NEW DELHI, Oct 3: Approximately 5.1 million people in India are at risk of contracting chikungunya, a mosquito-borne viral disease known to cause debilitating, long-term joint pain and disabilities, a new study published in BMJ Global Health has issued a serious warning.
Alarmingly, the study also suggests that the disease could spread beyond current hotspots, potentially increasing the global population at risk to nearly 35 million annually, with 12.1 million in India alone.
This is the first study to employ advanced machine learning techniques to predict chikungunya’s future burden by integrating data on infection rates with environmental and socioeconomic factors. These include the presence of Aedes aegypti and Aedes albopictus mosquitoes, climate variables favourable to transmission, and economic indicators like national GDP.
The comprehensive risk maps reveal that chikungunya’s threat extends far beyond tropical regions, highlighting an urgent need for proactive prevention efforts and vaccination campaigns. With no specific antiviral treatments available and only supportive care to manage symptoms, chikungunya poses a growing and serious challenge for India’s healthcare infrastructure and public health preparedness.
The joint study by researchers from the London School of Hygiene & Tropical Medicine (LSHTM), Nagasaki University, and the International Vaccine Institute also identified vulnerable age groups and high-risk regions to help prioritise vaccine distribution.
Alongside India, Brazil and Indonesia are expected to bear significant long-term impacts, with these two countries together accounting for nearly half of the global healthcare burden caused by chikungunya.
Chronic complications – primarily persistent joint pain and disability – are projected to make up over 50% of the disease’s impact. Since its resurgence in 2004, chikungunya has emerged as a critical public health threat in more than 114 countries. Spread by the Aedes mosquitoes-commonly called yellow fever and tiger mosquitoes-the virus causes high fever and severe joint pain.
Although most patients recover in a few weeks, over half suffer from chronic joint pain and disability, and some cases may result in death. While there are no specific cures, two vaccines – Ixchiq and Vimkunya -have been approved in certain countries to prevent infection.
Previous estimates relying on outbreak surveillance have grossly underestimated the true scale of chikungunya infections. The new model predicts that 1.2-1.3% of those at risk globally may be infected each year, which, although lower than dengue’s 6%, includes alarming hotspots like Gabon, where infections could affect up to 11% of the population at risk.
Chronic illness primarily affects adults aged 40 to 60, while children under 10 and seniors over 80 face the highest risk of severe, acute symptoms.
Hyolim Kang, the lead author and Research Fellow at Nagasaki University, said, “It’s been widely thought that mosquitoes carrying chikungunya would be confined to subtropical or tropical continents, but our analysis has found that the risk extends way beyond these regions. Prevention of the spread of this disease is important for everyone.
“There are no specific antiviral therapies for chikungunya and treatment relies solely on supportive care. Not only are infections extremely painful, even the healthiest of people can be infected and left with life-long disability,” Kang said.
Sushant Sahastrabuddhe, Associate Director General at the International Vaccine Institute, added: “The potential spread of vectors carrying viruses like chikungunya won’t wait for us to carry out years of research, so it’s been extremely important to us that the modelling we’re working on is shared and used in real time to help public health professionals manage current cases and prepare for the future.”
Echoing similar concerns, senior author Kaja Abbas, Associate Professor at LSHTM and Nagasaki University, stated, “Our model-based estimates are useful to inform outbreak response immunization strategies for different age groups using the two licensed vaccines (Ixchiq and Vimkunya) in Brazil and broadly in any setting globally at risk of chikungunya outbreaks. We hope other countries will follow suit and look to prioritise regions conventional surveillance systems may have missed.” (UNI)
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