Burden of SARS-CoV-2 Infection in Populations With High or Low Risk of Infection

SARS-CoV-2 infection currently affects more than two million people worldwide and has caused the death of more than 150,000 people. In Lombardia there were 64.000 confirmed positive subjects (64:10,000) and 12,000 dead, with a large number of healthcare workers (HCWs) involved. However, the number of recovered is starting to rise and, thanks to the containment measures introduced, the number of new cases per day is falling. However, the situation is quite different in other part of Italy; f.i. in Molise, a southern Italy region, there is a much lower incidence of positivity and mortality: 269 confirmed positive (9:10,000) and 16 deaths.

To plan the second phase of outbreak management, waiting for the development of a vaccine and valid therapeutic tools, preventive interventions should be revisited based on evidence from the literature and from local epidemiological data. However, although the infection is now worldwide spread, some issues are still not known.

The actual number of subjects with an active or past SARS-CoV-2 infection is not known, since the approach used was based on tests performed in severe cases and in their contacts, while few investigations have been carried out on the general population. The impact of the emergency on the health of both HCWs or general population is not yet known. Furthermore, the reasons for the different spread of the infection in the North and South of the country, as well as the different characteristics of the subjects who have or have had the infection with respect to those who have not had it are not yet fully known; moreover, among the positive ones, the characteristics associated with the development of the more serious forms or the absence of symptoms, remain to be elucidated. In fact, the studies conducted so far were large studies that collected few data or were more detailed studies focused only on few hospitalized subjects.

It is therefore necessary to conduct new studies on the general population, based on large samples randomly selected from populations at high and low spread of the infection as well as in subgroups at higher risk such as HCWs, and based on a large set of collected data. The aims of this project are: (i) to estimate the real prevalence of the SARS-CoV-2 infection and seroconversion in two populations at high and low risk of infection, in a comparative way, from the territories of ASST Sette Laghi of Varese, Lombardia region (confirmed cases 18:10,000) and a region at lower prevalence of confirmed cases such as the Molise region (confirmed cases 9:10,000 subjects), also focusing on subgroups at higher risk such as healthcare workers (HCWs); (ii) to estimate the rate of burnout and post-traumatic stress disorder in HCWs during the study period; (iii) to identify factors associated with SARS-CoV-2 infection positivity and follow up at mead-term its effect on health.

Finally, the investigators will biobank biological samples for future studies, in already available specialized facilities.