TABLE.

COVID-19 Epidemiological Models Incorporating Effects of Different Variants of SARS-CoV-2 and/or Impact of Vaccines

Model TypeLocation of Data UsedResearch QuestionKey Variables/Parameters ConsideredReference
Two-variant compartmental modelUSAAssess the effect of VOC B.1.1.7 on the US pandemic trajectory in Jan-Apr 2021SARS-CoV-2 immunity from previous infection; time-varying reproduction numbers of current variants and VOC; potential impact of community vaccinationGalloway et al.16
SIR model with compartments stratified by age, vaccine status, and infecting strainWashington, USAProject the timing and intensity of subsequent waves of infectionTime-varying, age-stratified effects of non-pharmaceutical interventions; different case thresholds for triggering and relaxing partial lockdowns; different vaccination rates and vaccine efficacy profiles; different infectivity rates of current variant and VOC B.1.1.7Reeves et al.17
An extended θ-SIR modelItalyAssess the impact of VOC B.1.1.7 and vaccination campaigns on spread of COVID-19Different numbers of SARS-CoV-2 variants and vaccines; time-varying reproduction numbers; differential immunity depending on dose of vaccineRamos et al.18
An extended SEIR model(“UVA PatchSim model”)Virginia, USAAssess the preliminary effect of vaccines and potential effect of new variants on the trajectory of casesSeasonal effects, including effect from pandemic fatigue; impact of VOC B.1.1.7; impact of community vaccinationUniversity of Virginia
Department of Health19
An extended SEIR model (“Behavioral SEIR”)USA; UKForecast the evolution of the epidemicSeasonal variation in transmission rate; pandemic fatigue; spread of the new variant (same seasonal pattern but different transmissibility)Atkeson20
An extended SEIR modelBrazilForecast disease transmission behaviour under 2 SARS-CoV-2 dominant strainsTime-varying reproduction numbers of the original SARS-Cov-2 D614 and its dominant G614 variant; different incubation ratesCelaschi21
Renewal equation based semi-mechanistic modelEnglandCompare reproduction numbers of VOC with non-VOCTime-varying reproduction numbers of current variants and VOC B.1.1.7; hotspots of infection; true positive rate adjusted SGTF frequencies (proxy for VOC frequencies)Volz et al.22
Age-structured SEIR modelIndiaAssess optimal vaccine allocation strategiesDifferent age-stratified vaccination strategies and rates; different efficacies and types of immunity from vaccinesFoy et al.25
  • Abbreviations: θ, instantaneous ratio of new detected infectious cases per unit time over the total; COVID-19, coronavirus disease; SARS-CoV-2, severe acute respiratory syndrome coronavirus-2; SEIR, susceptible-exposed-infected-recovered; SGTF, S-gene target failures; SIR, susceptible-infected-recovered; VOC, variant of concern.