Antonini Chiara, Calandrini Sara, Bianconi Fortunato
ICT4life Srl, Via Mario Donati Guerrieri, 16, 06132 Perugia, Italy.
Department of Engineering, University of Perugia, Via Goffredo Duranti, 93, 06125 Perugia, Italy.
Vaccines (Basel). 2021 Aug 17;9(8):915. doi: 10.3390/vaccines9080915.
From the end of 2020, different vaccines against COVID-19 have been approved, offering a glimmer of hope and relief worldwide. However, in late 2020, new cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started to re-surge, worsened by the emergence of highly infectious variants. To study this scenario, we extend the Susceptible-Exposed-Infectious-Removed model with lockdown measures used in our previous work with the inclusion of new lineages and mass vaccination campaign. We estimate model parameters using the Bayesian method Conditional Robust Calibration in two case studies: Italy and the Umbria region, the Italian region being worse affected by the emergence of variants. We then use the model to explore the dynamics of COVID-19, given different vaccination paces and a policy of gradual reopening. Our findings confirm the higher reproduction number of Umbria and the increase of transmission parameters due to the presence of new variants. The results illustrate the importance of preserving population-wide interventions, especially during the beginning of vaccination. Finally, under the hypothesis of waning immunity, the predictions show that a seasonal vaccination with a constant rate would probably be necessary to control the epidemic.
从2020年底开始，多种针对2019冠状病毒病（COVID-19）的疫苗获得批准，给全球带来了一线希望和缓解。然而，在2020年末，严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的新病例开始再次激增，高传染性变种的出现使情况更加恶化。为了研究这种情况，我们扩展了之前工作中使用的带有封锁措施的易感-暴露-感染-康复模型，纳入了新的谱系和大规模疫苗接种活动。我们在意大利和翁布里亚地区这两个案例研究中，使用贝叶斯方法条件稳健校准来估计模型参数，意大利地区受变种出现的影响更为严重。然后，我们使用该模型来探索在不同疫苗接种速度和逐步重新开放政策下COVID-19的动态变化。我们的研究结果证实了翁布里亚地区较高的繁殖数以及由于新变种的存在导致传播参数的增加。结果表明了保持全人群干预措施的重要性，特别是在疫苗接种初期。最后，在免疫减弱的假设下，预测结果显示可能需要以恒定速率进行季节性疫苗接种来控制疫情。
