Global disease resurgence in 2024 shows rising health threat

Some infectious diseases saw a huge surge in 2024, with the spread attributed in part to climate change, declining vaccination rates and the advent of new pathogen variants.

The findings, part of a preliminary analysis by London-based disease forecasting firm Airfinity Ltd., seek to renew the focus on the rise of preventable and climate-sensitive diseases, as well as a coordinated global response.

By late December, the world saw dengue cases jump to a record of over 13 million, more than double last year’s number as infections nearly tripled in Central and South America, and killed almost 10,000 globally this year. Cases of pertussis, also known as whooping cough, rose almost 10 times the total number of 2023. Many others such as mpox, oropouche fever and poliomyelitis were also on the rise.

The year also saw unprecedented number of human contracting avian influenza caused by the H5N1 virus in the U.S., where 61 cases have been reported by late December. Rwanda also reported its first outbreak of Marburg virus, which can cause severe and potentially fatal hemorrhagic fever in people.

The analysis, which relied on data from 128 sources from 206 countries, found that extreme temperature and changing climate patterns contributed to the surge of diseases, some of which are caused by viruses, bacteria and parasites borne by vectors including mosquitoes and ticks.

Warmer temperatures mean some of these vectors are able to survive and reach newer regions. This year is expected to be the hottest on record, with the average global temperature reaching 1.62C above preindustrial levels in November, according to the Copernicus Climate Change Service.

Besides, falling immunization rates after the COVID-19 pandemic and emergence of new strains of diseases also contributed to the wider spread.

Mpox, the typically less contagious and milder cousin of smallpox, has killed hundreds of people this year after a more severe strain appeared in the Democratic Republic of Congo and prompted the World Health Organization to declare it as a global public health emergency for the second time. A declining immunization rates globally post-pandemic led to a comeback of measles which saw a 380% jump in the U.S. and 147% increase in Europe.

Airfinity also found that large-scale population movement and disruption in vaccine campaigns due to military conflicts led to the resurgence of polio in Afghanistan and Pakistan, the two remaining endemic countries of the diseases which affect children mostly.

“The resurgence of preventable and climate-sensitive illnesses highlights the importance of adhering to preventive measures while advancing innovation to address diseases,” said Kristan Piroeva, an analyst at Airfinity, and called for global data sharing, surveillance of trends for a coordinated public health response.