Effect of Corticosteroids on Long-term Humoral and Memory T-Cell Responses in Follow-up Visit of Hospitalized Patients With COVID-19.

BACKGROUND: Corticosteroids have beneficial effects in improving outcomes in hospitalized patients with severe COVID-19 by suppressing excessive immune responses. However, the effect of corticosteroids on the humoral and T-cell responses of survivors of COVID-19 1 year after infection remains uncertain because it relates to the extent of immediate, antigen-specific defense provided by protective memory. RESEARCH QUESTION: What is the effect of corticosteroids on long-term humoral and T-cell immune responses? STUDY DESIGN AND METHODS: In this retrospective cohort study conducted at a single center, we analyzed data from a cohort who had survived COVID-19 to compare the 1-year seropositivity and titer changes in neutralizing antibodies (NAbs) and SARS-CoV-2-specific antibodies. Additionally, we evaluated the magnitude and rate of SARS-CoV-2-specific T-cell response in individuals who received corticosteroids during hospitalization and those who did not. RESULTS: Our findings indicated that corticosteroids do not statistically influence the kinetics or seropositive rate of NAbs against the Wuhan strain of SARS-CoV-2 from 6 months to 1 year. However, subgroup analysis revealed a numerical increase of absolute NAbs titers, from 20.0 to 28.2, in categories where long-term (> 15 days) and high-dose (> 560 mg) corticosteroids are administered. Similarly, corticosteroids showed no significant effect on nucleoprotein and receptor-binding domain IgG at 1 year, except for spike protein IgG (ß, 0.08; 95% CI, 0.04-0.12), which demonstrated a delayed decline of titers. Regarding T-cell immunity, corticosteroids did not affect the rate or magnitude of T-cell responses significantly. However, functional assessment of memory T cells revealed higher interferon-γ responses in CD4 (ß, 0.61; 95% CI, 0.10-1.12) and CD8 (ß, 0.63; 95% CI, 0.11-1.15) memory T cells in the corticosteroids group at 1 year. INTERPRETATION: Based on our findings, short-term and low-dose corticosteroid therapy during hospitalization does not have a significant effect on long-term humoral kinetics or the magnitude and rate of memory T-cell responses to SARS-CoV-2 antigens. However, the potential harmful effects of long-term and high-dose corticosteroid use on memory immune responses require further investigation.

Residual Immunity from Smallpox Vaccination and Possible Protection from Mpox, China.

Among persons born in China before 1980 and tested for vaccinia virus Tiantan strain (VVT), 28.7% (137/478) had neutralizing antibodies, 71.4% (25/35) had memory B-cell responses, and 65.7% (23/35) had memory T-cell responses to VVT. Because of cross-immunity between the viruses, these findings can help guide mpox vaccination strategies in China.

Durability and cross-reactive immune memory to SARS-CoV-2 in individuals 2 years after recovery from COVID-19: a longitudinal cohort study.

BACKGROUND: SARS-CoV-2-specific adaptive immunity more than 1 year after initial infection has not been well characterised. The aim of this study was to investigate the durability and cross-reactivity of immunological memory acquired from natural infection against SARS-CoV-2 in individuals recovered from COVID-19 2 years after infection. METHODS: In this longitudinal cohort study, we recruited patients who had recovered from laboratory-confirmed COVID-19 and were discharged from Jinyintan Hospital (Wuhan, China) between Jan 7 and May 29, 2020. We carried out three successive follow-ups between June 16 and Sept 3, 2020 (6 months), Dec 16, 2020, and Feb 7, 2021 (1 year), and Nov 16, 2021, and Jan 10, 2022 (2 years), in which blood samples were taken. We included participants who did not have re-infection or receive a SARS-CoV-2 vaccination (infected-unvaccinated), and participants who received one to three doses of inactivated vaccine 1-2 years after infection (infected-vaccinated). We evaluated the presence of IgG antibodies, neutralising antibodies, and memory B-cell and memory T-cell responses against the prototype strain and delta and omicron variants. FINDINGS: In infected-unvaccinated participants, neutralising antibody titres continually declined from 6-month to 2-year follow-up visits, with a half-life of about 141·2 days. Neutralising antibody responses to omicron sublineages (BA.1, BA.1.1, BA.2, BA.4/5, BF.7, BQ.1, and XBB) were poor. Memory B-cell responses to the prototype strain were retained at 2 years and presented cross-reactivity to the delta and omicron BA.1 variants. The magnitude of interferon γ and T-cell responses to SARS-CoV-2 were not significantly different between 1 year and 2 years after infection. Multifunctional T-cell responses against SARS-CoV-2 spike protein and nucleoprotein were detected in most participants. Recognition of the BA.1 variant by memory T cells was not affected in most individuals. The antibody titres and the frequencies of memory B cells, but not memory T cells, increased in infected-vaccinated participants after they received the inactivated vaccine. INTERPRETATION: This study improves the understanding of the duration of SARS-CoV-2-specific immunity without boosting, which has implications for the design of vaccination regimens and programmes. Our data suggest that memory T-cell responses primed by initial viral infection remain highly cross-reactive after 2 years. With the increasing emergence of variants, effective vaccines should be introduced to boost neutralising antibody and overall T-cell responses to newly emerged SARS-CoV-2 variants. FUNDING: Chinese Academy of Medical Sciences, National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities for Peking Union Medical College, Beijing Natural Science Foundation, UK Medical Research Council.

