COVID-19 severity appears to be reduced in spring/summer.

BACKGROUND: because of different human behaviours, SARS-CoV-2 spread may be lower in spring/summer. On the contrary, it is not clearly known whether the clinical course/severity of hospitalized patients infected by SARS-CoV-2 can be different in the various seasons.. OBJECTIVES: to understand whether there were differences in severity of COVID-19 in patients who had contracted the infection in winter versus those infected in spring/summer. DESIGN: observational retrospective cohort study. SETTING AND PARTICIPANTS: from the administrative database of the SARS-CoV-2 surveillance system and that of hospital discharge, a cohort of patients (8,221, 653 of which were hospitalized) who tested positive to the RT-PCR test for SARS-CoV-2 between 01.12.2020 and 31.07.2021 in the Grosseto province (Tuscany Region, Central Italy) was selected and analysed. MAIN OUTCOME MEASURES: hospitalization rate and length, continuous positive airway pressure (CPAP) or non-invasive ventilation (NIV) use, Intensive Care Unite (ICU) admissions, intra-hospital mortality and PaO2/FiO2 values were measured and compared between subjects infected in winter and those who developed COVID-19 in spring/summer. Viral load (cycle threshold, Ct), vitamin D, serum ferritin, IL-6, procalcitonin, D-dimer, and C-reactive protein measured in the two periods were also compared. RESULTS: in the considered months, the hospitalization rate among 8,221 patients with COVID-19 was 8%: 370 (8.5%) individuals were hospitalized in winter and 283 (7,3%; p=0.31) in spring/summer; 62 (16.8%), 88 (23.8%), and 63 (17%) in winter and 28 (9.9%), 40 (14.1%), and 36 (12.7%) in spring/summer were admitted in ICU (p=0.01), used CPAP/NIV (p=0.002) and died (p=0.13), respectively. Hospitalization days were 14.5±11.6 in winter and 10.3±8.84 in spring/summer (p=0.001), while minimum PaO2/FiO2, measured during hospital stays was 123.2±38.6 in spring/summer and 112.6±40.8 in winter (p=0.054). Multivariate analysis (adjusted for all confounding factors) also confirmed reduced risks of having ICU admissions (0.53; 95%CI 0.32;0.88; p=0.01) and of using CPAP/NIV (0.48; 95%CI 0.32;0.75; p=0.001) in spring/summer when compared to winter. Hospitalization days and minimum PaO2/FiO2 were also lower in spring/summer (ß= -3.9; 95%CI -5.5;-2.2; p=0.001) and winter (ß= -17; 95%CI -0.93;35; p=0.06), respectively. The adjusted hazard ratio of mortality in winter, obtained with a Cox model, was higher of about 38% compared to spring/summer. No Ct values (viral load) differences were found either in winter (19.45±6.18) or spring/summer (20.3±6.7; p=0.343). IL-6, ferritin, procalcitonin, D-dimer were similar. Conversely, CRP was lower whereas vitamin D was higher in the warmer seasons. CONCLUSIONS: COVID-19 may be less severe during spring/summer in hospitalized patients. This does not seem to be influenced by different SARS-CoV-2 viral load in the different periods considered. C-reactive protein was found to be lower whereas vitamin D higher in the warmer months. It can be hypothesized that higher levels of vitamin D in spring/summer, compared to winter, may be associated to a positive modulation of COVID-19 induced inflammation with a possible disease severity reduction during spring/summer.

Spontaneous abdominal bleeding associated with SARS-CoV-2 infection: causality or coincidence?

Authors present 6 cases of abdominal bleeding associated with COVID-19, representing 1.35% of all hospitalized COVID-19 patients and hypothesize that there could be, although not very frequently, a relationship between SARS-CoV2 and bleeding. They excluded a side effect of the low molecular weight heparin therapy that all patients underwent during the course of the disease or other possible causes. Alterations of the coagulation state or a weakness of the vascular wall due toa presumed endotheliitis SARS-CoV-2 infection induced, are hypothesized by the authors. Investigation and follow-up for possible hemorrhagic problems in patients with COVID-19 is recommended. In particular, clinicians should be vigilant about retroperitoneal hemorrhage in COVID-19 patients. In addition to the fact that these patients are being treated with anticoagulants, anemia and abdominal pain are the signs that should lead us to suspect this type of haemorrhage. More studies are needed to understand if COVID-19 can be directly associated with bleeding. (www.actabiomedica.it)

Circulating Vitamin D levels status and clinical prognostic indices in COVID-19 patients.

BACKGROUND: Several immune mechanisms activate in COVID-19 pathogenesis. Usually, coronavirus infection is characterized by dysregulated host immune responses, interleukine-6 increase, hyper-activation of cytotoxic CD8 T lymphocytes. Interestingly, Vitamin D deficiency has been often associated with altered immune responses and infections. In the present study, we evaluated Vitamin D plasma levels in patients affected with different lung involvement during COVID-19 infection. METHODS: Lymphocyte phenotypes were assessed by flow cytometry. Thoracic CT scan involvement was obtained by an image analysis program. RESULTS: Vitamin D levels were deficient in (80%) of patients, insufficient in (6.5%) and normal in (13.5%). Patients with very low Vitamin D plasma levels had more elevated D-Dimer values, a more elevated B lymphocyte cell count, a reduction of CD8 + T lymphocytes with a low CD4/CD8 ratio, more compromised clinical findings (measured by LIPI and SOFA scores) and thoracic CT scan involvement. CONCLUSIONS: Vitamin D deficiency is associated with compromised inflammatory responses and higher pulmonary involvement in COVID-19 affected patients. Vitamin D assessment, during COVID-19 infection, could be a useful analysis for possible therapeutic interventions. TRIAL REGISTRATION: 'retrospectively registered'.

Why do children seem to be more protected against COVID-19? A hypothesis.

Today it remains unclear why children seem to be less likely to get infected by COVID-19 or why they appear to be less symptomatic after infections. All individuals, especially children, are exposed to various viruses including human coronavirus (CoVs) that can generally lead to respiratory infections. We hypothesize that recurrent CoVs exposure may induce an effective antiviral B and T-cell-mediated adaptive immune response, which could also be protective against COVID-19. Based on the high-homology between the Spike protein epitopes of taxonomically-related coronaviruses, we theorize that past/recurrent contact with CoVs might shield children also against the circulating COVID-19 through a possible neutralizing antibody response previously CoVs-induced. This would open up possible lines of research for the development of live-attenuated virus vaccines from CoVs. Future research is desirable to confirm or disprove such hypothesis.