Analysis of SARS-CoV-2 genomic surveillance data during the Delta and Omicron waves at a Saudi tertiary referral hospital.

BACKGROUND: Studying the genomic evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may help determine outbreak clusters and virus transmission advantages to aid public health efforts during the pandemic. Thus, we tracked the evolution of SARS-CoV-2 by variant epidemiology, breakthrough infection, and patient characteristics as the virus spread during the Delta and Omicron waves. We also conducted phylogenetic analyses to assess modes of transmission. METHODS: Nasopharyngeal samples were collected from a cohort of 900 patients with positive polymerase chain reaction (PCR) test results confirming COVID-19 disease. Samples underwent real-time PCR detection using TaqPath assays. Sequencing was performed with Ion GeneStudio using the Ion AmpliSeq™ SARS-CoV-2 panel. Variant calling was performed with Torrent Suite™ on the Torrent Server. For phylogenetic analyses, the MAFFT tool was used for alignment and the maximum likelihood method with the IQ-TREE tool to build the phylogenetic tree. Data were analyzed using SAS statistical software. Analysis of variance or t tests were used to assess continuous variables, and χ2 tests were used to assess categorical variables. Univariate and multivariate logistic regression analyses were preformed to estimate odds ratios (ORs). RESULTS: The predominant variants in our cohort of 900 patients were non-variants of concern (11.1 %), followed by Alpha (4.1 %), Beta (5.6 %), Delta (21.2 %), and Omicron (58 %). The Delta wave had more male than female cases (112 vs. 78), whereas the Omicron wave had more female than male cases (311 vs. 208). The oldest patients (mean age, 43.4 years) were infected with non-variants of concern; the youngest (mean age, 33.7 years), with Omicron. Younger patients were mostly unvaccinated, whereas elderly patients were mostly vaccinated, a statistically significant difference. The highest risk for breakthrough infection by age was for patients aged 30-39 years (OR = 12.4, CI 95 %: 6.6-23.2), followed by patients aged 40-49 years (OR = 11.2, CI 95 %: 6.1-23.1) and then 20-29 years (OR = 8.2, CI 95 %: 4.4-15.4). Phylogenetic analyses suggested the interaction of multiple cases related to outbreaks for breakthrough infections, healthcare workers, and intensive care unit admission. CONCLUSION: The findings of this study highlighted several major public health ramifications, including the distribution of variants over a wide range of demographic and clinical variables and by vaccination status.

Duration of viral shedding in patients with COVID-19 and the redetectable positive cases with SARS-CoV-2: A hospital experience.

Background: The study aimed to estimate the duration of viral shedding (DVS) in patients with confirmed coronavirus disease 2019 (COVID-19), investigated the factors affecting that duration, and identified the redetectable positive (RP) cases in the recovered COVID-19 patients in Prince Sultan Military Medical City (PSMMC). Methods: The study was a retrospective record base design in the PSMMC that included 171 confirmed COVID-19 patients from 15 March to 31 May 2020. Their clinical characteristics and laboratory findings were retrieved and reviewed based on the PSMMC COVID-19 database and the Ministry of Health (MOH) Health Electronic Surveillance Network. Data analysis used the SPSS software package to measure the DVS, explore its potential factors, and identify the RP cases. The data presented as frequency distribution tables, medians, and interquartile range (IQR). Mann-Whitney U and Kruskal-Wallis tests compared the medians to explore the significant variables that affect DVS. Results: The median DVS was 11 days, IQR was 7 to 15 days, and statistically significant longer the patient presented with fever (P = 0.025), among health care workers (HCWs) (P = 0.020), and the age group above 65 (P = 0.039). Overall, 13 patients (7.6%) were RP, statistically significantly higher among the contacts to confirmed COVID-19 cases. Conclusions: The DVS in PSMMC COVID-19 patients is comparable to the isolation period approved by MOH. Fever was a risk factor for a prolonged DVS, advised an extended follow-up period for these patients. RP cases were significantly higher among the contacts to COVID-19 cases than non-contacts. The study suggests future comprehensive research on the RP characteristics.