Table 1.

Inputs used for the sensitivity analysis of key parameters

Parameter	Parameter effect	Best estimate	Lower bound	Upper bound
Seasonality-scaling factor (dimensionless)a	Strength of seasonal forcing on infectiousness per exposure	0.30 [6]	0.20	0.40
Emerging variant severity (dimensionless)	Multiplicative probability of severe disease for each new emerging variant	1.00	0.80	1.20
Emerging variant timing	Impact of when novel variants emerge and become dominant	3.5 months before peak winter	− 1 month	+ 1 month
Vaccine infection-blocking (%)	Infection-blocking effect of vaccination (remainder is severe disease prevention)	0.85b	0.60	0.95
Emerging variant immune evasion (%)	Impact of immune evasion on variant infectiousness	0.25	0	0.50
Emerging variant infectivity (ratio)	Multiplicative probability of transmission per exposure for each emerging variant	1.25	1.10	1.40

No effect was observed from varying daily vaccine booster capacity (results not shown) from 1500 (best estimate) to 750 doses (lower bound) and 2250 (upper bound) per day in a simulated population of 100,000 people following default timing to start administering doses

^aSee Electronic Supplementary Material Figure S2 for the seasonality profile

^bAs shown in Electronic Supplementary Material Figure S1