Clinical trialsCompany release

Valneva: 94% of adults still seroresponders five years after single IXCHIQ dose

Valneva SE (VALN) · Fri 13 Nov 2026

Five-year follow-up from trial VLA1553-303 shows most vaccinated adults retain neutralising antibodies above the seroresponse threshold, with older adults matching younger ones.

Valneva has reported five-year antibody persistence data for its single-dose chikungunya vaccine IXCHIQ. The data come from trial VLA1553-303 and were announced by the company on 10 November 2026.

Among 221 evaluable healthy adults, 94% still had neutralising antibody titres above the seroresponse threshold five years after vaccination. The company said adults aged 65 and older responded comparably to those aged 18 to 64.

Follow-up in the study will continue for up to ten years. Persistence data of this kind are typically used to judge how long protection-related immune responses last after a single dose, although antibody titres are a surrogate marker rather than a direct measure of clinical protection.

Valneva also cited a pilot vaccination campaign in Brazil that immunised nearly 80,000 adults. According to the company, the campaign is intended to support post-marketing studies of the vaccine.

What it means for your team

  • Five-year persistence data may feed into discussions on duration of protection and the need for boosters, though the company's summary does not address either point.
  • The comparable response in adults aged 65 and over is relevant to labelling and recommendations for older age groups.
  • The Brazilian campaign of nearly 80,000 adults is described as supporting post-marketing studies, so pharmacovigilance and real-world evidence teams may want to watch for those results.
  • The trial continues for up to ten years, so further data are expected.

Company's press release (SEC filing): Valneva SE ↗

Article written by VigiEye from the official source (Valneva SE). Claims are the company's own. AI-assisted; check the source before acting.

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