Chikungunya Vaccine

Adults ≥18 years at increased risk of chikungunya virus exposure: travelers to endemic/epidemic areas in the Americas, Africa, South/Southeast Asia, and Indian Ocean islands. Laboratory workers handling chikungunya virus. Residents of areas with active or recent outbreaks. Particularly relevant given geographic expansion of Aedes aegypti and Aedes albopictus vectors into temperate regions.

Severe allergic reaction (anaphylaxis) to a previous dose or any component. Immunocompromised individuals including those on immunosuppressive therapy (live attenuated vaccine). Pregnancy — avoid conception for at least 30 days after vaccination. Moderate to severe acute illness (defer until recovery).

Very common (≥1/10): headache (31%), fatigue (28%), myalgia (24%), arthralgia (16%), injection site pain (13%), fever (14%), nausea (10%). Common (1–10%): injection site erythema, swelling, malaise. Transient chikungunya-like symptoms may occur 3–14 days post-vaccination (joint pain, fever) — generally mild and self-limiting. Rare: severe arthralgia requiring medical attention.

Single 0.5 mL dose, intramuscular injection in the deltoid muscle. No booster currently recommended — durability of immune response beyond 2 years under study. Administer ≥14 days before potential exposure. Store at +2°C to +8°C, protect from light.

Phase 3 trial (NCT04546724): 98.9% seroconversion rate (neutralizing antibodies ≥PRNT80) at day 28 post-vaccination. 263.5 GMT fold-rise from baseline. Antibody persistence: ≥96% seropositive at 6 months, data emerging for 12–24 months. No efficacy trial against clinical disease (approved based on immunogenicity under Accelerated Approval pathway).

Do not administer concurrently with other live vaccines unless data supports co-administration — general recommendation of same day or ≥4 weeks apart. No data on co-administration with travel vaccines (yellow fever, Japanese encephalitis). Inactivated vaccines can be given at any interval. Immunoglobulins may reduce immune response.

Not approved for individuals <18 years (studies ongoing in pediatric populations). Transient arthralgia may be more pronounced in older adults and persons with pre-existing joint conditions. Avoid pregnancy for ≥30 days post-vaccination. Breastfeeding: insufficient data, assess risk-benefit. Immunocompromised: contraindicated (live vaccine).