Climate change is altering the world’s disease landscape, cultivating conditions ripe for human illness to spread in new places. A growing body of research shows it’s also disrupting one of the most effective tools to protect public health: vaccines.
The World Health Organization (WHO) estimates that global immunization efforts have saved more than 154 million lives over the past five decades. However, extreme weather and global warming can destroy crucial vaccine stocks, impede transport and distribution and reduce effectiveness, according to a new study published in the journal Nature Climate Change.
Meanwhile, hesitancy to accept vaccination rose sharply across the board in the aftermath of the COVID-19 pandemic, and a contingent of global politicians continues to express anti-vaccine rhetoric, including Robert F. Kennedy Jr., tapped by President-elect Donald Trump to lead the Department of Health and Human Services during his administration. Experts say that these combined factors create a “perfect storm” that could leave people less protected in the new era of climate-fueled disease.
Climate-Related Disease Outbreaks: In many regions, the warmer and wetter conditions brought by climate change allow bacteria to thrive. Low-income countries are often the hardest hit.
Cholera—a severe intestinal disease—is a prime example. Since 2021, there has been an uptick in cholera outbreaks across the globe, exacerbated by extreme weather, according to the WHO. In Africa, major flooding and above-normal hurricane seasons have increased outbreak severity and regional spread by giving ample opportunity for the disease-causing bacterium Vibrio cholerae to spread into drinking water.
“Cholera in Africa is a climate change issue,” Jean Kaseya, director general of Ethiopia-based Africa Centres for Disease Control and Prevention, said earlier this year.
A 2022 study found that more than half of known human pathogenic diseases can be aggravated by climate change. This includes many vector-borne illnesses such as dengue and malaria, which are projected to spread to new areas as rising temperatures and increased rainfall create more favorable breeding conditions.
Following Hurricanes Milton and Helene in September and October, Florida saw a small rise in dengue fever cases as mosquitoes thrived in the standing water left behind by flooding. Puerto Rico is in the midst of a severe dengue outbreak, with more than 3,000 cases as of September 2024—over double the number reported in 2023. Research presented at the annual meeting of the American Society of Tropical Medicine and Hygiene earlier this month projects that climate change could be responsible for a roughly 60 percent increase of dengue cases by 2050, NBC News reports.
“Climate change is already reshaping infectious disease patterns by altering underpinning factors like temperature, rainfall, and species distribution,” Alessandro Siani, a researcher at the University of Ports
