Seroprevalence Survey of Anti-SARS-CoV-2 Antibodies in a Population of Emilia-Romagna Region, Northern Italy.

Italy was the first Western European country to be severely hit by the COVID-19 pandemic. Variations in seroprevalence rates were reported according to geographical and temporal differences of previous surveys, as well as depending on demographic and occupational factors. In this cross-sectional study, we evaluated the prevalence of anti-SARS-CoV-2 antibodies in a population of the Emilia-Romagna region in Northern Italy after the first wave in the period from 26 September 2020−26 March 2021. We included 5128 subjects who voluntarily underwent serological tests to determine anti-SARS-CoV-2 antibody positivity, including both self-referred individuals (24.2%) and workers adhering to company screening programs (76.8%). Overall, seroprevalence was 11.3%, higher in self-referred (13.8%) than employed-referred (10.5%) individuals. A slightly higher seroprevalence emerged in women compared to men (12.3% and 10.7%), as well as in the extreme age categories (18.6% for 60−69 years, 18.0% for ≥70 years, and 17.1% for <20 years compared to 7.6% for 20−39 years). Healthcare professionals showed the highest prevalence of seropositivity (22.9%), followed by workers in direct contact with customers, such as the communication, finance, and tourism sectors (15.7%). Overall subgroups seroprevalence increased compared to the first wave data but the trends agreed between the first and subsequent waves, except for an increase in the younger age group and in the sector in direct contact with customers. Among the occupational categories, our study confirms that healthcare workers and workers in the sports sector were at high risk of exposure to SARS-CoV-2.

Seroprevalence of anti-SARS-CoV-2 antibodies in the Northern Italy population before the COVID-19 second wave.

OBJECTIVES: The COVID-19 pandemic is due to SARS-CoV-2 coronavirus infections. It swept across the world in the spring of 2020, and so far it has caused a huge number of hospitalizations and deaths. In the present study, the authors investigated serum anti-SARS-CoV-2 antibody prevalence in the period of June 1-September 25, 2020, in 7561 subjects in Modena, Northern Italy. MATERIAL AND METHODS: The study population included 5454 workers referred to testing by their companies, and 2107 residents in the Modena area who accessed testing through self-referral. RESULTS: The authors found the overall seroprevalence to be 4.7% (95% confidence interval [CI] 4.2-5.2%), which was higher in women (5.4%, 95% CI: 4.5-6.2%) than in men (4.3%, 95% CI: 3.7-4.9%), and in the oldest age groups (7.3%, 95% CI: 5.2-9.3% for persons aged 60-69 years, and 11.8%, 95% CI: 8.6-15.1%, for persons aged ≥70 years). Among the occupational categories, the highest seroprevalence was found in healthcare workers (8.8%, 95% CI: 7.0-10.5%), dealers and vehicle repairers (5.2%, 95% CI: 2.9-7.6%), and workers in the sports sector (4.0%, 95% CI: 1.8-6.1%), while there was little or no such evidence for those employed in sectors such as transport and storage, accommodation and restaurant services, and the school system. CONCLUSIONS: These results have allowed, for the first time, to assess population seroprevalence in this area of Italy severely hit by the epidemic, while at the same time identifying the subgroups at a higher risk of exposure to SARS-CoV-2. Int J Occup Med Environ Health. 2022;35(1):63-74.