Covid‑19 in Northern Italy: An integrative overview of factors possibly influencing the sharp increase of the outbreak (Review)

Italy is currently one of the countries seriously affected by the COVID-19 pandemic. As per 10 April 2020, 147,577 people were found positive in a total of 906,864 tests performed and 18,849 people lost their lives. Among all cases, 70.2% of positive, and 79.4% of deaths occurred in the provinces of Northern Italy (Lombardi, Emilia Romagna, Veneto and Piemonte), where the outbreak first started. Originally, it was considered that the high number of positive cases and deaths in Italy resulted from COVID-19 initially coming to Italy from China, its presumed country of origin. However, an analysis of the factors that played a role in the extent of this outbreak is needed. Evaluating which factors could be specific for a country and which might contribute the most is nevertheless complex, with accompanying high uncertainty. The purpose of this work is to discuss some of the possible contributing factors and their possible role in the relatively high infection and death rates in Northern Italy compared to other areas and countries.