SARS-CoV-2 specific serological pattern in healthcare workers of an Italian COVID-19 forefront hospital

Abstract

Background COVID-19 is an infectious disease caused by a novel coronavirus (SARS-CoV-2). The immunopathogenesis of the infection is currently unknown. Healthcare workers (HCWs) are at highest risk of infection and disease. Aim of the study was to assess the sero-prevalence of SARS-CoV-2 in an Italian cohort of HCWs exposed to COVID-19 patients. Methods A point-of-care lateral flow immunoassay (BioMedomics IgM-IgG Combined Antibody Rapid Test) was adopted to assess the prevalence of IgG and IgM against SARS-CoV-2. It was ethically approved (“Milano Area 1” Ethical Committee prot. n. 2020/ST/057). Results A total of 202 individuals (median age 45 years; 34.7% males) were retrospectively recruited in an Italian hospital (Milan, Italy). The percentage (95% CI) of recruited individuals with IgM and IgG were 14.4% (9.6–19.2%) and 7.4% (3.8–11.0%), respectively. IgM were more frequently found in males (24.3%), and in individuals aged 20–29 (25.9%) and 60–69 (30.4%) years. No relationship was found between exposure to COVID-19 patients and IgM and IgG positivity. Conclusions The present study did show a low prevalence of SARS-CoV-2 IgM in Italian HCWs. New studies are needed to assess the prevalence of SARS-CoV-2 antibodies in HCWs exposed to COVID-19 patients, as well the role of neutralizing antibodies.

Seroprevalence of SARS-CoV-2 antibodies among hospital workers in a German tertiary care center: A sequential follow-up study

“…These low overall infection rates are despite more than 170 patients with SARS-CoV-2 infections that had been treated at our center during the study period. Notwithstanding considerable exposure to COVID-19, infection rates in our study were substantially lower than in HCWs from Belgium (12.6%) ( Martin et al, 2020 ), Spain (11.2%) ( Garcia-Basteiro et al, 2020 ), Italy (14.4%) ( Sotgiu et al, 2020 ), Sweden (19.1%) ( Rudberg et al, 2020 ) the United Kingdom (10.8%–43.5%) ( Martin et al, 2020 ; Houlihan et al, 2020 ) and the United Stated of America (7.6%–13.7%) ( Moscola et al, 2020 ; Stubblefield et al, 2020 ). Those marked differences in infection rates may be partially explained by local differences in community transmission: population seroprevalence has been estimated to be 8.0% in Belgium, 5.5% in Spain, 4.6% in Italy, 3.7% in Sweden, 5.1% in the United Kingdom, and only 0.85% in Germany by May 2020 ( Flaxman et al, 2020 ).…”

“…This approach is paramount to evaluate and adjust infection control measures to mitigate nosocomial transmission of SARS-CoV-2. By now, several studies have demonstrated high seroprevalence in HCWs in countries most affected by COVID-19 ( Garcia-Basteiro et al, 2020 ; Sotgiu et al, 2020 ; Rudberg et al, 2020 ; Houlihan et al, 2020 ; Martin et al, 2020 ; Moscola et al, 2020 ; Stubblefield et al, 2020 ) but data from German HCWs are scarce ( Korth et al, 2020 ). By 17th July 2020, a total of 5232 cases had been confirmed amongst the 1.9 million inhabitants of the city of Hamburg, which constituted one of the highest infection rates in Germany ( Robert Koch Institute, 2020 ).…”

The Many Faces of Covid-19 at a Glance: A University Hospital Multidisciplinary Account From Milan, Italy

“…This the approach adopted by our Occupational Health Unit during the so called “second wave” of the epidemics. A serologic retrospective study in in healthcare workers in our hospital revealed that individuals with IgM and IgG were 14.4 and 7.4%, respectively with no relationship was between exposure to Covid-19 patients and serological status ( 39 ).…”

Source and symptoms of COVID-19 among hospital workers in Milan

“…A recent review article on asymptomatic COVID-19 transmission underlined this risk in the healthcare setting, although concentrating on the risk arising from asymptomatic patients [ 20 ]. A recent study has revealed that apparently healthy HCWs might have developed IgG and IgM antibodies, although no association with being exposed to COVID-19 patients was found [ 21 ]. These results indicate that relying on symptoms might not be an optimal strategy, and our results put the focus on source control.…”