The United States is advising travellers aged 60 and up to hold off on getting the chikungunya vaccine while it looks into reports of possible side effects, including heart problems, neurological issues and even death.
The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) posted a notice on May 9 about the complications from the vaccine, which is sold under the name Ixchiq from manufacturer Valneva.
“As of May 7, 2025, 17 serious adverse events, including two that resulted in death, have been reported in individuals 62 through 89 years of age who received Ixchiq during postmarketing use globally,” the notice warned.
Health Canada, for its part, said it is monitoring the safety of Ixchiq and will take “appropriate action” if new information emerges that could change the vaccine’s benefit-risk profile.
The agency has not issued any warning against its use in older adults.
Chikungunya is a virus spread to people through mosquito bites. It’s mostly found in parts of the Americas, Asia, and Africa, with the occasional outbreak in Europe.
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The illness causes symptoms similar to dengue and Zika — most notably a high fever and severe joint pain that can be long-lasting. Other symptoms include swelling, muscle aches, headache, nausea, fatigue and a rash.
About 100 to 200 cases are reported annually among U.S. travellers.
The latest data from the Public Health Agency of Canada shows that as of Dec. 9, 2014, 320 confirmed and 159 probable cases of chikungunya have been identified in Canada among travellers returning from affected areas in both the Americas and the Asia-Pacific region.
The vaccine is available in both Canada and the U.S. for travellers heading to countries where the risk of catching chikungunya is higher. The shot contains a live, weakened version of the chikungunya virus and may cause symptoms similar to those of chikungunya disease.
But last month, a panel of vaccine experts who advise the CDC heard about an investigation into six people 65 and older — most of them with other medical problems — who became ill with heart or brain symptoms less than a week after vaccination.
One person died from encephalitis. More than 10 other similar cases have been reported in people from other countries.
The U.S. advisers then voted to issue a precaution for people 65 and older about getting the vaccine.
European regulators are also looking into the issue and restricting its use.
“Given that studies on Ixchiq mainly involved people below 65 years of age and the vast majority of serious cases concerned people 65 years of age and above, the Committee is temporarily recommending restricting the use of vaccine,” a statement by the European Medicines Agency said on May 7.
— With files from The Associated Press
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