Effectiveness of infection-containment measures on SARS-CoV-2 seroprevalence and circulation from May to July 2020, in Milan, Italy

Abstract

Objective Through a hospital-based SARS-CoV-2 molecular and serological screening, we evaluated the effectiveness of two months of lockdown and two of surveillance, in Milan, Lombardy, the first to be overwhelmed by COVID-19 pandemics during March-April 2020. Methods All subjects presenting at the major hospital of Milan from May-11 to July-5, 2020, underwent a serological screening by chemiluminescent assays. Those admitted were further tested by RT-PCR. Results The cumulative anti-N IgG seroprevalence in the 2753 subjects analyzed was of 5.1% (95%CI = 4.3%-6.0%), with a peak of 8.4% (6.1%-11.4%) 60–63 days since the peak of diagnoses (March-20). 31/106 (29.2%) anti-N reactive subjects had anti-S1/S2 titers >80 AU/mL. Being tested from May-18 to June-5, or residing in the provinces with higher SARS-CoV-2 circulation, were positively and independently associated with anti-N IgG reactivity (OR [95%CI]: 2.179[1.455–3.264] and 3.127[1.18–8.29], respectively). In the 18 RT-PCR positive, symptomatic subjects, anti-N seroprevalence was 33.3% (95% CI: 14.8%-56.3%). Conclusion SARS-CoV-2 seroprevalence in Milan is low, and in a downward trend after only 60–63 days since the peak of diagnoses. Italian confinement measures were effective, but the risk of contagion remains concrete. In hospital-settings, the performance of molecular and serological screenings upon admission remains highly advisable.

SARS-CoV-2 Infection among the Dental Staff from Lombardy Region, Italy

“…This rate is higher than the global pooled estimate obtained by a systematic review among healthcare workers (pooled seroprevalence of SARS-CoV-2 antibody test: 7%) [ 14 ]. Our findings are also comparable with estimates found for the general population of Lombardy region [ 22 , 23 ]…”

“…The aim of this study is to quantify the SARS-CoV-2 antibody prevalence and determinants of a sample of dentists, dental hygienist, and other personnel working in dental setting from Lombardy region, where the prevalence of SARS-CoV-2 infection in the general population has been found to be relatively high—approximately 5–11% [ 22 , 23 ], with selected areas showing even higher prevalence of infection—up to 39% in Bergamo [ 24 ].…”

Seroprevalence of SARS-CoV-2 Antibodies in Adults and Healthcare Workers in Southern Italy

“…Despite these measures, the number of COVID-19 cases and deaths has increased dramatically and, to the best of our knowledge, up to date information on the proportion of subjects that have been infected and have produced antibodies against SARS-CoV-2 in Southern Italy is lacking [ 21 , 22 , 23 , 24 , 25 ], and it is reasonable to presume that a larger proportion of the population has been infected.…”

French Pediatric Societies Call for School to Stay Open amid the Coronavirus Disease 2019 Pandemic

“…A comparative study performed between March-May 2020 in Finland, where schools were closed, and Sweden, where schools remained open, showed no difference in incidence of infection and hospitalisations or deaths in <20 years old subjects 27 . In Italy, reports indicate that school does not act as an amplifier for transmission of SARS-CoV-2 and other settings where young people typically congregate were identified as a greater carrier of transmission 2 28 .…”