Infection with wild-type SARS-CoV-2 elicits broadly neutralizing and protective antibodies against omicron subvariants.

The omicron variants of SARS-CoV-2 have substantial ability to escape infection- and vaccine-elicited antibody immunity. Here, we investigated the extent of such escape in nine convalescent patients infected with the wild-type SARS-CoV-2 during the first wave of the pandemic. Among the total of 476 monoclonal antibodies (mAbs) isolated from peripheral memory B cells, we identified seven mAbs with broad neutralizing activity to all variants tested, including various omicron subvariants. Biochemical and structural analysis indicated the majority of these mAbs bound to the receptor-binding domain, mimicked the receptor ACE2 and were able to accommodate or inadvertently improve recognition of omicron substitutions. Passive delivery of representative antibodies protected K18-hACE2 mice from infection with omicron and beta SARS-CoV-2. A deeper understanding of how the memory B cells that produce these antibodies could be selectively boosted or recalled can augment antibody immunity against SARS-CoV-2 variants.

Omicron variants escape the persistent SARS-CoV-2-specific antibody response in 2-year COVID-19 convalescents regardless of vaccination.

With the ongoing COVID-19 pandemic and the emergence of various SARS-CoV-2 variants, a comprehensive evaluation of long-term efficacy of antibody response in convalescent individuals is urgently needed. Several longitudinal studies had reported the antibody dynamics after SARS-CoV-2 acute infection, but the follow-up was mostly limited to 1 year or 18 months at the maximum. In this study, we investigated the durability, potency, and susceptibility to immune evasion of SARS-CoV-2-specific antibody in COVID-19 convalescents for 2 years after discharge. These results showed the persistent antibody-dependent immunity could protect against the WT and Delta variant to some extent. However, the Omicron variants (BA.1, BA.2, and BA.4/5) largely escaped this preexisting immunity in recovered individuals. Furthermore, we revealed that inactivated vaccines (BBIBP-CorV, CoronaVac, or KCONVAC) could improve the plasma neutralization and help to maintain the broadly neutralizing antibodies at a certain level. Notably, with the time-dependent decline of antibody, 1-dose or 2-dose vaccination strategy seemed not to be enough to provide immune protection against the emerging variants. Overall, these results facilitated our understanding of SARS-CoV-2-induced antibody memory, contributing to the development of immunization strategy against SARS-CoV-2 variants for such a large number of COVID-19 survivors.

Long-term sequelae of different COVID-19 variants: The original strain versus the Omicron variant.

Although Omicron appears to cause less severe acute illness than the original strain, the potential for large numbers of patients to experience long COVID is a major concern. Little is known about the recovery phase in cases of Omicron, highlighting the importance of dynamically monitor long COVID in those patients. Subjects of the current study were patients available for a three-month follow-up who were admitted from January 13 to May 22, 2020 (period of the original strain) and from January 1 to May 30, 2022 (period of Omicron). Twenty-eight-point-four percent of patients infected with the original strain had long-term symptoms of COVID-19 and 5.63% of those infected with the Omicron strain had such symptoms. The most common symptom was a cough (18.5%), followed by tightness in the chest (6.5%), in patients infected with the original strain. Fatigue (2.4%) and dyspnea (1.7%) were the most commonly reported symptoms in patients infected with the Omicron strain. The respiratory system is the primary target of SARSCoV-2. Supportive treatment is the basis for the treatment of respiratory symptoms in patients with COVID-19. Quality sleep and good nutrition may alleviate fatigue and mental issues. Further knowledge about a long-term syndrome due to Omicron needs to be discussed and assembled so that healthcare and workforce planners can rapidly obtain information to appropriately allocate resources.

Neutralizing monoclonal antibody in patients with coronavirus disease 2019: an observational study.

