Chikungunya Epidemic Persists in Réunion Despite Declining Indicators

Réunion Island, France – The chikungunya outbreak, now in its fourteenth month, continues to grip Réunion Island, with health authorities noting a slight decline in surveillance indicators but a rising human toll. Between April 28 and May 4, 2025, emergency room and general practitioner visits related to chikungunya dropped, yet three new deaths linked to the virus were confirmed. An additional 28 fatalities are under investigation to determine their connection to the disease.

Current Situation

• Epidemic Still Active: Despite the decrease in medical consultations and emergency visits, the epidemic remains widespread and at a high level across the island.

• Consultations Down: Over 14,030 general medicine consultations for chikungunya were recorded in week 18, accounting for just over 10% of all medical exams. Emergency room admissions for adults dropped by 17% from the previous week.

• Regional Trends: The decline is confirmed in the South, West, and North regions. The East saw a slight increase, possibly due to localized factors or reporting delays.

• Severe Cases: To date, 66 severe cases-involving at least one organ failure-have been reported. These include 36 adults over 65 with comorbidities, 7 people under 65 (6 with comorbidities), and 23 infants under 3 months.

• Deaths: Since the start of 2025, 12 deaths have been confirmed, all among individuals aged 71 to 95. Three of these occurred in the last reporting period. Investigations are ongoing for 28 additional deaths, including that of an infant.

Context and Background

• Outbreak History: The current epidemic began in August 2024, with the number of cases surging in early 2025. The last major outbreak on Réunion was in 2005-2006, which resulted in 250 deaths.

• Transmission: Chikungunya is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Symptoms include fever, severe joint pain, rash, and fatigue. While most cases are self-limiting, severe outcomes can occur, especially in the elderly and infants.

• Vaccination Efforts: The vaccination campaign began in April 2025, prioritizing people over 65 with comorbidities. However, after reports of serious adverse events in elderly patients, vaccination with the IXCHIQ vaccine was temporarily suspended for those over 6.

Impact Beyond Réunion

• Imported Cases in Mainland France: Since January 1, 2025, 766 imported cases have been identified in mainland France, 97% of which originated from Réunion. Health authorities warn of the risk of indigenous transmission as summer approaches.

• Travel Advisory: The U.S. CDC and French authorities have issued travel health advisories, recommending vaccination and mosquito bite prevention for travelers to Réunion.

Public Health Response

• Vector Control: Authorities are intensifying mosquito control measures and urging residents to eliminate stagnant water sources.

• Vigilance: The public is advised to remain vigilant, use mosquito nets, and seek medical attention if symptoms develop.

Disclaimer:
The information in this article is based on the latest available data from health authorities and public health surveillance systems. Figures and trends may change as investigations continue and new data are released. Readers are encouraged to follow official guidance from local health authorities and consult healthcare professionals for personal health advice. The risk of chikungunya and other mosquito-borne diseases remains elevated in affected regions, and preventive measures are strongly recommended.