Risk factors for SARS-CoV-2 transmission in close contacts of adults at high risk of infection due to occupation: results from the contact tracing strategy of the CoVIDA epidemiological surveillance study in Bogotá, Colombia, in 2020-2021

• Published in: BMJ open Vol. 12; no. 12; p. e062487
• Main Authors: Ramírez Varela, Andrea, Contreras-Arrieta, Sandra, Tamayo-Cabeza, Guillermo, Salas Zapata, Leonardo, Caballero-Díaz, Yuldor, Hernández Florez, Luis Jorge, Benavidez, Andrés Patiño, Laajaj, Rachid, De la Hoz, Fernando, Buitrago Gutierrez, Giancarlo, Restrepo, Silvia, Behrentz, Eduardo
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 23.12.2022; BMJ Publishing Group
• Series: Original research
• Subjects: Adult; Asymptomatic; Colombia - epidemiology; Contact tracing; Contact Tracing - methods; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 diagnostic tests; COVID-19 Testing; COVID-19 vaccines; Disease transmission; Epidemiology; Health surveillance; Humans; Immunization; Infections; Medical personnel; Mortality; Occupations; Pandemics; Public health; Risk Factors; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Sociodemographics; Variables; Colombia; COVID-19; PUBLIC HEALTH; EPIDEMIOLOGY
• ISSN: 2044-6055; 2044-6055
• DOI: 10.1136/bmjopen-2022-062487

To estimate the risk factors for SARS-CoV-2 transmission in close contacts of adults at high risk of infection due to occupation, participants of the CoVIDA study, in Bogotá D.C., Colombia. The CoVIDA study was the largest COVID-19 intensified sentinel epidemiological surveillance study in Colombia thus far, performing over 60 000 RT-PCR tests for SARS-CoV-2 infection. The study implemented a contact tracing strategy (via telephone call) to support traditional surveillance actions performed by the local health authority. Close contacts of participants from the CoVIDA study. SARS-CoV-2 testing results were obtained (RT-PCR with CoVIDA or self-reported results). The secondary attack rate (SAR) was calculated using contacts and primary cases features. The CoVIDA study performed 1257 contact tracing procedures on primary cases. A total of 5551 close contacts were identified and 1050 secondary cases (21.1%) were found. The highest SAR was found in close contacts: (1) who were spouses (SAR=32.7%; 95% CI 29.1% to 36.4%), (2) of informally employed or unemployed primary cases (SAR=29.1%; 95% CI 25.5% to 32.8%), (3) of symptomatic primary cases (SAR of 25.9%; 95% CI 24.0% to 27.9%) and (4) living in households with more than three people (SAR=22.2%; 95% CI 20.7% to 23.8%). The spouses (OR 3.85; 95% CI 2.60 to 5.70), relatives (OR 1.89; 95% CI 1.33 to 2.70) and close contacts of a symptomatic primary case (OR 1.48; 95% CI 1.24 to 1.77) had an increased risk of being secondary cases compared with non-relatives and close contacts of an asymptomatic index case, respectively. Contact tracing strategies must focus on households with socioeconomic vulnerabilities to guarantee isolation and testing to stop the spread of the disease.