Table 5. Estimated R₀ of Alpha and Delta variants of COVID-19 pandemic in Iran in a time span of exponential growth.

Variant	Time Span	EGR	ML	SB	SIR
Alpha	April 3-April 9, 2021	2.6422 (95% CI: 2.58–2.7)	11.3811 (95% CI: 11.28–11.48)	2.2680 (95% CI: 2.06–2.46)	12.1317 (95% CI: 12.12–12.14)
Delta	July 3-July 8, 2021	3.1002 (95% CI: 3.02–3.17)	12.0089 (95% CI: 11.89–12.12)	3.0060 (95% CI: 2.34–3.66)	23.3021 (95% CI: 23.19–23.41)