Two Deaths and 21 Severe Reactions Prompt UK to Suspend New Mosquito Virus Vaccine
UK health authorities have hit the pause button on the newly approved Chikungunya vaccine, IXCHIQ, for people aged 65 and older, following reports of two deaths and 21 severe adverse reactions in this age group. The suspension is a cautious move as investigations continue into these serious side effects.
What's Happening with the Chikungunya Vaccine?
The Chikungunya virus (CHIKV) is no stranger to tropical and subtropical regions, including parts of the Americas, Africa, Southeast Asia, India, and the Pacific. It's transmitted by mosquito bites—specifically from Aedes aegypti and Aedes albopictus species—and thankfully, it does not spread from person to person. The virus causes sudden fever and joint pain so intense it's often described as crippling.
The vaccine IXCHIQ, recently approved for use in the UK, was hailed as a breakthrough in protecting vulnerable populations from this mosquito-borne menace. However, after two deaths among seniors aged between 62 and 89 who received the jab, plus 21 other serious reactions, regulators decided to suspend its use in the over-65 age group as a precaution.
There is no change in the vaccine recommendations for adults aged 18 to 64, who can still receive IXCHIQ without restrictions.
Why the Concern Now?
The decision follows similar reports worldwide of adverse effects in older adults. Globally, 23 cases of severe reactions to the vaccine have been documented, including the two fatalities in the UK. While the exact cause of these reactions is still under investigation, the age factor appears significant.
Older adults often have weaker immune systems and more comorbidities, which can complicate vaccine responses. This isn't the first time a vaccine has shown a different risk profile in seniors, so caution is warranted.
The Bigger Picture: Chikungunya Outbreaks and Impact
Chikungunya isn't just a tropical nuisance; it can be deadly. A recent outbreak on La Reunion Island, a French overseas territory, infected over 47,500 people and resulted in 12 deaths. The virus's hallmark symptoms—high fever and severe joint pain—can linger for months, sometimes years, causing chronic arthritis-like conditions.
With climate change expanding the habitat of Aedes mosquitoes, chikungunya is becoming a growing threat in new regions, including parts of southern Europe and the southern United States. Vaccination remains a key strategy to control outbreaks and protect vulnerable populations.
What Does This Mean for Seniors and Others?
For now, seniors in the UK will have to wait for further safety data before resuming vaccination with IXCHIQ. Meanwhile, adults under 65 can continue to get vaccinated as planned.
Health officials emphasize that the benefits of vaccination still outweigh the risks for most people, especially in areas where chikungunya is endemic or outbreaks are ongoing. Preventive measures against mosquito bites—such as insect repellents, protective clothing, and eliminating standing water—remain essential.
A Quick Look at Chikungunya
Transmission: By Aedes mosquitoes, active mostly during the day.
Symptoms: Sudden fever, rash, and severe joint pain.
Duration: Acute illness lasts about a week; joint pain may persist for months.
Fatality: Rare but more common in older adults and those with underlying conditions.
What's Next?
UK vaccine regulators are working closely with international health agencies and vaccine manufacturers to analyze the data and identify the cause of the severe reactions. This may lead to updated guidelines, safer formulations, or targeted recommendations for certain age groups.
In the meantime, the suspension serves as a reminder that vaccine safety monitoring doesn't stop after approval—it's an ongoing process to ensure public health
