Mitigation and herd immunity strategy for COVID-19 is likely to fail

Wolfgang Bock; Barbara Adamik; Marek Bawiec; Viktor Bezborodov; Marcin Bodych; Jan Pablo Burgard; Thomas Goetz; Tyll Krueger; Agata Migalska; Barbara Pabjan; Tomasz Ozanski; Ewaryst Rafajlowicz; Wojciech Rafajlowicz,; Ewa Skubalska-Rafajlowicz; Sara Ryfczynska; Ewa Szczurek; Piotr Szymanski

stays overcritical but below the capacity limit of the health care system to reach herd immunity is so narrow that a successful implementation of this strategy is likely to fail. Our microsimulation is based on official census data and involves household composition and age distribution as the main population structure variables. Outside household contacts are characterised by an out-reproduction number R* which is the only free parameter of the model. For a subcritical domain we compute the time till extinction and prevalence as a function of the initial number of infected individuals and R*. For the Polish city of Wroc law we also discuss the combined impact of testing coverage and contact reduction. For both countries we estimate R* for disease progression until 20th of March 2020.