Scientists probe immune system secrets behind vaccines that protect for decades

NCT ID NCT05801978

First seen Jul 17, 2026 · Last updated Jul 17, 2026

Summary

This study compares two vaccines with very different track records: the yellow fever vaccine, which protects for decades after a single shot, and the seasonal flu vaccine, whose protection fades quickly. Healthy adults aged 18–50 receive either the yellow fever or flu vaccine, and researchers collect blood samples over time to analyze immune responses. The goal is to identify biological signals that predict long-lasting immunity, which could guide the development of more durable vaccines in the future.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance
Live attenuated yellow fever vaccine (YF-17D) or quadrivalent seasonal influenza vaccine
What this could lead to
If successful, this research could reveal biological markers that predict long-lasting vaccine protection, helping design better vaccines in the future.
What could go wrong
This is an observational comparison, not a test of new treatments. The findings may not translate into practical improvements for vaccine development.

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As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Study contacts

  • Contact

    Phone: •••-•••-•••• Email: •••••@•••••

Locations

  • Emory University Hospital

    RECRUITING

    Atlanta, Georgia, 30322, United States

    Contact Phone: •••-•••-•••• Email: •••••@•••••

  • Emory Winship Cancer Institute

    RECRUITING

    Atlanta, Georgia, 30322, United States

    Contact Phone: •••-•••-•••• Email: •••••@•••••

  • The Hope Clinic of Emory University

    RECRUITING

    Decatur, Georgia, 30030, United States

    Contact Phone: •••-•••-•••• Email: •••••@•••••

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