Serological investigation of asymptomatic cases of SARS-CoV-2 infection reveals weak and declining antibody responses.

Without an effective vaccine against SARS-CoV-2, the build-up of herd immunity through natural infection has been suggested as a means to control COVID-19. Although population immunity is typically estimated by the serological investigation of recovered patients, humoral immunity in asymptomatic subjects has not been well studied, although they represent a large proportion of all SARS-CoV-2 infection cases. In this study, we conducted a serosurvey of asymptomatic infections among food workers and performed serological and cellular response analyses of asymptomatic subjects in Wuhan, the original epicenter of the COVID-19 outbreak. Our data showed that up to 5.91% of the food workers carried SARS-CoV-2 IgG antibodies asymptomatically; however, in 90.4% of them, the antibody level declined over a 2-week period. IgM and IgG antibodies, including neutralizing antibodies, were significantly lower in asymptomatic subjects than in recovered symptomatic patients with similar disease courses. Furthermore, the asymptomatic subjects showed lymphopenia and a prominent decrease in the B-cell population, as well as a low frequency of antibody-secreting cells and a low cytokine response. These factors probably contributed to the low and unsustained antibody levels in asymptomatic subjects. Our results show that asymptomatic subjects are likely to be vulnerable to SARS-CoV-2 reinfection, and neither the proportion of population immunity nor the breadth of immune responses is sufficient for herd immunity.

Prolonged shedding of severe acute respiratory syndrome coronavirus 2 in patients with COVID-19.

Following acute infection, individuals COVID-19 may still shed SARS-CoV-2 RNA. However, limited information is available regarding the active shedding period or whether infectious virus is also shed. Here, we monitored the clinical characteristics and virological features of 38 patients with COVID-19 (long-term carriers) who recovered from the acute disease, but still shed viral RNA for over 3 months. The median carrying history of the long-term carriers was 92 days after the first admission, and the longest carrying history was 118 days. Negative-positive viral RNA-shedding fluctuations were observed. Long-term carriers were mostly elderly people with a history of mild infection. Infectious SARS-CoV-2 was isolated from the sputum, where high level viral RNA was found. All nine full-length genomes of samples obtained in March-April 2020 matched early viral clades circulating in January-February 2020, suggesting that these patients persistently carried SARS-CoV-2 and were not re-infected. IgM and IgG antibodies and neutralizing-antibody profiles were similar between long-term carriers and recovered patients with similar disease courses. In summary, although patients with COVID-19 generated neutralizing antibodies, they may still shed infectious SARS-CoV-2 for over 3 months. These data imply that patients should be monitored after discharge to control future outbreaks.

Comparison of Hospitalized Patients With ARDS Caused by COVID-19 and H1N1.

BACKGROUND: Since the outbreak of coronavirus disease 2019 (COVID-19) in China in December 2019, considerable attention has been focused on its elucidation. However, it is also important for clinicians and epidemiologists to differentiate COVID-19 from other respiratory infectious diseases such as influenza viruses. RESEARCH QUESTION: The aim of this study was to explore the different clinical presentations between COVID-19 and influenza A (H1N1) pneumonia in patients with ARDS. STUDY DESIGN AND METHODS: This analysis was a retrospective case-control study. Two independent cohorts of patients with ARDS infected with either COVID-19 (n = 73) or H1N1 (n = 75) were compared. Their clinical manifestations, imaging characteristics, treatments, and prognosis were analyzed and compared. RESULTS: The median age of patients with COVID-19 was higher than that of patients with H1N1, and there was a higher proportion of male subjects among the H1N1 cohort (P < .05). Patients with COVID-19 exhibited higher proportions of nonproductive coughs, fatigue, and GI symptoms than those of patients with H1N1 (P < .05). Patients with H1N1 had higher Sequential Organ Failure Assessment (SOFA) scores than patients with COVID-19 (P < .05). The Pao2/Fio2 of 198.5 mm Hg in the COVID-19 cohort was significantly higher than the Pao2/Fio2 of 107.0 mm Hg in the H1N1 cohort (P < .001). Ground-glass opacities was more common in patients with COVID-19 than in patients with H1N1 (P < .001). There was a greater variety of antiviral therapies administered to COVID-19 patients than to H1N1 patients. The in-hospital mortality of patients with COVID-19 was 28.8%, whereas that of patients with H1N1 was 34.7% (P = .483). SOFA score-adjusted mortality of H1N1 patients was significantly higher than that of COVID-19 patients, with a rate ratio of 2.009 (95% CI, 1.563-2.583; P < .001). INTERPRETATION: There were many differences in clinical presentations between patients with ARDS infected with either COVID-19 or H1N1. Compared with H1N1 patients, patients with COVID-19-induced ARDS had lower severity of illness scores at presentation and lower SOFA score-adjusted mortality.

