Abstract
Background & objectives: COVID-19 cases have been rising rapidly in countries where the SARS-CoV-2 variant of concern (VOC), Omicron (B.1.1.529) has been reported. We conducted a study to describe the epidemiological and clinical characteristics and outcomes of COVID-19 patients with ‘S’ gene target failure (SGTF, suspected Omicron). Furthermore, their clinical outcomes with COVID-19 patients with non-SGTF (non-Omicron) were also compared.
Methods: This study was conducted in Tamil Nadu, India, between December 14, 2021 and January 7, 2022 among patients who underwent reverse transcription-PCR testing for SARS-CoV-2 in four laboratories with facilities for S gene screening. Consecutively selected COVID-19 patients with SGTF were telephonically contacted, seven and 14 days respectively after their date of positive result to collect information on the socio-demographic characteristics, previous history of COVID-19, vaccination status and clinical course of illness along with treatment details. To compare their outcomes with non-SGTF patients, one randomly suspected non-Omicron case for every two suspected Omicron cases from the line-list were selected, matching for the date of sample collection and the testing laboratory.
Results: A total of 1175 SGTF COVID-19 patients were enrolled for this study. Almost 6 per cent (n=72) reported a history of previous infection. 141 (13.5%) suspected Omicron cases were non-vaccinated, while 148 (14.2%) and 703 (67.4%) had received valid one and two doses of COVID-19 vaccines, respectively. Predominant symptoms reported included fever (n=508, 43.2%), body pain (n=275, 23.4%), running nose (n=261, 22.2%) and cough (n=249, 21.2%). Five (0.4%) of the 1175 suspected Omicron cases required oxygen supplementation as compared to ten (1.6%) of the 634 suspected non-Omicron cases. No deaths were reported among omicron suspects, whereas there were four deaths among suspected non-Omicron cases.
Interpretation & conclusions: Majority of the suspected Omicron cases had a mild course of illness. The overall severity of these cases was less compared to the suspected non-Omicron cases.
Keywords: B.1.1.529; COVID-19; Omicron; SARS-CoV-2; epidemiology; severity; variant of concern.
【저자키워드】 COVID-19, SARS-CoV-2, Epidemiology, severity, omicron, B.1.1.529, Variant of concern., 【초록키워드】 Treatment, vaccination, Clinical characteristics, VoC, India, variant, Infection, Symptom, outcome, cough, reverse transcription-PCR, Laboratory, Clinical outcome, COVID-19 vaccines, Clinical course, Characteristics, Fever, Patient, Pain, death, Mild, epidemiological, information, patients, S gene, dose, COVID-19 patient, COVID-19 case, positive result, oxygen supplementation, country, socio-demographic, Randomly, gene target, Seven, Course, enrolled, selected, reported, required, conducted, less, rising, the SARS-CoV-2, with COVID-19, 【제목키워드】 India, variant, clinical, Patient,