BACKGROUND: Clinical data on patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delta variant are limited, especially on clinical status after the application of antibody therapy. METHODS: We evaluated clinical status in patients with the SARS-CoV-2 delta variant after BRII-196 and BRII-198 treatment in an infectious disease hospital in China. We collected data on clinical symptoms, laboratory tests, radiological characteristics, viral load, anti-SARS-CoV-2 antibodies, treatment, and outcome. RESULTS: In mid-June 2021, 36 patients with delta variant infection were identified in Shenzhen. The most common symptoms at illness onset were cough (30.6%), fever (22.2%), myalgia (16.7%), and fatigue (16.7%). A small number of patients in this study had underlying diseases, including diabetes (5.6%) and hypertension (8.3%). The application of BRII-196 and BRII-198 can rapidly increase anti-SARS-CoV-2 IgG. The median peak IgG levels in the antibody treatment group were 32 times higher than those in the control group (P < 0.001). The time from admission to peak IgG levels in the antibody treatment group (mean: 10.2 days) was significantly shorter than that in the control group (mean: 17.7 days). Chest CT score dropped rapidly after antibody therapy, with a mean duration of 5.74 days from admission to peak levels. CONCLUSION: The results of this study suggest that the application of BRII-196 and BRII-198 antibody therapy improved clinical status in patients with SARS-CoV-2 delta variant infection.

Antigenic sin of wild-type SARS-CoV-2 vaccine shapes poor cross-neutralization of BA.4/5/2.75 subvariants in BA.2 breakthrough infections.

With declining SARS-CoV-2-specific antibody titers and increasing numbers of spike mutations, the ongoing emergence of Omicron subvariants causes serious challenges to current vaccination strategies. BA.2 breakthrough infections have occurred in people who have received the wild-type vaccines, including mRNA, inactivated, or recombinant protein vaccines. Here, we evaluate the antibody evasion of recently emerged subvariants BA.4/5 and BA.2.75 in two inactivated vaccine-immunized cohorts with BA.2 breakthrough infections. Compared with the neutralizing antibody titers against BA.2, marked reductions are observed against BA.2.75 in both 2-dose and 3-dose vaccine groups. In addition, although BA.2 breakthrough infections induce a certain cross-neutralization capacity against later Omicron subvariants, the original antigenic sin phenomenon largely limits the improvement of variant-specific antibody response. These findings suggest that BA.2 breakthrough infections seem unable to provide sufficient antibody protection against later subvariants such as BA.2.75 in the current immunization background with wild-type vaccines.

Healthy outcomes of patients with COVID-19 two years after the infection: a prospective cohort study.

The long-term effect of coronavirus disease 2019 (COVID-19) has been rarely known. This study aimed to investigate healthy outcomes of COVID-19 survivors up to 2 years after the infection. A total of 155 COVID-19 patients, who were discharged from Shenzhen Third People's Hospital from February 2020 to April 2020, were enrolled and followed up until March 4, 2022. COVID-19 survivors received questionnaires of long COVID symptoms and psychological symptoms, pulmonary function tests, chest computed tomography (CT) scans and routine laboratory tests. Two years after infection, 36.6% of patients had at least one symptom of long COVID. Vision impairment and fatigue were the most common symptom. 35.0% of participants still had at least one psychological symptom of anxiety, depression, post-traumatic stress symptoms, and sleep difficulties. Radiographic abnormalities were presented in 50.7% of patients, with the most common features of fibrosis-like lesions and residual ground-glass opacity. Diffuse dysfunction (24.0%) was the main abnormalities of pulmonary function tests. Most laboratory parameters returned to normal range, while persistent abnormalities in kidney and liver function test were observed in a subset of participants after discharge. Two years after COVID-19 infection, persistent symptoms of long COVID and psychological symptoms, as well as abnormalities in pulmonary function tests and CT, were still common in a subset of recovering individuals. These findings were limited by the lack of a healthy control group and pre-COVID assessments, which should be confirmed by further large-scale studies.

Clinical status of patients 1 year after hospital discharge following recovery from COVID-19: a prospective cohort study.

