Module 9 2024

03/09/2024

New Vaccine : Efficacy

Sample size depends on

• the incidence of the evaluated endpoint

• the expected efficacy

• and the statistical power of the trial

As a consequence, vaccine trials are… • Often large and expensive trials • Incidence may vary over time/from one region to another/ … • Study may be not feasible if incidence is low (e.g. meningococcus C, B)

- HPV: 20,000 - Pneumococcal conjugate: 38,000 - Rotavirus trials: > 60,000 (to rule out risk of intussuception)

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New Vaccine : Immune Correlates and Efficacy

Immunological correlates of protection

• Definition - a laboratory parameter that has been shown to be associated with protection from clinical disease • Can be used to evaluate the efficacy of a vaccine when a correlate of protection has been established iti

• e.g. anti- HBS ≥ 10 mIU/ml = accepted correlate of protection for hepatitis B

However … • Correlates are unknown for most of the diseases for which prophylactic vaccines are needed • For example - malaria, tuberculosis , CMV, HIV, HCV, etc…). • For new vaccines without correlates, efficacy data are theoretically requested for licensure

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