Cluster of COVID-19 in northern France: A retrospective closed cohort study
Open Access
- 23 April 2020
- preprint content
- other
- Published by Cold Spring Harbor Laboratory
Abstract
Background: The Oise department in France has been heavily affected by COVID-19 in early 2020. Methods: Between 30 March and 4 April 2020, we conducted a retrospective closed cohort study among pupils, their parents and siblings, as well as teachers and non-teaching staff of a high-school located in Oise. Participants completed a questionnaire that covered history of fever and/or respiratory symptoms since 13 January 2020 and had blood tested for the presence of anti-SARS-CoV-2 antibodies. The infection attack rate (IAR) was defined as the proportion of participants with confirmed SARS-CoV-2 infection based on antibody detection. Blood samples from two blood donor centres collected between 23 and 27 March 2020 in the Oise department were also tested for presence of anti-SARS-CoV-2 antibodies. Findings: Of the 661 participants (median age: 37 years), 171 participants had anti-SARS-CoV-2 antibodies. The overall IAR was 25.9% (95% confidence interval (CI) = 22.6-29.4), and the infection fatality rate was 0% (one-sided 97.5% CI = 0-2.1). Nine of the ten participants hospitalised since mid-January were in the infected group, giving a hospitalisation rate of 5.3% (95% CI = 2.4-9.8). Anosmia and ageusia had high positive predictive values for SARS-CoV-2 infection (84.7% and 88.1%, respectively). Smokers had a lower IAR compared to non-smokers (7.2% versus 28.0%, P <0.001). The proportion of infected individuals who had no symptoms during the study period was 17.0% (95% CI = 11.2-23.4). The proportion of donors with anti-SARS-CoV-2 antibodies in two nearby blood banks of the Oise department was 3.0% (95% CI = 1.1-6.4). Interpretation: The relatively low IAR observed in an area where SARS-CoV-2 actively circulated weeks before confinement measures indicates that establishing herd immunity will take time, and that lifting these measures in France will be long and complex.Keywords
This publication has 18 references indexed in Scilit:
- Severe Acute Respiratory Syndrome Coronavirus 2-Specific Antibody Responses in Coronavirus Disease PatientsEmerging Infectious Diseases, 2020
- Spread of SARS-CoV-2 in the Icelandic PopulationNew England Journal of Medicine, 2020
- Coronavirus Disease-19: The First 7,755 Cases in the Republic of KoreaOsong Public Health and Research Perspectives, 2020
- SARS-CoV-2 serological analysis of COVID-19 hospitalized patients, pauci-symptomatic individuals and blood donorsPublished by Cold Spring Harbor Laboratory ,2020
- Coronavirus Disease 2019 in Children — United States, February 12–April 2, 2020Mmwr. Morbidity and Mortality Weekly Report, 2020
- Virological assessment of hospitalized patients with COVID-2019Nature, 2020
- Estimates of the severity of coronavirus disease 2019: a model-based analysisThe Lancet Infectious Diseases, 2020
- Epidemiology and Transmission of COVID-19 in Shenzhen China: Analysis of 391 cases and 1,286 of their close contactsPublished by Cold Spring Harbor Laboratory ,2020
- Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019Published by Cold Spring Harbor Laboratory ,2020
- First cases of coronavirus disease 2019 (COVID-19) in France: surveillance, investigations and control measures, January 2020Eurosurveillance, 2020