Background The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, also called 2019-nCoV) causes different morbidity risks to individuals in different age groups. This study attempts to quantify the age-specific transmissibility using a mathematical model. Methods An epidemiological model with five compartments (susceptible–exposed–symptomatic–asymptomatic–recovered/removed [SEIAR]) was developed based on observed transmission features. Coronavirus disease 2019 (COVID-19) cases were divided into four age groups: group 1, those ≤ 14 years old; group 2, those 15 to 44 years old; group 3, those 45 to 64 years old; and group 4, those ≥ 65 years old. The model was initially based on cases (including imported cases and secondary cases) collected in Hunan Province from January 5 to February 19, 2020. Another dataset, from Jilin Province, was used to test the model. Results The age-specific SEIAR model fitted the data well in each age group ( P < 0.001). In Hunan Province, the highest transmissibility was from age group 4 to 3 (median: β 43 = 7.71 × 10 − 9 ; SAR 43 = 3.86 × 10 − 8 ), followed by group 3 to 4 (median: β 34 = 3.07 × 10 − 9 ; SAR 34 = 1.53 × 10 − 8 ), group 2 to 2 (median: β 22 = 1.24 × 10 − 9 ; SAR 22 = 6.21 × 10 − 9 ), and group 3 to 1 (median: β 31 = 4.10 × 10 − 10 ; SAR 31 = 2.08 × 10 − 9 ). The lowest transmissibility was from age group 3 to 3 (median: β 33 = 1.64 × 10 − 19 ; SAR 33 = 8.19 × 10 − 19 ), followed by group 4 to 4 (median: β 44 = 3.66 × 10 − 17 ; SAR 44 = 1.83 × 10 − 16 ), group 3 to 2 (median: β 32 = 1.21 × 10 − 16 ; SAR 32 = 6.06 × 10 − 16 ), and group 1 to 4 (median: β 14 = 7.20 × 10 − 14 ; SAR 14 = 3.60 × 10 − 13 ). In Jilin Province, the highest transmissibility occurred from age group 4 to 4 (median: β 43 = 4.27 × 10 − 8 ; SAR 43 = 2.13 × 10 − 7 ), followed by group 3 to 4 (median: β 34 = 1.81 × 10 − 8 ; SAR 34 = 9.03 × 10 − 8 ). Conclusions SARS-CoV-2 exhibits high transmissibility between middle-aged (45 to 64 years old) and elderly (≥ 65 years old) people. Children (≤ 14 years old) have very low susceptibility to COVID-19. This study will improve our understanding of the transmission feature of SARS-CoV-2 in different age groups and suggest the most prevention measures should be applied to middle-aged and elderly people.
【저자키워드】 COVID-19, SARS-CoV-2, Transmissibility, compartmental model, Age-specific dynamics, 【초록키워드】 Coronavirus disease 2019, coronavirus, susceptibility, 2019-nCoV, risk, Transmission, Novel coronavirus, Features, morbidity, age, dataset, epidemiological, group, SAR, acute respiratory syndrome, individual, measure, secondary cases, highest transmissibility, FIVE, lowest, IMPROVE, Result, was used, collected, occurred, cause, groups, exhibit, mathematical, 【제목키워드】 transmissibility of SARS-CoV-2,