Few SARS-CoV-2 infections detected in Newfoundland and Labrador in the absence of Public Health Laboratory-based confirmation

• Published in: PloS one Vol. 17; no. 1; p. e0262957
• Main Authors: Ings, Danielle P., Hatfield, Keeley M., Fifield, Kathleen E., Harnum, Debbie O. A., Holder, Kayla A., Russell, Rodney S., Grant, Michael D.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.01.2022; Public Library of Science (PLoS)
• Subjects: Adult; Antibodies; Antigens; Biology and life sciences; Coronaviruses; COVID-19; COVID-19 - diagnosis; COVID-19 - epidemiology; COVID-19 - immunology; COVID-19 - psychology; COVID-19 Testing; Female; Health risks; Humans; Incidence; Infections; Male; Medicine; Medicine and health sciences; Newfoundland and Labrador - epidemiology; Pandemics; Perception; Plasma; Proteins; Public awareness; Public health; Research and Analysis Methods; Risk analysis; Risk factors; Risk perception; Serology; Severe acute respiratory syndrome coronavirus 2; Vaccination; Vaccines; Viral diseases; Volunteers; Newfoundland and Labrador; Newfoundland & Labrador Canada; Canada; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0262957

To assess the incidence of COVID-19 infection in the absence of a confirmatory test in persons suspecting they contracted COVID-19 and elucidate reasons for their belief. We recruited persons with a confirmed COVID-19 diagnosis and persons who believed they may have contracted COVID-19 between December, 2019 and April, 2021 into a study of immunity against SARS-CoV-2. An intake questionnaire captured their perceived risk factors for exposure and symptoms experienced, including symptom duration and severity. ELISA testing against multiple SARS-CoV-2 antigens was done to detect antibodies against SARS-CoV-2. No participant had received COVID-19 vaccination prior to the time of testing. The vast majority of study subjects without Public Health confirmation of infection had no detectable antibodies against SARS-CoV-2. Suspected infection with SARS-CoV-2 generally involved experiencing symptoms common to many other respiratory infections. Unusually severe or persistent symptoms often supported suspicion of infection with SARS-CoV-2 as did travel or contact with travelers from outside Newfoundland and Labrador. Rare cases in which antibodies against SARS-CoV-2 were detected despite negative results of Public Health testing for SARS-CoV-2 RNA involved persons in close contact with confirmed cases. Broad public awareness and declaration of pandemic status in March, 2020 contributed to the perceived risk of contracting COVID-19 in Newfoundland and Labrador from late 2019 to April 2021 and raised expectation of its severity. Serological testing is useful to diagnose past infection with SARS-CoV-2 to accurately estimate population exposure rates.