Climate Change, Vaccine Gaps, and New Variants Drive Surge in Infectious Diseases
2024 has witnessed an alarming rise in infectious diseases, with millions of cases reported worldwide. Factors such as climate change, dropping vaccination rates, and the emergence of new pathogen variants are driving this unprecedented surge.
According to a preliminary analysis by Airfinity, a London-based disease forecasting firm, the increase in preventable and climate-sensitive diseases is a cause for concern. The findings call for a global response to mitigate these health threats and reinforce vaccination efforts.
By late December, dengue fever had reached a record high, with over 13 million cases reported—more than double the number from the previous year. The rise was particularly pronounced in Central and South America, where cases nearly tripled. Tragically, dengue led to almost 10,000 deaths globally this year. Other diseases like pertussis (whooping cough) saw a nearly tenfold increase compared to 2023, and infections such as mpox, oropouche fever, and polio also surged.
The spike in disease cases wasn’t limited to tropical regions. In the United States, an unprecedented number of human infections from avian influenza, caused by the H5N1 virus, were reported. As of December 2024, 61 people in the U.S. had contracted the virus. Meanwhile, Rwanda faced its first outbreak of the Marburg virus, a deadly disease that causes severe hemorrhagic fever.
The climate crisis is making the problem worse. Airfinity’s analysis, based on data from 128 sources across 206 countries, suggests that extreme temperatures and shifting climate patterns have contributed to the spread of vector-borne diseases. Warmer conditions allow disease-carrying mosquitoes, ticks, and other pests to thrive in new regions, expanding their reach. This year was on track to be the hottest on record, with global temperatures surpassing preindustrial levels by 1.62 degrees Celsius, according to the Copernicus Climate Change Service.
Another significant factor in the rise of these diseases is the fallout from the COVID-19 pandemic. Falling vaccination rates have left populations more vulnerable to outbreaks of preventable diseases. For instance, measles has made a comeback in some regions, with cases increasing by 380% in the United States and 147% in Europe. Similarly, mpox, a disease typically less contagious than smallpox, has taken a deadly turn, with a new, more virulent strain spreading through the Congo.
The pandemic also disrupted routine immunization campaigns, and military conflicts in regions like Afghanistan and Pakistan have hindered efforts to vaccinate children, leading to the resurgence of polio—one of the last endemic diseases in these areas.
Climate Change Fuels the Spread of Diseases
The impact of climate change on global health is becoming undeniable. Rising temperatures create favorable conditions for diseases that were once confined to tropical regions. Mosquitoes, ticks, and other vectors responsible for spreading diseases such as dengue, malaria, and Zika, are expanding their range into previously unaffected areas.
In some regions, this shift in vector patterns has led to an uptick in illnesses that are directly linked to climate change. For example, the growing spread of dengue fever across Central and South America is being driven by warmer temperatures, which allow mosquitoes to breed in larger numbers and in regions that were once too cold for their survival.
- Warmer temperatures allow mosquitoes to breed in areas previously unaffected.
- Increased rainfall and humidity create ideal breeding conditions for disease vectors.
- Longer, warmer seasons contribute to a longer period of disease transmission.
According to experts, this is not just a short-term trend. As the Earth continues to warm, we can expect the expansion of diseases typically found in tropical climates into more temperate regions. This will put more people at risk and put further pressure on public health systems worldwide.
Vaccination Gaps and Emerging Variants Add to the Crisis
While climate change plays a significant role in the spread of diseases, the decline in vaccination rates post-pandemic is equally concerning. Immunization campaigns were disrupted during COVID-19 lockdowns, and now, in many places, vaccination rates have yet to return to pre-pandemic levels.
This has left populations vulnerable to outbreaks of diseases that were once under control. Measles, for example, is making a troubling comeback. In the United States, the number of cases has surged by 380% compared to the previous year, while Europe has seen a 147% increase in measles cases.
Additionally, new variants of viruses like mpox and pertussis are contributing to the resurgence of these diseases. While mpox typically causes mild symptoms, a more severe strain has emerged in the Congo, leading the World Health Organization to declare it a global public health emergency for the second time this year.
The problem is compounded by the emergence of new strains of various diseases, making it more difficult to control their spread. These evolving pathogens are capable of bypassing immunity in populations that were previously protected, further driving the resurgence of diseases like pertussis and avian influenza.
The Role of Global Coordination in Tackling the Crisis
The findings of Airfinity’s report highlight the urgent need for coordinated global action to combat the rising tide of preventable diseases. As the world becomes more interconnected, the spread of infectious diseases is no longer confined to specific regions. Public health systems must be prepared to address not only the immediate threats posed by these diseases but also the long-term challenges posed by climate change and vaccination gaps.
There is hope, however. Increased awareness of the connection between climate change and disease transmission could lead to more proactive public health measures. Countries are beginning to invest more in climate-resilient healthcare infrastructure, and there are signs that international vaccination campaigns are picking up pace again. But for these efforts to succeed, global cooperation and commitment are essential.
The year 2024 has been a stark reminder of the growing health threats we face as a planet. To prevent further devastation, a united and urgent response is required to tackle the combined challenges of climate change, declining vaccination rates, and the rise of new pathogen variants.
