**1. Introduction**

The novel coronavirus (SARS-CoV-2), the causative agen<sup>t</sup> of Corona Virus Disease-2019 (COVID-19), is the most severe global public health emergency of the twenty-first century [1].

The disease, which appeared in Wuhan, China, in December 2019, quickly spread across continents and was declared a pandemic by the World Health Organization (WHO) on 11 March 2020 [2].

At 5 February 2021, SARS-CoV-2 has infected over 104,000,000 persons and caused over 2,200,000 deaths globally [2].

Current information suggests that, in community settings, person-to-person transmission most commonly occurs via the respiratory droplets of the infected individual (through coughing, sneezing, talking, etc.), close interaction with the infected person, or self-delivery of the microorganism to the eyes, nose, or mouth via SARS-CoV-2 contaminated hands [3].

In health care scenarios, in addition to respiratory droplet-borne or contact-borne transmission, airborne transmission can also occur via aerosol-generating operations [3].

SARS-CoV-2 is highly transmissible, and health care workers (HCWs) have been occupied with the important risk of providing care to supposed or confirmed COVID-19 cases. Some reports have shown that numerous HCWs have contracted COVID-19 in health care settings globally [4–8].

The WHO, the Center for Disease Control and Prevention (CDC), and the European Centre for Disease Prevention and Control (ECDC) issued procedures for COVID-19

**Citation:** Ledda, C.; Carrasi, F.; Longombardo, M.T.; Paravizzini, G.; Rapisarda, V. SARS-CoV-2 Seroprevalence Post-First Wave among Primary Care Physicians in Catania (Italy). *Trop. Med. Infect. Dis.* **2021**, *6*, 21. https://doi.org/10.3390/ tropicalmed6010021

Received: 9 January 2021 Accepted: 7 February 2021 Published: 9 February 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

managemen<sup>t</sup> that endorse safety protocols for HCWs, such as using appropriate personal protective equipment (PPE).

Nevertheless, because the suggested infection control protections have not been adequate to prevent the spread of the SARS-CoV-2 infection among HCWs, unrecognized risk factors may contribute to the transmission of viruses in hospitals [4–8].

However, not all healthcare is provided in a hospital setting. In particular, family physicians or pediatricians and general practitioners (GPs) work in a setting away from the hospital.

GPs usually visit numerous patients, frequently at their homes, with low potential, if any, to control the work setting. Particularly during the initial phases of the COVID-19 outbreak, GPs were not informed of the occurrence of SARS-CoV-2-infected patients, with inadequate information about the risk, a lack of suitable protective measures and, in some cases, deficient or poor accessibility to PPE [9].

Modenese and Gobba reported that 44% of the COVID-19 related deaths among Italian physicians were GPs [10].

In Italy, the first wave started at the end of January 2020 and in March, the governmen<sup>t</sup> implemented a series of restrictive measures. On March 5th, all schools and universities in Italy locked their buildings to scholars. From 8 March to 4 May, the population was forced to respect the lockdown.

In the province of Catania, 777 cases [11] of COVID-19 were reported until the end of June, that is, the period of the effect of the lockdown.

The present study aims to estimate the seroprevalence of SARS-CoV-2 in a cohort of GPs working in Catania (Italy) after the first wave of COVID-19.

#### **2. Materials and Methods**

In the province of Catania, there are approximately 1100 working GPs. From June to July 2020, GPs working in the province of Catania (Italy) were recruited in this study through contacts made via mail from a GP database obtained from the Medical Board.

The GPs who made themselves available to participate in the study were contacted by email and filled out an online form that included the registration of: personal and work data, number of patients with COVID-19, any previous diagnosis of COVID-19 through molecular swab, eventual close contact with cases of COVID-19, possible presence of symptoms of COVID-19 attributable to contact, presence of other pathologies.

Following the receipt of answers from the GPs, blood sampling sessions were organized, two at the University of Occupational Medicine, and four in the province. The collected serum was immediately taken to the laboratory and analyzed the same day.

Serological analysis was performed using The NovaLisa® SARS-CoV-2 IgG (NovaTec Immundiagnostics GmbH, Dietzenbach, Germany) ELISA method. The aim of the test was the qualitative detection of IgG antibodies to SARS-CoV-2 virus in human serum.

Informed consent was obtained from all GPs. The present study was approved by the ethics committee of Catania University Hospital (n. 54/2020).

Data were analyzed with the software SPSS 22.0 (SPSS Inc., Chicago, IL, USA) for Windows. Descriptive analyses were performed using frequency percentages and mean and standard deviation.
