United States: The US government has advised American travelers who are 60 and older not to receive the chikungunya vaccine as it assesses the possible side effects.
US Issues Warning
Late last week, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) put notices on the vaccine Valneva’s Ixchiq.
Chikungunya is a crippling tropical disease which is transmitted by mosquito bites and is characterized by fever and joint pain.
Approximately 100 to 200 cases are reported each year among US travelers.
In 2014, the government started to recommend a vaccine composed of the weakened chikungunya virus to US adults who travel to countries where chikungunya is a problem.
FDA and CDC Recommend Pause in Use of Ixchiq (Chikungunya Vaccine, Live) in Individuals 60 Years of Age and Older While Postmarketing Safety Reports are Investigated: FDA Safety Communication https://t.co/h1aKUQPT8t pic.twitter.com/9NxfSK97Rl
— US FDA MedWatch (@FDAMedWatch) May 12, 2025
Rare but Serious Reactions Prompt Investigation
However, in the last month, members of a committee that advises the CDC on vaccines heard about an investigation into the cases of six people 65 and older, most of them suffering from other medical conditions, who developed heart or brain symptoms less than a week after immunization.
Over 10 other similar cases have been reported in people from other countries, AP News reported.
The issue is also of interest to European regulators. The US advisers decided to give out a precaution to people 65 years and older regarding the vaccine.
They also suggested that another chikungunya vaccine — Bavarian Nordic’s Vimkunya (that also has US Food and Drug Administration regulatory approval) — should be provided for people aged 12 years and above traveling to mosquito-infested regions where the mosquito-borne disease is spreading, AP News reported.
CDC officials have not yet said whether they will accept those recommendations or not.