An epidemic of Chikungunya began in Reunion in August 2024 and was officially declared in January 2025. The community of Health professionals of Reunion brings you clear and justified details on the chikungunya epidemic and vaccination (illustration photo RB/www.imazpress.com)
In this context, a vaccine strategy has been implemented in accordance with the recommendations of the High Authority for Health (HAS) and the Ministry of Health for Reunion and Mayotte.
The IXCHIQ (VLA1553, Valneva laboratory) vaccine, authorized by the American health authorities (FDA) and the European Medicines Agency (EMA) was first offered to people over the age of 65 with comorbidities. These authorizations are based on a standardized procedure for assessing the tolerance, safety and effectiveness of the drug.
IXCHIQ is a attenuated living vaccine, that is to say it contains a weakened version of the virus, sufficient to trigger a solid immune response. It offers effective protection against the symptomatic and severe forms of chikungunya. Its effectiveness is evaluated at 98.9 %.
This vaccine is reactogenous, which means that it can cause symptoms close to those of the disease (fever, pain), sometimes marked. It is contraindicated in immunocompromised people, but well tolerated in healthy adults or with well-controlled chronic pathologies.
As a reminder, the 2005-2006 epidemic caused 258 deaths directly linked to Chikungunya and 267 additional deaths probably associated with this epidemic wave.
With the approval of the Ministry of Health, a vaccination campaign was organized by the Regional Health Agency in connection with Reunion health professionals. Upon receipt of the first doses, the campaign started in April 2025, targeting the most vulnerable people: first those over 65 with comorbidities, then adults over the age of 18 with comorbidities (excluding immunocompromised people).
People who are not eligible for the campaign organized by ARS can nevertheless access the vaccine, at their expense, according to a similar care path. Any vaccine or medication, former and recent, is subject to monitoring called pharmacovigilance. Any healthcare professional noting a serious or unexpected adverse effect must make the immediate declaration to the regional pharmacovigilance center.
In April 2025, three pharmacovigilance statements were made following the deaths of the elderly who received the vaccine. Thanks to the vigilance of hospital teams in the CHU and the pharmacovigilance network, this case was immediately reported to the Ministry of Health and the ANSM.
Two of the three serious cases reported concerned people over 80 with comorbidities.
In this context, the HAS has reassessed the benefit/risk ratio among those over 65. It has recommended to temporarily suspend the use of the IXCHIQR vaccine in this age group, pending national and international additional data. Among people aged 18 to 64 with comorbidities, the vaccine retains all its relevance. No severity alert has been identified in this population to date.
This is the principle of the benefit/risk ratio: the expected benefits of vaccination are superior to the risk identified, according to available studies. At the end of April 2025, more than 37,000 doses of the vaccine were used worldwide, including more than 6,400 in Reunion.
Reunion health professionals – Hospital and liberals – are fully engaged in evaluation and research around this vaccination. The National Institute of Health and medical Research (INSERM) has provided clear scientific responses to the points raised.
Representatives of health professionals signatory to this press release recall the importance of an individual evaluation evaluation of the expected gain in the face of potential adverse effects for each patient, and the need for a clear and secure framework for medical decisions.
Vaccination is not the only lever against chikungunya: prevention of mosquito bites remains an essential protective measure.
In addition, pregnant women at the end of pregnancy and infants less than 3 months old must show particular vigilance and protect themselves effectively from mosquito bites. To date, we have a deceased infant and 2 newborns with a diagnosis of serious encephalitis with significant risks of neurological development disorders. 153 children hospitalized in pediatrics and neonatology including 80% infants under 3 months of age.
Thus, we encourage each Reunionese aged 18 to 64 to be advised by their health professional on the interest of vaccination, in accordance with current scientific data and taking into account their medical history, pathologies and possible comorbidities.
On a daily basis, your health professionals are there to preserve the health of the population, inform you about the envisaged decisions, their reasons and their consequences.
Dr. Christine Kowalczyk President of the Regional Union of Doctors of the Indian Ocean
Dr Anne Vienne-Éxou President of the Departmental Council of the Reunion of the Order of Doctors
Dr. Claude Marodon President Delegation Order of Pharmacists Reunion-Mayotte
Chickunya, Vaccin, Tribune Libre
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