Covid, Iss: “With vaccines 8 million infections and 150 thousand deaths avoided”

The anti-Covid vaccination campaign in Italy has made it possible to avoid “about 8 million cases, over 500 thousand hospitalizations, over 55 thousand hospitalizations in intensive care and about 150 thousand deaths”, of which more than 7 out of 10 in the elderly over 80. The estimate, which refers to the period between December 27, 2020, the ‘V-Day’ in which vaccinations began, and January 31, 2022, is contained in the report ‘Sars-CoV-2 infections, hospitalizations and deaths associated with Covid -19 directly avoided by vaccination ‘, published by the Higher Institute of Health. The calculation – explains the ISS – was made with a methodology initially developed for influenza vaccines, but already applied in other countries for studies relating to Sars-CoV-2, which uses data from the integrated surveillance and the national vaccine registry. of the Ministry of Health. This approach is based on the idea that the weekly impact of vaccination on the events studied (Covid-19 notified cases, hospitalizations, ICU admissions and deaths) can be estimated by combining vaccination efficacy towards the event of interest, coverage weekly vaccination and the weekly number of observed events. This estimate is called direct as it does not consider – the Institute specifies – the possible indirect impact of the same vaccination on the unvaccinated population: for example, the infections avoided among the vaccinated could have contained the overall transmissibility observed in Italy. From the beginning of the vaccination campaign to 31 December 2021 – the ISS details – it is estimated that a total of 2.8 million cases (range 2.8-3.4 million), 290 thousand hospitalizations have been avoided thanks to vaccination (218-400 thousand), 38 thousand hospitalizations in intensive care (27-54 thousand) and 78 thousand deaths (54-114 thousand). These figures represent respectively 43%, 58%, 57% and 64% of expected events, i.e. those observed plus those avoided. In January 2022 alone, characterized by the predominance of the highly diffusive Omicron variant, in which a total of 4.3 million diagnoses of Sars-CoV-2 infection were observed, vaccination made it possible to avoid a total of 5 , 2 million cases of infection (range 4.3-6.4 million), 228 thousand hospitalizations (161-384 thousand), 19 thousand hospitalizations in intensive care (13-31 thousand) and 74 thousand deaths (48-130 thousand). These figures represent respectively 55%, 83%, 86% and 87% of the events expected in January 2022. 72% of the overall deaths – still highlights the ISS – have been avoided for people of equal age. or over 80 years old, 19% in the 70-79 age group, 7% in the 60-69 age group and 3% under 60 years old. The distribution of avoided events was not homogeneous during the period studied, the Institute notes. In the first half of 2021, due to low vaccination coverage, the number of events avoided was limited. Instead, during the second half of 2021 and during January 2022, vaccination is estimated to have avoided more than half of the expected events.