# COVID-19 Vaccine Priority Strategy Using a Heterogenous Transmission Model Based on Maximum Likelihood Estimation in the Republic of Korea

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## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Data

#### 2.2. Maximum Likelihood Estimation

#### 2.3. Heterogeneous Population Model of COVID-19 Epidemic in Republic of Korea

#### 2.4. Vaccine Priority Strategy

## 3. Results

#### 3.1. Maximum Likelihood Estimation

#### 3.2. Parameterization of the Mathematical Model

#### 3.3. Vaccine Priority

## 4. Discussion

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## Abbreviations

COVID-19 | Severe acute respiratory syndrome-coronavirus 2 |

MLE | Maximum likelihood estimation |

KDCA | Korea Disease Control and Prevention Agency |

HCW | Healthcare worker |

## References

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**Figure 1.**Flowchart of the mathematical model of the COVID-19 epidemic in Korea considering group heterogeneity.

**Figure 3.**Estimated transmission rates. Purple, blue, green, and yellow represent the HCW, underage, adult, and senior groups, respectively.

**Figure 4.**The population-adjusted risk of disease transmission (

**A**), and risk of being infected (

**B**). Cyan and red boxes denote extrinsic (from or to different groups) and intrinsic (among same group hosts) factors, respectively.

**Figure 5.**The parameter estimation results. Red squares and dark curves denote the real data and model simulation results using data-fitted parameters, respectively. (

**A**) reproductive number, (

**B**) daily incidence, and (

**C**) cumulative incidence.

**Figure 6.**Confirmed case number of groups (

**A**), and population-adjusted case number per 100,000 (

**B**). Purple, blue, green, and yellow denote the HCW, underage, adult, and senior groups, respectively.

**Figure 7.**Best vaccination order for 120 scenarios. (

**A**) minimizing incidence, and (

**B**) minimizing mortality.

From | |||||

1: HCW | 2: Underage | 3: Adult | 4: Senior | ||

1: HCW | 8.3315 | 0.0029 | 0.4831 | 0.0230 | |

To | 2: Underage | 0.0667 | 0.5246 | 0.1146 | 0.0001 |

3: Adult | 0.0001 | 0.0019 | 0.2706 | 0.0091 | |

4: Senior | 0.2358 | 0.0010 | 0.1226 | 0.6444 |

Phase | Period | Value |
---|---|---|

1 | 1 August 2020–11 August 2020 | 0.9058 |

2 | 12 August 2020–3 November 2020 | 1.2134 |

3 | 4 November 2020–23 November 2020 | 1.2317 |

4 | 24 November 2020–7 December 2020 | 1.2273 |

5 | 8 December 2020–22 December 2020 | 1.2105 |

6 | 23 December 2020–18 January 2021 | 0.6205 |

7 | 18 January 2021–15 February 2021 | 0.8696 |

8 | 15 February 2021–25 February 2021 | 1.0404 |

Symbol | Description | Value | Reference |
---|---|---|---|

$1/\kappa $ | average duration from exposed to infectious | 2.1 days | [17,18,19] |

$1/\alpha $ | average duration from infectious to quarantine | 6 days | [17,18,19] |

$1/\gamma $ | average duration from quarantine to recover or death | 25 days | [15] |

${f}_{1}$, ${f}_{3}$ | fatal rate of adult (include HCW) | 0.0031 | [15] |

${f}_{2}$ | fatal rate of underage | 0 | [15] |

${f}_{4}$ | fatal rate of senior | 0.1072 | [15] |

**Table 4.**Simulation results depending on the different vaccination orders in the same scenario (vaccine supply for each group: (0.5, 1.5, 1.5, and 1.5)M, daily dose number: $0.1M$, and reproductive number: $1.2$).

Vaccination Order | Additional Case (Reduction) | Additional Fatality (Reduction) |
---|---|---|

without vaccination | 170,389 | 2568 |

1-4-3-2 | 132,097 (22.47%) | 1907 (25.75%) |

1-3-4-2 | 126,104 (25.99%) | 1934 (24.68%) |

3-1-4-2 | 124,389 (27.00%) | 1934 (24.68%) |

4-1-3-2 | 132,489 (22.24%) | 1901 (25.96%) |

4-3-1-2 | 131,129 (23.04%) | 1906 (25.76%) |

3-4-1-2 | 124,920 (26.69%) | 1927 (24.95%) |

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**MDPI and ACS Style**

Ko, Y.; Lee, J.; Kim, Y.; Kwon, D.; Jung, E.
COVID-19 Vaccine Priority Strategy Using a Heterogenous Transmission Model Based on Maximum Likelihood Estimation in the Republic of Korea. *Int. J. Environ. Res. Public Health* **2021**, *18*, 6469.
https://doi.org/10.3390/ijerph18126469

**AMA Style**

Ko Y, Lee J, Kim Y, Kwon D, Jung E.
COVID-19 Vaccine Priority Strategy Using a Heterogenous Transmission Model Based on Maximum Likelihood Estimation in the Republic of Korea. *International Journal of Environmental Research and Public Health*. 2021; 18(12):6469.
https://doi.org/10.3390/ijerph18126469

**Chicago/Turabian Style**

Ko, Youngsuk, Jacob Lee, Yeonju Kim, Donghyok Kwon, and Eunok Jung.
2021. "COVID-19 Vaccine Priority Strategy Using a Heterogenous Transmission Model Based on Maximum Likelihood Estimation in the Republic of Korea" *International Journal of Environmental Research and Public Health* 18, no. 12: 6469.
https://doi.org/10.3390/ijerph18126469