Profiling Antibody Response Patterns in COVID-19: Spike S1-Reactive IgA Signature in the Evolution of SARS-CoV-2 Infection.

This contribution explores in a new statistical perspective the antibody responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 141 coronavirus disease 2019 (COVID-19) patients exhibiting a broad range of clinical manifestations. This cohort accurately reflects the characteristics of the first wave of the SARS-CoV-2 pandemic in Italy. We determined the IgM, IgA, and IgG levels towards SARS-CoV-2 S1, S2, and NP antigens, evaluating their neutralizing activity and relationship with clinical signatures. Moreover, we longitudinally followed 72 patients up to 9 months postsymptoms onset to study the persistence of the levels of antibodies. Our results showed that the majority of COVID-19 patients developed an early virus-specific antibody response. The magnitude and the neutralizing properties of the response were heterogeneous regardless of the severity of the disease. Antibody levels dropped over time, even though spike reactive IgG and IgA were still detectable up to 9 months. Early baseline antibody levels were key drivers of the subsequent antibody production and the long-lasting protection against SARS-CoV-2. Importantly, we identified anti-S1 IgA as a good surrogate marker to predict the clinical course of COVID-19. Characterizing the antibody response after SARS-CoV-2 infection is relevant for the early clinical management of patients as soon as they are diagnosed and for implementing the current vaccination strategies.

[A proposal for the management of health surveillance and monitoring procedures in relation to the risks posed by SARS-COV-2 to hospital and nursing home workers, based on strategies implemented in the facilities of the Fondazione Opera San Camillo]. / Proposta per la gestione delle attività di sorveglianza sanitaria e monitoraggio in relazione al rischio SARS-CoV-2 in operatori di strutture sanitarie ospedaliere e socioassistenziali sulla base dell'esperienza condotta nelle strutture della Fondazione Opera San Camillo.

SUMMARY: This paper describes how the health surveillance protocols adopted in hospitals and nursing homes have changed in response to the spread of SARS-CoV-2 and its risks. These changes concern assessments that must be performed with urgency, to detect potential cases and symptoms that may indicate contagion and to protect vulnerable and hypersensitive workers. Besides, these changes have been implemented in order to regulate how the appointed occupational physician should perform everyday tasks, particularly in regard to preventive visits, periodic visits, office visits, and visits meant to authorize one's return to the workplace. This paper recommends that both preventive visits and periodic visits should include rapid antigen swab tests to screen for SARS-CoV-2 (which, if positive, should be confirmed by molecular tests) and serologic tests to detect IgG SARS-CoV-2 antibodies. Since this phase involves great risks for healthcare facilities, this paper proposes that swab testing should be performed every month and that serologic testing should be performed every three months (depending on whether the first test detects the presence of IgG antibodies). By combining antigen and molecular swab tests, healthcare professionals can diagnose workers with SARS-CoV-2 and identify positive asymptomatic cases. Because of its costs and its long turnaround times for results, molecular swab testing is recommended only when one needs to confirm a positive antigen swab test result. Serologic testing should be used alongside swab testing, to acquire data concerning the immunity of workers.