BACKGROUND: The long-term clinical status of coronavirus disease 2019 (COVID-19) in recovered patients remains largely unknown. This prospective cohort study evaluated clinical status of COVID-19 and explored the associated risk factors. METHODS: At the outpatient visit, patients underwent routine blood tests, physical examinations, pulmonary function tests, 6-min walk test, high-resolution computed tomography (CT) of the chest, and extrapulmonary organ function tests. RESULTS: 230 patients were analyzed. Half (52.7%) reported at least one symptom, most commonly fatigue (20.3%) and sleep difficulties (15.8%). Anxiety (8.2%), depression (11.3%), post-traumatic symptoms (10.3%), and sleep disorders (26.3%) were also reported. Diffusion impairments were found in 35.4% of the patients. Abnormal chest CT scans were present in 63.5% of the patients, mainly reticulation and ground-glass opacities. Further, a persistent decline in kidney function was observed after discharge. SARS-CoV-2-specific antibodies of IgA, IgG, and IgM were positive in 56.4%, 96.3%, and 15.2% of patients, respectively. Multivariable logistic regression showed that disease severity, age, and sex were closely related to patient recovery. CONCLUSIONS: One year after hospital discharge, patients recovered from COVID-19 continued to experience both pulmonary and extrapulmonary dysfunction. While paying attention to pulmonary manifestations of COVID-19, follow-up studies on extrapulmonary manifestations should be strengthened.

12-Month Post-Discharge Liver Function Test Abnormalities Among Patients With COVID-19: A Single-Center Prospective Cohort Study.

Objective: The longitudinal effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the liver are unknown. This study aimed to characterize dynamic changes in liver function test abnormalities in patients with COVID-19 at the acute phase and recovery phase. Methods: A prospective cohort study involved patients with COVID-19 who were admitted to Shenzhen Third People's Hospital between January 11, 2020, and April 27, 2020. Patients underwent liver function tests at hospitalization and at the outpatient visit at the 1-month, 3-month, 6-month, and 12-month follow-ups. Results: Among 461 patients, 28.4% of patients had any kind of liver function tests abnormality at admission, manifested as elevated ALT (13.0%), AST (17.6%), and GGT (15.8%) levels. The trajectory analysis indicated a marked improvement in liver function after discharge, with any kind of liver function test abnormalities of 25.1% at 1 month, 13.2% at 3 months, 16.7% at 6 months, and 13.2% at 12 months after discharge. Persistent liver function abnormalities were observed in patients with pre-existing conditions during follow-up. A significantly higher prevalence of ultrasound determined fatty liver disease was found in those patients with more frequent LFT abnormalities at follow-up. Conclusion: In this study of patients with COVID-19, liver damage in COVID-19 was usually temporary and could return to normal at the end of the 12-month follow-up.

Pulmonary Sequelae in Patients After Recovery From Coronavirus Disease 2019: A Follow-Up Study With Chest CT.

Objective: The pulmonary sequelae of coronavirus disease 2019 (COVID-19) have not been comprehensively evaluated. We performed a follow-up study analyzing chest computed tomography (CT) findings of COVID-19 patients at 3 and 6 months after hospital discharge. Methods: Between February 2020 and May 2020, a total of 273 patients with COVID-19 at the Shenzhen Third People's Hospital were recruited and followed for 6 months after discharge. Chest CT scanning was performed with the patient in the supine position at end-inspiration. A total of 957 chest CT scans was obtained at different timepoints. A semi-quantitative score was used to assess the degree of lung involvement. Results: Most chest CT scans showed bilateral lung involvement with peripheral location at 3 and 6 months follow-up. The most common CT findings were ground-glass opacity and parenchymal band, which were found in 136 (55.3%) and 94 (38.2%) of the 246 patients at 3 months follow-up, and 82 (48.2%) and 76 (44.7%) of 170 patients at 6 months follow-up, respectively. The number of lobes involved and the total CT severity score declined over time. The total CT score gradually increased with the increasement of disease severity at both 3 months follow-up (trend test P < 0.001) and 6 months follow-up (trend test P < 0.001). Patients with different disease severity represented diverse CT patterns over time. Conclusions: The most common CT findings were ground-glass opacity and parenchymal bands at the 3 and 6 months follow-up. Patients with different disease severity represent diverse CT manifestations, indicating the necessary for long-term follow-up monitoring of patients with severe and critical conditions.

The Transient IFN Response and the Delay of Adaptive Immunity Feature the Severity of COVID-19.

