SARS-CoV-2 infection: use and effectiveness of antigenic swab for the health surveillance of healthcare workers.

BACKGROUND:  The gold standard to identify SARS-CoV-2 infections is the Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) on rhino-pharyngeal swabs, but faster and cheaper methods such as antigenic swabs have been developed. A retrospective observational study on antigenic swabs included in the extraordinary health surveillance protocol of a large Hospital in Turin was aimed to assess their performance validity. Methods: From 30 October 2020 to 4 May 2021, 4000 antigenic swabs were carried out in three groups of healthcare workers (HCWs), respectively (i) asymptomatic, (ii) cohabiting with a positive case, and (iii) not recently exposed to the virus.  Results: Overall sensitivity and specificity associated with a prevalence of 1.30% were 26.9%, 97.2%, respectively, the corresponding positive (PPV) and negative predictive value (NPV) being 11.29% and 99.02% [95% IC (99.00 - 99.04)] respectively; a prevalence of 0.29% was observed in the asymptomatic group, among whom sensitivity and specificity were 25.0% and 98.9%, respectively, the corresponding PPV and NPV being 6.25% and 99.78% [95% IC (99.76 - 99.81)], respectively; the cohabitant group showed a prevalence of 21.11%, sensitivity and specificity were 47.4%, 81.7%, respectively, giving rise to a PPV of 40.91% and NPV of 85.29% [95% IC (85.18 - 85.41)] respectively. The prevalence in the not exposed group was 0.77%, sensitivity and specificity were 29.2%, 97.4%, respectively, and PPV and NPV 8.05% and 99.44% [95% IC (99.42 - 99.46)] respectively. Conclusions: Antigenic swabs reduced costs and provided reliable diagnostic results. In the cohabitant group, the higher-prevalence groups showed poor test performances, likely because of the high prevalence of pre-symptomatic illness in this group. Owing to the relatively low NPV, a negative result would still require confirmation with a molecular test to be acceptable for a surveillance program that effectively reduces the virus's intra-hospital spread.

SARS-CoV-2 infection: efficacy of extensive vaccination of the healthcare workforce in a large Italian hospital.

BACKGROUND: A prospective observational study involved 13,787 Health Care Workers (HCWs) of a large hospital to assess the effectiveness of a SARS-CoV-2 mRNA vaccine. METHODS: The daily incidence of infections was estimated from 1st October 2020 to 30th April 2021 and compared with that of the province of Turin (2.26 million). In the middle of this period, a mass vaccination began among HCW, and its effect was assessed. RESULTS: In the first half-period, 1,163 positive HCWs were observed, the average daily incidence rate per 100,000 being 79.58 (± 15.58; 95% CI) compared to 38.54 (± 5.96; 95% CI) in the general population (p<0.001). The vaccination campaign immunized 9,843 HCWs; among them, the average daily incidence was 14.23 (± 2.73; 95% CI) compared to 34.2 (± 2.95; 95% CI) in the province (p<0.001). Among fully vaccinated HCW, 59 cases were observed, giving rise to an incidence of 6.3 (± 2.66; 95% CI) much lower than in the province (p<0.001). In the second half of the observation period, the RR for HCWs compared to the province dropped from 2.07 (1.96 - 2.18; 95% CI; p<0.001) to 0.5 (0.42 - 0.58; 95% CI; p<0.001) and to 0.17 (0.13 - 0.22; 95% CI; p<0.001) for unvaccinated and vaccinated HCWs, respectively. The RR of vaccinate HCW was 0.43 (0.31 - 0.58; 95% CI; p<0.001) compared to unvaccinated. In the second half of the observation period, unvaccinated HCWs had a RR of 0.21 (0.18 - 0.25; 95% CI; p<0.001) as compared to the first one. A linear regression model (R2 = 0.87) showed that every percent increase in vaccinated HCWs lowered daily incidence by 0.94 (0.86 - 1.02; IC 95%; p<0.001). Vaccinated HCWs had a RR of 0.09 (0.07 - 0.12; 95% CI; p<0.001) compared to unvaccinated HCWs, which led to estimated effectiveness of the two-dose vaccine of 91 % (± 3 %; CI 95%) similar to that reported by the manufacturer.

[COVID-19 and work environment: legislative developments about the role of the occupational physician in the emergency management and in the SARS-CoV-2-related work accidents notification]. / COVID-19 e Ambienti di lavoro: recenti evoluzioni normative del ruolo del Medico Competente nella gestione dell'emergenza e nella denuncia dei casi di infortunio professionale legati all'infezione da SARS-CoV-2.

SUMMARY: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and its associated disease (COVID-19) represent a global health emergency that requires integrated and multidisciplinary intervention by international medical and scientific communities, in support of the national governments. In Italy many public health measures have been adopted to contain the transmission of the disease, which also involved occupational physicians. The regulatory path has had a rapid evolution due to the trend of infections and progressive scientific evidence: the most recent Circular from the Ministry of Labor and Social Policies and the Ministry of Health provides for the termination of the "exceptional health surveillance" activity, the management and protection of fragile individuals by activating the medical examination on request of the employee and excludes the old age, without comorbidities, as a specific condition of risk of serious complication of SARS-CoV-2 infection. For preventive and insurance purposes, COVID-19 usually represents a generic biological risk, for which the same measures must be adopted for the entire population. In the Inail Circular no. 13 of April 3, 2020, however, it is stated that professional categories that perform front office duties are considered exposed to a higher risk, as well as, health professionals, can be considered exposed to a specific risk. From January 1st to July 31st 2020, 51,363 cases of infection from SARS-CoV-2 were reported to INAIL as an accident. In the same period INAIL noticed a decrease in reports of accidents and occupational disease overall, correlated to the effects of lockdown and smart working.