Table 1 Summary of model parameters.

R₀

Basic reproduction number, original variant

2.5

^54,55

\({R}_{0}^{{{{{{{{\rm{new}}}}}}}}}\)

Basic reproduction number, Alpha (B.1.1.7)-like variant

3.75

^6,7

\({R}_{0}^{{{{{{{{\rm{new}}}}}}}}}\)

Basic reproduction number, Delta (B.1.617.2)-like variant

4.92

⁶¹

R_e

Effective reproduction number, original variant

1.1

Computed using the method in⁶⁰

\(\hat{c}\)

Average contact rate prior to the epidemic (individuals/day)

14.9

⁵⁸

ϵ

Probability of transmission per contact, original variant

2.4 × 10⁻²

From \({R}_{0}=\hat{c}\epsilon /\gamma =2.5\)

ϵ^Alpha

Probability of transmission per contact, Alpha-like variant

3.6 × 10⁻²

From \({R}_{0}=\hat{c}{\epsilon }^{Alpha}/\gamma =3.75\)

ϵ^Delta

Probability of transmission per contact, Delta-like variant

5.4 × 10⁻²

From \({R}_{0}=\hat{c}{\epsilon }^{Delta}/\gamma =4.92\)

c

Average contact rate of non-compliant individuals starting November 16, 2020 (individuals/day)

8.8 (0.5 − 15)

Obtained from solving R_e(0) = 1.1

r₁

Ratio between contact rates of compliant and non-compliant individuals

0.34 (0.01 − 1)

Assumed, control parameter

r₂

Ratio between contact rates of vaccinated and non-compliant individuals

1.5 (1, 1.5)

Assumed, control parameter

1/α

Average duration of latent period (days)

4 (2–6)

^54,55,56

1/γ

Average duration of infectious period (days)

7 (5–9)

⁵³

δ

Rate of moving to compliant state (1/day)

4 × 10⁻⁵ (10⁻⁶ − 10⁻⁴)

Assumed, control parameter

1/μ₀

Average duration of compliant state when there is no vaccination (days)

30 (7 − 30)

Sensitivity analyses

μ₁

Parameter describing how loss of compliance increases depending on vaccination coverage (1/day)

0, 0.3

Sensitivity analyses

υ

Vaccine uptake rate (1/day)

(5, 60) × 10⁻³

Based on vaccination data in⁴²

ω

Vaccine efficacy in conferring protection against becoming infected

0.6 (0.55 − 0.95)

^{24,25,26,27,29,31,32,80,82}, control parameter

Threshold of infectious individuals for strengthening/relaxation of the lockdown (individuals)

50 − 500

Sensitivity analysis

Average contact rate during strengthened lockdown (individuals/day)

3

Sensitivity analysis