the risk of widespread tropical mosquito-borne disease outbreaks in the United States is low, but we are quickly approaching the point where climate change leading to more severe storms and hurricanes could contribute to local transmission of diseases seen elsewhere in the world.
We can and should continue to reduce our emissions and mitigate the effects of climate change. But we would be remiss to exclude developing medical countermeasures from the United States’ natural disaster and emergency preparedness efforts.
It has long been thought that hurricane winds mostly killed off most disease-bearing mosquitoes in the United States, and only “nuisance” mosquitoes spawned in a flood’s aftermath. But there is growing evidence, in the aftermath of Hurricane Irma, that post-storm stagnant water is leading to the proliferation of mosquitoes capable of transmitting human pathogens. Warmer temperatures from climate change are contributing to perfect conditions for these pathogens to spread.
Many of these pathogens did not previously circulate in the United States, including West Nile, dengue, Zika, and chikungunya viruses. In addition to increasing natural disasters, the threat of these diseases is growing as climate change and global warming extend the mosquito transmission season. This was recently illustrated by Dr. Anthony Fauci contracting West Nile virus near his home in Washington, D.C., and commenting he “had never felt so ill in my life.” Even malaria, which the United States eradicated after tremendous effort in the 1950s, has seen cases of local transmission in the last year in states such as Maryland and Florida.
For many of these diseases, few countermeasures exist. Malaria has two new vaccines that are beginning to be rolled out in Africa. Dengue has one FDA-approved vaccine with limited availability for adults and no FDA-approved vaccine for children. The rest have very little by way of treatment or prevention.
Failing to take a proactive stance against these emerging viral pathogens assumes an unacceptable risk. Estimates are that dengue and other mosquito-borne viruses will spread throughout the United States in the coming years. We have some safeguards in place, but there is a need to establish more. The National Institutes of Health’s priority pathogens pipeline focuses on vaccine development for high-priority pathogen threats. While vaccine and therapeutic countermeasures could save thousands of lives, they are rarely profitable. To help overcome this issue, the U.S. government, in addition to the NIH program, could establish an advance market commitment (AMC) to find preventative vaccines and therapeutics for these diseases.
An AMC works as an incentive: In exchange for a product that meets pre-specified targets (say, a West Nile antiviral that reduces severe infections by a certain percent or a dengue vaccine that is more effective and cheaper than the current ones), the government guarantees it will buy a certain number of doses. By committing to buy doses of a new vaccine or countermeasure that meets pre-specified efficacy thresholds and secures FDA approval, developers are given an assured market, eliminating some of the uncertainty that discourages research in less obviously profitable areas.
The long-term benefits outweigh the short-term costs. We have a chance to avert needless illness and death exacerbated by global warming and climate change-induced weather events. The United States can advance global health by funding vaccines and therapeutic research for diseases that sicken millions of people each year globally. We may not be able to stop climate change, but we can mitigate the spread of infectious pathogens on our shores.
Dr. Kirsten Lyke is a professor of medicine and a physician-scientist at the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine and a member of the National Academy of Medicine.