Abstract
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Abstract; Background: The incubation period for COVID-19, which is the time from exposure to symptom onset, is on average five to six days but reach 14 days. The question is, the timing of onset of various signs and symptoms of COVID-19 along the period amongst cases in Uganda is not known. Methodology: We utilized administrative data of publicly reported real-time RT-PCR laboratory COVID-19 confirmed cases in Uganda to investigate the timing of symptom onset, from 21-Marto 4-Sep-2020. Since timing of COVID-19 symptom onset is highly likely to be an interval rather than a point estimate, we generated three tertile categories of the period – 1st, 2nd, and 3rd tertiles denoting symptom presentation within 3, 4-6 and at least 7-days respectively. All signs and symptoms reported in the database were considered. We did not make any inferences about asymptomatic infection with SARS-COV-2. We analysed using frequency distributions, Chi-square test and Multinomial Logistic Regression; and controlled for age and sex.Results: We analysed a total of 420 symptomatic case-patients. The case-patients were predominantly male, 72.0% (304/420), median age of 33 years, IQR=26-41. The common symptoms of SARS-CoV-2 were: cough (47.6%), running nose (46.2%), fever (27.4%), headache (26.4%) and sore throat (20.5%). We utilized only 293 COVID-19 symptomatic cases that had clinical symptom onset date recorded for analysis of the timing of symptom onset. Most case-patients, 37.5% (109/293) - presented symptom within 3-days after laboratory confirmation, 31.4% (92/293) had symptoms in the 2nd and another 31.4% (92/293) in 3rd tertile, denoting 4-6 days and at-least 7 days after exposure, respectively. Running nose (RRR =0.45, 95% CI 0.24 - 0.84) and chest pain (RRR = 0.64, 95% CI 0.09 – 0.72) were less likely to occur in the 1st tertile and 2nd tertile rather than in the 3rd tertile. Case-patients aged ≥20yrs were less likely to have symptoms in the 1st and 2nd tertile compared to ≤20 years (p < 0.05). Conclusion: Our study provides empirical evidence for epidemiological characterization of cases by signs and symptoms along the incubation period among case-patients. This complements the current proposals for the length of active monitoring of persons exposed to SARS-CoV-2.