Despite progress in clinical care for patients with coronavirus disease 2019 (COVID-19), population-wide interventions are still crucial to manage the pandemic, which has been aggravated by the emergence of new, highly transmissible variants.

In this study, we combined the SIDARTHE model, which predicts the spread of SARS-CoV-2 infections, with a new
data-based model that projects new cases onto casualties and healthcare system costs.

Based on the Italian case study, were outlined several scenarios: mass vaccination campaigns with different paces, different transmission rates due to new variants and different enforced countermeasures, including the alternation of opening and closure phases.

Results, published on Nature Medicine, demonstrate that non-pharmaceutical interventions (NPIs) have a higher effect on the epidemic evolution than vaccination alone, advocating for the need to keep NPIs in place during the first phase of the vaccination campaign.

Model predicts that, from April 2021 to January 2022, in a scenario with no vaccine rollout and weak NPIs (R0 = 1.27), as many as 298,000 deaths associated with COVID-19 could occur. However, fast vaccination rollouts could reduce mortality to as few as 51,000 deaths.

Implementation of restrictive NPIs (R0 = 0.9) could reduce COVID-19 deaths to 30,000 without vaccinating the population and to 18,000 with a fast rollout of vaccines.

It’s also shown that, if intermittent open–close strategies are adopted, implementing a closing phase first could
reduce deaths (from 47,000 to 27,000 with slow vaccine rollout) and healthcare system costs, without substantive aggravation of socioeconomic losses.