Effects of environmental parameters and their interactions on the spreading of SARS-CoV-2 in North Italy under different social restrictions. A new approach based on multivariate analysis

Abstract

In 2020 North Italy suffered the SARS-CoV-2-related pandemic with a high number of deaths and hospitalization. The effect of atmospheric parameters on the amount of hospital admissions (temperature, solar radiation, particulate matter, relative humidity and wind speed) is studied through about 8 months (May–December). Two periods are considered depending on different conditions: a) low incidence of COVID-19 and very few regulations concerning personal mobility and protection (“free/summer period”); b) increasing incidence of disease, social restrictions and use of personal protections (“confined/autumn period”). The “hospitalized people in medical area wards/100000 residents” was used as a reliable measure of COVID-19 spreading and load on the sanitary system. We developed a chemometric approach (multiple linear regression analysis) using the daily incidence of hospitalizations as a function of the single independent variables and of their products (interactions). Eight administrative domains were considered (altogether 26 million inhabitants) to account for relatively homogeneous territorial and social conditions. The obtained models very significantly match the daily variation of hospitalizations, during the two periods. Under the confined/autumn period, the effect of non-pharmacologic measures (social distances, personal protection, etc.) possibly attenuates the virus diffusion despite environmental factors. On the contrary, in the free/summer conditions the effects of atmospheric parameters are very significant through all the areas. Particulate matter matches the growth of hospitalizations in areas with low chronic particulate pollution. Fewer hospitalizations strongly correspond to higher temperature and solar radiation. Relative humidity plays the same role, but with a lesser extent. The interaction between solar radiation and high temperature is also highly significant and represents surprising evidence. The solar radiation alone and combined with high temperature exert an anti-SARS-CoV-2 effect, via both the direct inactivation of virions and the stimulation of vitamin D synthesis, improving immune system function.

SARS-CoV-2 infection in animals: Patterns, transmission routes, and drivers

“…Solar irradiance can also limit the spread of SARS-CoV-2, with fewer cases reported in regions with higher temperatures and stronger solar radiation [ 34 ]. While the number of cases exhibits a weakly positive correlation with barometric pressure, precipitation, diurnal temperature, sulfur dioxide, and ozone [ 35 ], wind speed is rarely significantly associated with the number of infected people, with exceptions such as decreased numbers during intense windy days [ 36 , 37 ].…”

Environmental factors are associated to hospital outcomes in COVID-19 patients during lockdown and post-lockdown in 2020: A nationwide study

“…Those studies have initially established relationships between air pollutants and COVID- 19 transmission, particularly PM 2 . 5 ( Wang et al, 2020 ; Tateo et al, 2022 ), but also PM 10 , CO, NO 2 , and O 3 ( Zhu et al, 2020 ; Copat et al, 2020 ). Many mortality studies have been performed worldwide ( Bozack et al, 2022 ; Coker et al, 2020 ; Hendryx and Luo, 2020 ; Wu et al, 2020 ), but only a few studies contemplating a short term analysis ( Jiang and Xu, 2021 ; Khorsandi et al, 2021 ).…”

Characteristics, comorbidities and laboratory measures associated with disease severity and poor prognosis in young and elderly patients with COVID-19 admitted to medical wards in Emilia-Romagna region, Italy: a multicentre retrospective study

“…The entire dataset ranged from 8 to 6238 ng/ml. Nevertheless, several studies have explored ferritin as a potential target for the treatment of COVID-19 and, 66 iii) In March 2020, since the earliest phases of SARS-CoV-2 pandemic outbreak, the rationale for a possible protective and therapeutic role of vitamin D and other micronutrients was proposed by Fiorino and other authors, 5,25,32,68 on the basis of the possible ability of some fat-soluble compounds, in modulating directly or indirectly the replication of SARS-CoV-2, in regulating host's immune activity against this pathogen and, probably, in improving his response to vaccination. 69 Since then, a large series of retrospective and prospective trials and systematic reviews have been carried out in patients suffering from COVID-19 with the aim to assess the potential association between their vitamin D levels and their disease outcome as well as the impact of vitamin D supplementation on their prognosis.…”

“…Immune-compromised patients, such as individuals with cancer or with persistent pathological conditions, as well as elderly subjects with several diseases, including diabetes, hypertension, cardiovascular disease, obesity, autoimmune diseases, chronic kidney/lung/liver diseases, dementia, solid organ transplant 22,23 are at higher risk to develop severe forms of COVID-19 with a potentially poor outcome in comparison to younger and healthier individuals. 24,25 SARS-CoV-2 infection may cause an impairment in the function of kidney and gastrointestinal tract, mainly in elderly people, [26][27] inducing fluid and electrolyte imbalances (such as hyper/hyponatremia, hypokalemia, hypocalcemia) in those subjects who undergo a higher probability of complications and even a more elevated risk of death. [28][29][30][31] Furthermore, it has been suggested that low levels of vitamin D are associated with an increased risk of SARS-CoV-2 infection and a poorer prognosis in patients with deficiency of this micronutrient, but to date, no definitive results have been yet obtained.…”