Table 3 Age groups and compartmental structures of dynamic models considering age structure

0–15, 15–29, 30–59, 59 + 

S_i,E_i,A_i,M_i,H_i,C_i,R_i

Susceptible (S_i), exposed (E_i), asymptomatic (A_i), mild (M_i), severe (H_i), critical (C_i), recovered (R_i) in age group i

[32]

0–9, 10–19, …, 70–79, 80 + 

S_iE_iA_iI_iH_iR_iD_i

Susceptible (S_i), latently infected (E_i), asymptomatic infectious (A_i), infectious individuals with symptoms/clinically ill (I_i), hospitalized patients (H_i), recovered (R_i), death due to disease (D_i) in group i

[33]

0–14, 15–49, 50–69, 70–80, 80 + 

S_iE_iL_iI_iR_iT_piA_siS_siS_viC_riR_diD_i

Susceptible (S_i), exposed (E_i), post latency (L_i), infectious (I_i), undocumented recovered (R_i), tested positive (T_pi), asymptomatic (A_si), symptomatic (S_si), severe (S_vi), critical (C_ri), dead (D_i), documented recovered (R_di) in age group i

[34]

0–14, 15–49, 50–69, 70 + 

S_ijE_ijI_ijQ_ijH_ijR_ijD_ij

Susceptible (S_ij), exposed (E_ij), presymptomatic (Ip_ij), mild to moderate (I_mij), severe (I_sij), quarantined and exposed (Q_Eij), pre-symptomatic and isolated (Q_Ipij), mild to moderate and isolated (Q_Imij), severe and isolated (Q_Isij), isolated (Q_ij), admitted to hospital (H_ij), pre-ICU (P_ICUij), ICU (H_ICUij), recovered (R_ij), dead (D_ij) in age group I and health status j

[35]

0–10, 10–20, …, 60–70, 70 + 

S_iV_iE_iE_viA_iA_viI_iQ_iR_iR_viD_i

Susceptible (Si), vaccinated (V_i), exposed (Ei), exposed and vaccinated (E_Vi), asymptomatic (A_i), asymptomatic and vaccinated (A_Vi), symptomatic (I_i), isolated (Q_i), recovered (R_i), recovered and vaccinated (R_Vi), death (D_i) in age group i

[36]