COVID-19 patients show heterogeneous and dynamic immune features which determine the clinical outcome. Here, we built a single-cell RNA sequencing (scRNA-seq) dataset for dissecting these complicated immune responses through a longitudinal survey of COVID-19 patients with various categories of outcomes. The data reveals a highly fluctuating peripheral immune landscape in severe COVID-19, whereas the one in asymptomatic/mild COVID-19 is relatively steady. Then, the perturbed immune landscape in peripheral blood returned to normal state in those recovered from severe COVID-19. Importantly, the imbalance of the excessively strong innate immune response and delayed adaptive immunity in the early stage of viral infection accelerates the progression of the disease, indicated by a transient strong IFN response and weak T/B-cell specific response. The proportion of abnormal monocytes appeared early and rose further throughout the severe disease. Our data indicate that a dynamic immune landscape is associated with the progression and recovery of severe COVID-19, and have provided multiple immune biomarkers for early warning of severe COVID-19.

Three-Month Pulmonary Function and Radiological Outcomes in COVID-19 Survivors: A Longitudinal Patient Cohort Study.

BACKGROUND: This study aimed to investigate pulmonary function and radiological outcomes in a group of coronavirus disease 2019 (COVID-19) survivors. METHODS: One hundred seventy-two COVID-19 survivors in a follow-up clinic in a referral hospital underwent high-resolution computed tomography (CT) of the thorax and pulmonary function at 3 months after hospital discharge. RESULTS: The median duration from hospital discharge to radiological and pulmonary function test (interquartile range) was 90 (88-95) days. Abnormal pulmonary function was found in 11 (6.40%) patients, and abnormal small airway function (FEF25-75%) in 12 (6.98%). Six (3.49%) patients had obstructive ventilation impairment, and 6 (3.49%) had restrictive ventilatory impairment. No significant differences in lung function parameters were observed between the nonsevere and severe groups. Of 142 COVID-19 patients who underwent CT scan, 122 (85.91%) showed residual CT abnormalities and 52 (36.62%) showed chronic and fibrotic changes. The ground-glass opacities absorption in the lungs of severe cases was less satisfactory than that of nonsevere patients. The severe patients had higher CT scores than the nonsevere cases (2.00 vs 0.00; P < .001). CONCLUSIONS: Of the COVID-19 survivors in our study, 6.40% still presented pulmonary function abnormality 3 months after discharge, which did not vary by disease severity during hospitalization; 85.91% of patients had abnormalities on chest CT, with fibrous stripes and ground-glass opacities being the most common patterns.

Metabolic Defects of Peripheral T Cells in COVID-19 Patients.

The relatively low partial pressure of oxygen, reduced oxygen saturation, and aberrant plasma metabolites in COVID-19 may alter energy metabolism in peripheral immune cells. However, little is known regarding the immunometabolic defects of T cells in COVID-19 patients, which may contribute to the deregulated immune functions of these cells. In this study, we longitudinally characterized the metabolic profiles of resting and activated T cells from acutely infected and convalescent COVID-19 patients by flow cytometry and confirmed the metabolic profiles with a Seahorse analyzer. Non-COVID-19 and healthy subjects were enrolled as controls. We found that ex vivo T cells from acutely infected COVID-19 patients were highly activated and apoptotic and displayed more extensive mitochondrial metabolic dysfunction, especially cells in CD8+ T cell lineages, than those from convalescent COVID-19 patients or healthy controls, but slightly disturbed mitochondrial metabolic activity was observed in non-COVID-19 patients. Importantly, plasma IL-6 and C-reactive protein (CRP) levels positively correlated with mitochondrial mass and negatively correlated with fatty acid uptake in T cells from COVID-19 patients. Additionally, compared with those from healthy controls, in vitro-activated T cells from acutely infected COVID-19 patients showed signs of lower glycolysis, a reduced glycolytic capacity, and a decreased glycolytic reserve, accompanied by lower activation of mTOR signaling. Thus, newly identified defects in T cell mitochondrial metabolic functions and metabolic reprogramming upon activation might contribute to immune deficiency in COVID-19.

