Table 1.

Consider non-inferiority trials designed with primary analysis to rule out the non-inferiority margin, δ, assuming vaccine efficacy of the experimental (EXP) and active control (AC) vaccines is equal.

From placebo-controlled RCT				For the non-inferiority trial
Number events	Vaccine efficacy	Hazardratio	HR upper limit 95% CI	NI margin δ	NI margin δo	HA: EXP/PLAhazard ratio	NI trial# events*	Maximum EXP/AC hazardratio ruling out
								δ **	δo **
175	95%	0.05	0.0855	3.421	9.790	0.05	34	1.631	3.795
350	95%	0.05	0.0730	3.700	11.454	0.05	31	1.686	4.038
175	90%	0.10	0.1525	2.561	5.486	0.10	54	1.456	2.880
350	90%	0.10	0.1348	2.724	6.207	0.10	48	1.490	3.071
175	80%	0.20	0.2845	1.875	2.940	0.20	112	1.282	1.972
350	80%	0.20	0.2566	1.974	3.260	0.20	97	1.310	2.110
175	70%	0.30	0.4162	1.550	2.010	0.30	225	1.189	1.535
350	70%	0.30	0.3781	1.626	2.213	0.30	184	1.212	1.638
175	60%	0.40	0.5480	1.351	1.527	0.40	470	1.126	1.271
350	60%	0.40	0.4997	1.415	1.674	0.40	355	1.147	1.354

RCT: randomized controlled trial; CI: confidence interval; HR: hazard ratio; NI: non-inferiority; PLA: placebo.

^*Calculated assuming 90% power when vaccine efficacy of the experimental (EXP) and active control (AC) vaccines is equal, using a statistic having 2.5% false positive error when δ is the true EXP/AC hazard ratio.

^**This represents the highest estimated experimental (EXP) to active control (AC) estimated hazard ratio that yields a positive result in the non-inferiority trial.