A COVID-19 outbreak in a rheumatology department upon the early days of the pandemic

Abstract

Objectives: To describe our experience with a coronavirus disease 2019 (COVID-19) outbreak within a large rheumatology department, early in the pandemic. Methods: Symptomatic and asymptomatic healthcare workers (HCWs) had a naso-oropharyngeal swab for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and were followed clinically. Reverse transcription polymerase-chain reaction (RT-PCR) was repeated to document cure, and serological response was assessed. Patients with risk contacts within the department in the 14 days preceding the outbreak were screened for COVID-19 symptoms. Results: 14/34 HCWs (41%; 40±14 years, 71% female) tested positive for SARS-CoV-2, and 11/34 (32%) developed symptoms but were RT-PCR-negative. Half of RT-PCR-positive HCWs did not report fever, cough, or dyspnoea before testing, which were absent in 3/14 cases (21%). Mild disease prevailed (79%), but 3 HCWs had moderate disease requiring further assessment, which excluded severe complications. Nevertheless, symptom duration (28±18 days), viral shedding (31±10 days post-symptom onset, range 15-51) and work absence (29±28 days) were prolonged. 13/14 (93%) of RT-PCR-positive and none of the RT-PCR-negative HCWs had a positive humoral response, with higher IgG-index in individuals over 50 years (14.5±7.7 vs 5.0±4.4, p=0.012). Of 617 rheumatic patients, 8 (1.3%) developed COVID-19 symptoms (1/8 hospitalisation, 8/8 complete recovery), following a consultation/procedure with an asymptomatic (7/8) or mildly-symptomatic (1/8) HCW. Conclusions: A COVID-19 outbreak can occur among HCWs and rheumatic patients, swiftly spreading over the presymptomatic stage. Mild disease without typical symptoms should be recognised, and may evolve with delayed viral shedding, prolonged recovery, and adequate immune response in most individuals.

Proportion of asymptomatic infection among COVID-19 positive persons and their transmission potential: A systematic review and meta-analysis

“…Overall, 22 unique cohorts of participants described in 24 studies (15 cohorts, 7 cross sectional) reported the proportion of asymptomatic infection at initial testing and/or the proportion of COVID-19 infections remaining asymptomatic throughout follow-up; study characteristics are summarized in Table 1 . Study cohorts were from the USA (n = 10) [ 6 , 9 , 60 – 62 , 66 , 69 , 73 , 75 , 78 , 80 , 81 ], Europe (n = 8) [ 63 , 67 , 68 , 70 , 72 , 74 , 76 , 77 ], and Asia (n = 4) [ 65 , 70 , 79 , 84 ]. Definition of asymptomatic infection was variable among studies, ranging from absence of symptoms in the previous 14 days to only absence of symptoms at time of testing.…”

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: update of a living systematic review and meta-analysis

“…Owing to the change in eligible study designs, this update excludes 66 articles from earlier versions, comprising 23 contact tracing studies or outbreak investigations, 39 screening studies, and four mathematical models (S1 Table). This review version included a total of 107 studies addressing one or more objectives; 94 empirical studies that estimate the proportion of people with asymptomatic SARS-CoV-2 (summarised in Table 1 and S2 Table) [39-48, 50-54, 56-80, 82-90, 92-97, 99-102, 104-138], five studies reporting on secondary attack rates [119, 129, 138–140], and 11 mathematical modelling studies reporting on the contribution of asymptomatic or presymptomatic infection to all SARS-CoV-2 transmission [7, 49, 55, 81, 91, 98, 103, 141–144].…”

“…The 94 studies reported on 16,193 people with SARS-CoV-2 infection (5,905 defined as having asymptomatic infection) in 31 countries [39-48, 50-54, 56-80, 82-90, 92-97, 99-102, 104-138] (Table 1). Thirty-two studies, including 9,121 infected people, were done in the United States (S3 Table).…”

“…Thirty-two studies, including 9,121 infected people, were done in the United States (S3 Table). At time of the latest search date, 17 records were preprints, 14 of which had been published in peer-reviewed journals by 23 November 2021 [7, 49, 55, 89, 92, 98, 102, 105, 125, 126, 128, 133, 141, 145] and 3 were still preprints [95, 96, 144]. In all included studies, 86 followed participants for seven days or more, 19 followed participants for at least 14 days after a known exposure, 27 followed participants until they had at least one negative RT-PCR test and 29 studies used more than one method of follow-up (Table 1, S2 Table).…”

“…The IQR of estimates for all 94 included studies was 13-45% and the prediction interval from random-effects meta-analysis was 2-89% (S2 Fig). In studies enrolling people found through contact or outbreak investigations, for example in long-term care facilities, in aeroplanes, or on cruise ships, we estimated a summary estimate for the proportion asymptomatic (18%, 95% CI 14-24%, prediction interval 3-64%, IQR 8-35%, 40 studies [53, 60, 62, 65–68, 71, 73, 74, 82–86, 88, 90, 92, 93, 101, 105, 111, 112, 114–117, 119–123, 128–130, 132, 133, 136–138]. The estimated proportions of asymptomatic SARS-CoV-2 infections were similar in studies of contact investigations (16%, 95% CI 10-25%) and outbreak investigations (19%, 95% CI 14-26%) (S3 Fig).…”