ISS, August 2nd 2021
The measures introduced last autumn with the Decree of the President of the Council of Ministers of 3 November 2020 to mitigate the COVID-19 epidemic in Italy reduced the transmissibility (RT) of the SARS-COV-2 virus by 13-19% in the Yellow Zone, by 27-38% in the Orange Zone and by 36-45% in the Red Zone. These findings are the main results of a joint study carried out by the Bruno Kessler Foundation, the Istituto Superiore di Sanità – ISS (Italian National Institute of Health) and INAIL which was published in the journal Nature Communications.
The study shows that the Yellow Zone was effective in stabilizing the incidence of cases, bringing the RT to values close to 1, while the Orange and Red Zones produced a substantial reduction in incidence by lowering the RT to values between 0.80 and 0.93 in the Orange Zone and between 0.74 and 0.83 respectively. Overall, the measures brought the epidemic back under control in 85 out of 107 Provinces within 3 weeks of their introduction, avoiding a total of approximately 25,000 hospitalizations over the same period, that is to say more than half the number of hospitalized individuals who were 44,000 at the time. The positive effects on the reduction of hospitalizations, however, are even more significant if observed over a longer period, thanks to the decline in the incidence of infections resulting from the measures adopted.
For the research, data from the Integrated Surveillance System and data on public mobility were used. These data were processed by using mathematical models to quantify the association between the measures and the change in R (t) between the week of October 30 - 5 November, before the introduction of the' Zones', and the week from 19 to – 25 November, when the effects could be considered stabilized.
The study also highlighted that even the Zones with the more stringent restrictions had a significantly lower reduction in social activities compared to the lockdown of spring 2020: for example, compared to an average time spent at home by Italians of about 16 hours a day
in the pre-pandemic period (ISTAT data), for the Red Zones the estimated time spent at home was 18.7 hours a day against about 20.3 during the lockdown.
