The article "Modeling vaccination rollouts, SARS-CoV-2 variants and the requirement for non-pharmaceutical interventions in Italy" has been published on Nature Medicine. Among the authors of the study there are Patrizio Colaneri and Paolo Bolzern of Dipartimento di Elettronica. Informazione e Bioingegneria (Politecnico di Milano).

The research evaluates the impact of the vaccination campaign on the future evolution of the epidemic, in the presence of various containment measures that impose precautions and rules of social distancing and SARS-CoV-2 variants of concern. To quantitatively evaluate the possible scenarios, the authors combined their epidemiological model (already published on Nature Medicine in April 2020) with a new health care cost model based on second wave data.

The study shows that, despite the start of the mass vaccination campaign, containment measures remain crucial to controlling the epidemic, partly due to the circulation of highly transmissible variants of SARS-CoV-2. The adoption of harsher restrictions slows transmission more than rapid vaccine administration, while the easing of containment measures leads to a surge in cases of infection, requiring new closures, resulting in cycles of intermittent restrictions. Preemptive strategies (first closing, then opening when the number of cases has dropped sufficiently) could drastically reduce hospitalizations and deaths, without aggravating socio-economic costs, compared to a late intervention (first opening, then closing only shortly before the saturation of ICUs). As with any study based on mathematical models, there are inherent limitations: although the scenarios are outlined on the basis of reasonable assumptions, the future evolution of the epidemic will depend on the measures actually taken and the speed of vaccination, as well as the possible emergence of other variants.

The research results constitute a strong argument in support of the need to maintain containment measures in the first phase of the vaccination campaign until sufficient population immunity is achieved. They also show the effectiveness of preemptive action: when closing/opening intervals alternate, if, instead of starting with an opening period, one would start with a closing period, tens of thousands of lives would be saved and health costs would be drastically reduced. Since it is only a question of exchanging the order of the closing and opening periods and not their duration, these savings would occur without any increase in socio-economic costs.