Module 9 2021

23/03/2021

Comparison of Immuno vs. Efficacy Studies

Immuno Studies • Protection dependent on correlate • Sample size in hundreds • Technically easier • Samples collection / storage easier • Consistency easy provided labs have adequate bridging • Always possible provided adequate serology assays exist – 3rd party assays? – Technology transfers to local lab?

Efficacy Studies • ‘Gold standard’ for vaccine protection • Sample size in thousands • Technically difficult • Differing samples • Consistency difficult as clinical practice may vary between countries • May not be possible due to – epidemiology factors (e.g. pertussis), – ethical issues (e.g. HIV) or – emergency public health priorities (e.g. pandemic influenza) • Expensive and takes much longer – Need to follow-up subjects for an adequate period for sufficient clinical cases to accrue – Event driven analysis may enable expedited results

• Cheaper and quicker

– Usually primary endpoint involves sample collection ~1 month after last vaccine dose – Longer follow-up possible

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Specific Processes Used by Vaccines

Article 58 – EU Process (used by Vx and other products)

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