Associations of COVID-19 Symptoms with Omicron Subvariants BA.2 and BA.5, Host Status, and Clinical Outcomes: A Registry-Based Observational Study in Sapporo, Japan (preprint)

Background: Previous SARS-CoV-2 infection and vaccination, coupled to rapid evolution of SARS-CoV-2 variants, have modified COVID-19 clinical manifestations. We characterized clinical symptoms of COVID-19 individuals in omicron BA.2 and BA.5 Japanese pandemic periods to identify omicron and subvariant associations between symptoms, immune status, and clinical outcomes. Methods: Individuals registered in Sapporo's web-based COVID-19 information system entered 12 pre-selected symptoms, days since symptom onset, vaccination history, SARS-CoV-2 infection history, and background. Symptom frequencies, variables associated with symptoms, and symptoms associated with progression to severe disease were analysed. Results: For all omicron-infected individuals, cough was the most common symptom (62.7%), followed by sore throat (60.7%), nasal discharge (44.3%), and fever (38.8%). Omicron BA.5 infection was associated with a higher symptom burden than BA.2 in vaccinated and unvaccinated individuals. Omicron breakthrough-infected individuals with 3 or more vaccinations or previous infection were less likely to exhibit systemic symptoms, but more likely to exhibit upper respiratory symptoms. Infected elderly individuals had lower odds for all symptoms, but, when symptoms were manifest, systemic symptoms were associated with an increased risk, whereas upper respiratory symptoms with a decreased risk, of severe disease. Conclusion: Host immunological status, omicron subvariant, and age were associated with a spectrum of COVID-19 symptoms and outcomes. BA.5 produced a greater symptom burden than BA.2. Vaccination and prior infection mitigated systemic symptoms and improved outcomes, but increased upper respiratory tract symptom burden. Systemic, but not upper respiratory, symptoms in the elderly heralded severe disease.

C-Reactive Protein Level Predicts Need For Medical Intervention In Pregnant Women With SARS-CoV2 Infection: A Retrospective Study (preprint)

Background: During the Coronavirus disease 2019 (COVID-19) pandemic, many hospitals experienced a shortage of hospital beds. To make effective use of the limited available hospital space during the pandemic, we conducted this study to investigate the laboratory indices that identify pregnant women with SARS-CoV2 infection who require medical intervention. Methods: We carried out a retrospective analysis of pregnant women positive for COVID-19 who were admitted to Hokkaido University Hospital from September 2020 to June 2021. Medical interventions included oxygen supplementation, systemic corticosteroids, or supplemental liquids to treat infection-related symptoms. Results: Forty-two infected pregnant patients were admitted to the hospital, half of whom required medical intervention (n = 21). Fever, C-reactive protein , and platelet count are all associated with need for medical intervention. Of the 32 patients with a fever of ≥37.5℃ on days 0–3 after onset of syndromes, 22 (69%) continued to have a fever on days 4–6, of which 19 (86.4%) required medical intervention. C-reactive protein level and platelet count on days 4–6 predicted the presence or absence of medical intervention (area under the receiver operating characteristic curve = 0.913, and 0.856, respectively), with a sensitivity of 81% and specificity of 100% at a C-reactive protein cutoff of 1.28 mg/dL, with a sensitivity of 75% and specificity of 87% at a platelet count cutoff of 16.3 × 10⁴/μL. Conclusions: The need for medical intervention in pregnant patients can be predicted with high accuracy using a C-reactive protein cutoff of 1.28 mg/dL on days 4–6 after onset of syndromes. The presence of fever also may be an easy marker for selecting subjects who need or will need therapeutic intervention. These could be an effective triage method to determine appropriate indications for the hospitalization of pregnant women in future outbreaks.

Proposal of COVID-19 Clinical Risk Score for the management of suspected COVID-19 cases: a case control study (preprint)

BackgroundNo clinical scoring system has yet been established to estimate the likelihood of COVID-19 and to determine the suitability of diagnostic testing in suspected COVID-19 patients.MethodsThis was a single-center, retrospective, observational study of patients with suspected COVID-19 and confirmed COVID-19. Patient background, clinical course, laboratory and CT findings, and the presence of alternative diagnoses were evaluated. Clinical risk scores were developed based on clinical differences between patients with and those without COVID-19.ResultsAmong 110 patients suspected of COVID-19, 60.9% underwent PCR testing based on the judgment of physicians. Two patients were found to have COVID-19. The clinical characteristics of 108 non-COVID-19 patients were compared with those of 23 confirmed COVID-19 patients. Patients with COVID-19 were more likely to have a history of high-risk exposures and abnormal sense of taste and smell. Significantly higher rates of subnormal white blood cell count, lower eosinophil count, and lower procalcitonin level were observed in the COVID-19 group than in the non-COVID-19 group. When blood tests, CT findings, and the presence of alternative diagnoses were scored on an 11-point scale, i.e., “COVID-19 Clinical Risk Score”, the COVID-19 group scored significantly higher than the non-COVID-19 group, with more than four points in the COVID-19 group. All non-COVID cases that did not undergo PCR had a score of 4 or less.ConclusionsThe COVID-19 Clinical Risk Score enables risk classification of patients suspected of having COVID-19 and can help in decision-making in clinical practice, including appropriateness of diagnostic testing. 

Older age is associated with sustained detection of SARS-CoV-2 in nasopharyngeal swab samples (preprint)

PCR testing of nasopharyngeal swab samples is used for the diagnosis of coronavirus disease 2019 (COVID-19) and for determining timing of discharge. The viral load usually declines at convalescent phase, but sometimes remained positive for a long time even after relief of symptoms. In this study, we identified older age is associated with sustained detection of SARS-CoV-2 in nasopharyngeal swab samples.