Background:

the COVID-19 pandemic forced to extra occupational and individual measures in the industry.

Objectives:

to assess the incidence of SARS-CoV-2 and transmission chains, to control the spread of the disease and to assess the presence of anti- SARS-CoV-2 antibodies.

Methodology:

prospective longitudinal descriptive study (laboratory test) conducted after the appearance of a case of SARS-CoV-2 in a wood industry in the North of Portugal. A total of 873 workers participated in the study (mean age: 41.77 years, 50.4% men). Isolation and disinfection measures were implemented, as well as screening of the working population, and a combination of serological tests and RT-PCR.

Results:

the original case has an epidemiological link outside the industry. 31 workers (3.55%) had a positive result in serological tests, after, these employees were subjected to RT-PCR tests, which resulted in new cases. Subsequently, the 31 persons were re-tested with serological tests, 10 positive tests for IgM and 2 for IgG were founded.

Conclusion:

the serological test whose result was positive or negative, by itself, should not constitute evidence (exclusion) of infection. To limit the spread of the virus, it is crucial to ensure that the diagnosis is made with RT-PCR tests. The promising association between IgG and immunity needs further evidence. With the measures implemented, it was possible to control the spread of the disease and give permission to return working.