Table 3. Degradation in antiviral effectiveness due to diagnosis delay for epidemics with various reproduction numbers.

	R0
	1.2		1.5		2.0		2.5
intervention strategy	zero-delay attack rate (%)	attack rate increase (% per 12 hours delay)	zero-delay attack rate (%)	attack rate increase (% per 12 hours delay)	zero-delay attack rate (%)	attack rate increase (% per 12 hours delay)	zero-delay attack rate (%)	attack rate increase (% per 12 hours delay)
baseline	12.8		24.5		36.4		43.8
T	6.2	1.06	17.4	1.23	31.0	0.93	39.2	0.78
T+SC	4.0	0.81	13.6	1.16	25.5	0.83	33.3	1.04
T+H	3.6	0.97	12.2	1.55	25.0	1.39	32.4	1.46
T+H+SC	2.8	0.54	8.7	1.57	21.5	1.04	28.2	1.34
T+H+E	2.8	0.73	8.8	1.65	20.9	1.33	28.7	1.18
T+H+E+SC	2.4	0.49	6.7	1.67	19.1	1.27	27.1	1.02

Cumulative attack rates (% of population) are given for zero diagnosis delay (i.e. administration of antivirals at the time of symptom appearance) along with the approximate increase in final attack rate that results from each addition 12 hour delay (up to 48 hours). Results are given for different intervention strategies and for baseline (i.e. unmitigated) epidemics with four different reproduction numbers (R₀). Intervention strategies are abbreviated as follows: T – antiviral treatment of diagnosed cases, H – prophylaxis of household of diagnosed cases, E – prophylaxis of school or work contacts of diagnosed cases, SC – four weeks of school closure. In all cases diagnosis coverage is 50%.