Early Viral Clearance and Antibody Kinetics of COVID-19 Among Asymptomatic Carriers.

Asymptomatic carriers contribute to the spread of Coronavirus Disease 2019 (COVID-19), but their clinical characteristics, viral kinetics, and antibody responses remain unclear. A total of 56 COVID-19 patients without symptoms at admission and 19 age-matched symptomatic patients were enrolled. RNA of SARS-CoV-2 was tested using transcriptase quantitative PCR, and the total antibodies (Ab), IgG, IgA, and IgM against the SARS-CoV-2 were tested using Chemiluminescence Microparticle Immuno Assay. Among 56 patients without symptoms at admission, 33 cases displayed symptoms and 23 remained asymptomatic throughout the follow-up period. 43.8% of the asymptomatic carriers were children and none of the asymptomatic cases had recognizable changes in C-reactive protein or interleukin-6, except one 64-year-old patient. The initial threshold cycle value of nasopharyngeal SARS-CoV-2 in asymptomatic carriers was similar to that in pre-symptomatic and symptomatic patients, but the positive viral nucleic acid detection period of asymptomatic carriers (9.63 days) was shorter than pre-symptomatic patients (13.6 days). There were no obvious differences in the seropositive conversion rate of total Ab, IgG, and IgA among the three groups, though the rates of IgM varied largely. The average peak IgG and IgM COI of asymptomatic cases was 3.5 and 0.8, respectively, which is also lower than those in symptomatic patients with peaked IgG and IgM COI of 4.5 and 2.4 (p < 0.05). Young COVID-19 patients seem to be asymptomatic cases with early clearance of SARS-CoV-2 and low levels of IgM generation but high total Ab, IgG, and IgA. Our findings provide empirical information for viral clearance and antibody kinetics of asymptomatic COVID-19 patients.

Early Virus Clearance and Delayed Antibody Response in a Case of Coronavirus Disease 2019 (COVID-19) With a History of Coinfection With Human Immunodeficiency Virus Type 1 and Hepatitis C Virus.

The effect of host immune status on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains unknown. Here, we report the first case of coronavirus disease 2019 (COVID-19) with human immunodeficiency virus type 1 (HIV-1)/hepatitis C virus coinfection, who showed a persistently negative SARS-CoV-2 RNA test but delayed antibody response in the plasma. This case highlights the influence of HIV-1-induced immune dysfunction on early SARS-CoV-2 clearance.

Antibody Responses to SARS-CoV-2 in Patients With Novel Coronavirus Disease 2019.

BACKGROUND: The novel coronavirus SARS-CoV-2 is a newly emerging virus. The antibody response in infected patients remains largely unknown, and the clinical value of antibody testing has not been fully demonstrated. METHODS: 173 patients with SARS-CoV-2 infection were enrolled. Their serial plasma samples (n = 535) collected during hospitalization were tested for total antibodies (Ab), IgM, and IgG against SARS-CoV-2. The dynamics of antibodies with disease progress were analyzed. RESULTS: Among 173 patients, the seroconversion rates for Ab, IgM, and IgG were 93.1%, 82.7%, and 64.7%, respectively. The reason for the negative antibody findings in 12 patients might be due to the lack of blood samples at the later stage of illness. The median seroconversion times for Ab, IgM, and then IgG were days 11, 12, and 4, respectively. The presence of antibodies was <40% among patients within 1 week of onset, and rapidly increased to 100.0% (Ab), 94.3% (IgM), and 79.8% (IgG) by day 15 after onset. In contrast, RNA detectability decreased from 66.7% (58/87) in samples collected before day 7 to 45.5% (25/55) during days 15-39. Combining RNA and antibody detection significantly improved the sensitivity of pathogenic diagnosis for COVID-19 (P < .001), even in the early phase of 1 week from onset (P = .007). Moreover, a higher titer of Ab was independently associated with a worse clinical classification (P = .006). CONCLUSIONS: Antibody detection offers vital clinical information during the course of SARS-CoV-2 infection. The findings provide strong empirical support for the routine application of serological testing in the diagnosis and management of COVID-19 patients.