Chikungunya vaccination
In order to prevent infection with chikungunya the traveller should be advised on mosquito bite prevention. For certain travellers vaccination might be recommended.
There are currently two chikungunya vaccines available: Vimkunya® which is a non-live recombinant vaccine and Ixchiq® which is a live -attenuated vaccine.
Recommendation for vaccination
- Recommended for all travellers to an area with an active outbreak, as indicated in the country-specific information page.
- Consider vaccination in people travelling to moderate risk areas taking into account additional factors such as the duration of the journey (e.g. > 3 months), frequent travel (resulting in a comparable cumulative exposure) and underlying conditions which might increase the risk of more severe chikungunya disease.
- Vaccination is not indicated for travellers to areas with low-level circulation, localised small clusters (e.g. France or Italy) or areas where only the vector is present.
- Vaccination is also not recommended for people who have had a laboratory-confirmed infection with chikungunya, as the infection is presumed to provide lifelong immunity.
Choice of vaccine
- Vimkunya® is preferred at present in light of reported serious adverse events associated with Ixchiq®.
- The use of Ixchiq® is restricted to selected cases in healthy individuals aged 12–60 years, preferably within a specialized travel clinic.
- While no direct comparative trials are available Vimkunya® seems to initiate a slightly earlier immune response compared to Ixchiq® in 46,6% of the study population.
- Ixchiq® currently has follow-up data up to 3 years showing persistence of the seroresponse rate. Vimkunya® currently has data with seroresponse rate up to 6 months of 85% in adolescents and younger adults and 76% in older adults, which is noticeably lower compared with rates at 14-21 days in both age groups.
Schedule
- Both Vimkunya® and Ixchiq® are administered as a single dose, preferably at least 14 days prior to travel.
- The need for a booster dose has not been established
Vimkunya®
- 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
- Age: individuals of 12 years and older
- Efficacy: there is no established immune correlate of protection for chikungunya. Efficacy is inferred from postvaccination CHIKV-neutralizing antibody levels (seroresponse), but how this translates to real-world protection remains unclear. Among adolescents and adults (12 to 64 years) seroresponse rates were 46.6% at Day 8, increasing to 96.8% at Day 15 and 97.8% at Day 22, with 85.5% maintained at 6 months. In older adults (≥65 years), seroresponse reached 82.3% at Day 15 and 87.3% at Day 22, declining to 75.5% at 6 months.
- Contra- indications:
- severe allergic reaction to vaccine components
- children <12 years of age, since there are no data
- Pregnancy and breastfeeding: data are lacking, vaccination may be considered if travel is unavoidable.
- Side-effects: the most common reactions were injection site pain (24.0%), fatigue (17.8%), headache (16.7%) and myalgia (16.5%). Other common reactions are chills, arthralgia, malaise and nausea.
- Co-adminsitration with other vaccines: there are no data on co-administration, but based on the vaccine platform interference with other vaccines is not expected.
Ixchiq ®
- Type: live- attenuated vaccine derived from the strain isolated from the outbreak in La Réunion in 2006.
- Route of administration: intramuscular
- Age: ≥12 years up to 60 years
- Efficacy: there is no established immune correlate of protection for chikungunya. Efficacy is inferred from postvaccination CHIKV-neutralizing antibody levels (seroresponse), but how this translates to real-world protection remains unclear. In adults (≥18 years), seroresponse rates were 1.6% at Day 7, rising to 98.9% at Day 28 and persisting at 96% at Year 3. %. Similar results were seen in adolescents 12 to <18 years with seroresponse 98.8% at Day 28, sustained at 99.1% at 6 months and 98.3% at 12 months.
- Contra-indications:
- severe allergic reaction to vaccine components
- immunocompromised individuals
- pregnant and lactating women
- children <12 years of age, since there are no data
- Not recommended:
- people aged ≥ 60 years, in alignment with yellow fever vaccine guidance
- frail individuals or individuals with several comorbidities such as cardiovascular disease, diabetes mellitus or chronic kidney disease.
- if the use of Ixchiq® is considered in one of these categories, it should be done after a thorough individual risk–benefit assessment in a travel clinic.
- Side effects:
- Common adverse reactions to Ixchiq® include injection site tenderness (10.8%) and pain (6.1%), as well as systemic symptoms such as headache (32%), fatigue (29.4%), myalgia (23.7%), arthralgia (16.6%), fever (13.8%), and nausea (11.4%).
- Serious adverse reactions have been reported, particularly in individuals aged ≥60 years and those with multiple or uncontrolled chronic conditions. Severe reactogenicity or chikungunya-like reactions may lead to clinical deterioration, including malaise, reduced appetite, worsening of underlying diseases, and neurological complications (e.g. confusion, encephalopathy, encephalitis), potentially resulting in falls, hospitalization, or death.
- Co- administration with other vaccines:
No data are available on co-administration. Pending data, an interval of at least four weeks between Ixchiq® and other live vaccines is recommended. If this is not feasible, priority should be given to Stamaril® due to the higher risk and severity of yellow fever. Concomitant administration with non-live vaccines is preferably avoided, and an interval of about two weeks is advised when possible to distinguish possible side-effects.