Chikungunya vaccination

Ixchiq® (VLA1553, Valneva)

• Product: Ixchiq®, prevention of disease caused by chikungunya virus (CHIKV)

• Type: live- attenuated vaccine 

• Route of administration: intramuscular

• Schedule: single dose

• Booster: the need for revaccination has not been established.

• Age: ≥12 years up to ≤ 64 years

• Recommendation:
  • Vaccination is recommended for people aged ≥12 to ≤64 years travelling to a country or region where there is an active chikungunya outbreak.
  • Outbreaks are defined as over 100 cases per 100,000 people in the past 3 months (darkest red areas) as per chikungunya outbreak map of ECDC. 
• Efficacy:
  There is no established immune correlate of protection for chikungunya. The clinical efficacy of Ixchiq® was inferred from a postvaccination CHIKV-specific neutralizing antibody titre threshold, referred to as seroresponse. It is still unclear how this translates into protection against disease in real life.
  Limited data suggest that Ixchiq® induced antibodies are able to cross-neutralize wild-type CHIKV strains from 3 CHIKV genotypes (IOL/ECSA, West African and Asian).
  In the phase 3 trial conducted in adults 98.9% of prior seronegative had a positive seroresponse at 28 days post-vaccination. This percentage was sustained up to 6 months post-vaccination (96.3%). Similar results were seen in adolescents (12 to <18 years of age). Immune response persistence was 99.5% at 12 months and 97.1% at 24 months post-vaccination (McMahon et al., 2024).
• Contra-indications:
  • Hypersensitivity to the active substances or to any of the excipients.
  • Patients with primary or acquired immunodeficiencies: hematologic or solid cancers treated with chemotherapy, immunosuppresive therapy after solid organ or hematological transplantation, congenital immunodeficiency, immunological diseases under immunosuppressive therapy or patients with HIV infection who are severely immunocompromised.
  • Pregnant woman and breastfeeding women
    • There is limited amount of data from the use of Ixchiq® in pregnant women.
    • It is unknown if Ixchiq® is excreted in human milk therefor a risk to the breastfed child cannot be excluded.
  • Patients under 12 year and over 65 year of age
• Side effects:
  The overall safety of Ixchiq® is based on an analysis of the pooled safety data from three completed phase I and III clinical studies conducted in the US on 3 610 participants ≥18 years old who received one dose of Ixchiq® with a follow-up of 6 months. Side-effects seen were tenderness (10.8%),  pain (6.1%), headache (32%), fatigue (29.4%), myalgia (23.7%), arthralgia (16.6%), fever (13.8%) and nausea (11.4%).
  Safety in adolescent participants 12 to <18 years was assessed in 502 participants in Brazil who received one dose of Ixchiq®  with a follow-up of 6 months. The most common reactions in adolescents 12 to <18 years of age were tenderness (19.9%), pain (19.3%),  headache (51.0%), myalgia (26.9%), fever (24.1%), fatigue (22.3%), nausea (15.9%) and arthralgia (12.9%).
  Ixchiq® may cause severe or prolonged chikungunya-like adverse reactions defined as fever (≥38°C) and at least one other symptom also reported for acute-stage chikungunya illness (including arthralgia or arthritis, myalgia, headache, back pain, rash, lymphadenopathy, and certain neurological, cardiac or ocular symptoms) within 30 days after vaccination. This was reported in 12.1% of participants, and was mostly mild with 1.8% of participants reporting at least one severe symptom, most commonly fever or arthralgia. Longer-lasting symptoms ≥30 days occurred in 0.4% of participants.
  On May 7 2025, EMA advised that Ixchiq® must not be used in people 65 years and above as a temporary safety measure while conducting an in-depth review following reports of serious adverse events including 2 deaths in elderly people. Many of the people affected also had other illnesses and the exact cause of these adverse events and their relationship with the vaccine have not yet been determined to date.
• Co- administration with other vaccines:
  No data on co-administration is available. Until further data on co-administration is known an interval of four weeks with other live vaccines is recommended.
  
  

Vimkunya®: not available in Belgium

• Product: Vimkunya ®, prevention of disease caused by chikungunya virus (CHIKV)
• Type: recombinant vaccine, purified virus-like particles (VLPs) consisting of CHIKV capsid protein (C) and envelope proteins E1 and E2, derived from CHIKV Senegal strain 37997
• Route of administration: intramuscular
• Schedule: single dose
• Booster: The need for revaccination has not been established.
• Age: individuals of 12 years and older
• Recommendation: The Superior Health Council (SHC) will provide a recommendation for the use of Vimkunya® as soon as this becomes available on the Belgian market.