Predictors of mortality for patients with COVID-19 pneumonia caused by SARS-CoV-2: a prospective cohort study.

The aim of this study was to identify factors associated with the death of patients with COVID-19 pneumonia caused by the novel coronavirus SARS-CoV-2.All clinical and laboratory parameters were collected prospectively from a cohort of patients with COVID-19 pneumonia who were hospitalised to Wuhan Pulmonary Hospital (Wuhan City, Hubei Province, China) between 25 December 2019 and 7 February 2020. Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.146­17.394; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 0.755­8.044; p=0.007), CD3+CD8+ T-cells ≤75 cells·µL−1 (OR 3.982, 95% CI 1.132­14.006; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.166­14.253; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia." has been corrected to: "Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.201−11.803; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 1.279−4.747; p=0.007), CD3+CD8+ T-cells ≤75 cells·µL−1 (OR 3.982, 95% CI 1.761­9.004; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.778­9.349; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia. In a sex-, age- and comorbid illness-matched case-control study, CD3+CD8+ T-cells ≤75 cells·µL-1 and cardiac troponin I ≥0.05 ng·mL-1 remained as predictors for high mortality from COVID-19 pneumonia.We identified four risk factors: age ≥65 years, pre-existing concurrent cardiovascular or cerebrovascular diseases, CD3+CD8+ T-cells ≤75 cells·µL-1 and cardiac troponin I ≥0.05 ng·mL-1 The latter two factors, especially, were predictors for mortality of COVID-19 pneumonia patients.

Hospitalization and Critical Care of 109 Decedents with COVID-19 Pneumonia in Wuhan, China.

Rationale: The current outbreak of coronavirus disease (COVID-19) pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Wuhan, China, spreads across national and international borders. The overall death rate of COVID-19 pneumonia in the Chinese population was 4%.Objectives: To describe the process of hospitalization and critical care of patients who died of COVID-19 pneumonia.Methods: This was a multicenter observational study of 109 decedents with COVID-19 pneumonia from three hospitals in Wuhan. Demographic, clinical, laboratory, and treatment data were collected and analyzed, and the final date of follow-up was February 24, 2020.Results: The mean age of 109 decedents with COVID-19 pneumonia was 70.7 years, 35 patients (32.1%) were female, and 85 patients (78.0%) suffered from one or more underlying comorbidities. Multiple organ failure, especially respiratory failure and heart failure, appeared in all patients even at the early stage of disease. Overall, the mean time from onset of symptoms to death was 22.3 days. All 109 hospitalized patients needed admission to an intensive care unit (ICU); however, because of limited availability, only 51 (46.8%) could be admitted. The period from hospitalization to death in the ICU group and non-ICU group was 15.9 days (standard deviation = 8.8 d) and 12.5 days (8.6 d, P = 0.044), respectively.Conclusions: Mortality due to COVID-19 pneumonia was concentrated in patients above the age of 65 years, especially those with major comorbidities. Patients who were admitted to the ICU lived longer than those who were not. Our findings should aid in the recognition and clinical management of such infections, especially with regard to ICU resource allocation.

Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes.

In December 2019, a novel coronavirus (2019-nCoV) caused an outbreak in Wuhan, China, and soon spread to other parts of the world. It was believed that 2019-nCoV was transmitted through respiratory tract and then induced pneumonia, thus molecular diagnosis based on oral swabs was used for confirmation of this disease. Likewise, patient will be released upon two times of negative detection from oral swabs. However, many coronaviruses can also be transmitted through oral-fecal route by infecting intestines. Whether 2019-nCoV infected patients also carry virus in other organs like intestine need to be tested. We conducted investigation on patients in a local hospital who were infected with this virus. We found the presence of 2019-nCoV in anal swabs and blood as well, and more anal swab positives than oral swab positives in a later stage of infection, suggesting shedding and thereby transmitted through oral-fecal route. We also showed serology test can improve detection positive rate thus should be used in future epidemiology. Our report provides a cautionary warning that 2019-nCoV may be shed through multiple routes.