6-month consequences of COVID-19 in patients discharged from hospital: a cohort study.

BACKGROUND: The long-term health consequences of COVID-19 remain largely unclear. The aim of this study was to describe the long-term health consequences of patients with COVID-19 who have been discharged from hospital and investigate the associated risk factors, in particular disease severity. METHODS: We did an ambidirectional cohort study of patients with confirmed COVID-19 who had been discharged from Jin Yin-tan Hospital (Wuhan, China) between Jan 7 and May 29, 2020. Patients who died before follow-up; patients for whom follow-up would be difficult because of psychotic disorders, dementia, or readmission to hospital; those who were unable to move freely due to concomitant osteoarthropathy or immobile before or after discharge due to diseases such as stroke or pulmonary embolism; those who declined to participate; those who could not be contacted; and those living outside of Wuhan or in nursing or welfare homes were all excluded. All patients were interviewed with a series of questionnaires for evaluation of symptoms and health-related quality of life, underwent physical examinations and a 6-min walking test, and received blood tests. A stratified sampling procedure was used to sample patients according to their highest seven-category scale during their hospital stay as 3, 4, and 5-6, to receive pulmonary function test, high resolution CT of the chest, and ultrasonography. Enrolled patients who had participated in the Lopinavir Trial for Suppression of SARS-CoV-2 in China received SARS-CoV-2 antibody tests. Multivariable adjusted linear or logistic regression models were used to evaluate the association between disease severity and long-term health consequences. FINDINGS: In total, 1733 of 2469 discharged patients with COVID-19 were enrolled after 736 were excluded. Patients had a median age of 57·0 years (IQR 47·0-65·0) and 897 (52%) were male and 836 (48%) were female. The follow-up study was done from June 16 to Sept 3, 2020, and the median follow-up time after symptom onset was 186·0 days (175·0-199·0). Fatigue or muscle weakness (52%, 855 of 1654) and sleep difficulties (26%, 437 of 1655) were the most common symptoms. Anxiety or depression was reported among 23% (367 of 1616) of patients. The proportions of 6-min walking distance less than the lower limit of the normal range were 17% for those at severity scale 3, 13% for severity scale 4, and 28% for severity scale 5-6. The corresponding proportions of patients with diffusion impairment were 22% for severity scale 3, 29% for scale 4, and 56% for scale 5-6, and median CT scores were 3·0 (IQR 2·0-5·0) for severity scale 3, 4·0 (3·0-5·0) for scale 4, and 5·0 (4·0-6·0) for scale 5-6. After multivariable adjustment, patients showed an odds ratio (OR) of 1·61 (95% CI 0·80-3·25) for scale 4 versus scale 3 and 4·60 (1·85-11·48) for scale 5-6 versus scale 3 for diffusion impairment; OR 0·88 (0·66-1·17) for scale 4 versus scale 3 and OR 1·76 (1·05-2·96) for scale 5-6 versus scale 3 for anxiety or depression, and OR 0·87 (0·68-1·11) for scale 4 versus scale 3 and 2·75 (1·61-4·69) for scale 5-6 versus scale 3 for fatigue or muscle weakness. Of 94 patients with blood antibodies tested at follow-up, the seropositivity (96·2% vs 58·5%) and median titres (19·0 vs 10·0) of the neutralising antibodies were significantly lower compared with at the acute phase. 107 of 822 participants without acute kidney injury and with an estimated glomerular filtration rate (eGFR) of 90 mL/min per 1·73 m2 or more at acute phase had eGFR less than 90 mL/min per 1·73 m2 at follow-up. INTERPRETATION: At 6 months after acute infection, COVID-19 survivors were mainly troubled with fatigue or muscle weakness, sleep difficulties, and anxiety or depression. Patients who were more severely ill during their hospital stay had more severe impaired pulmonary diffusion capacities and abnormal chest imaging manifestations, and are the main target population for intervention of long-term recovery. FUNDING: National Natural Science Foundation of China, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, National Key Research and Development Program of China, Major Projects of National Science and Technology on New Drug Creation and Development of Pulmonary Tuberculosis, and Peking Union Medical College Foundation.

Omicron BA.1 breakthrough infections in inactivated COVID-19 vaccine recipients induced distinct pattern of antibody and T cell responses to different Omicron sublineages.

The adaptive immunity against SARS-CoV-2 prototype strain and Omicron sublineages induced by BA.1 breakthrough infection in vaccinees of inactivated COVID-19 vaccines have not been well characterized. Here, we report that BA.1 breakthrough infection induced mucosal sIgA and resulted in higher IgG titers against prototype strain and Omicron sublineages in vaccinees than in vaccine naïve-infected individuals. BA.1 breakthrough infection boosted antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis to prototype strain and BA.1, BA.1.1, BA.2, BA.2.12.1, and BA.2.75 but not BA.4/5 and induced neutralization against prototype strain and BA.1, BA.1.1, BA.2, BA.2.12.1, BA.2.75, and BA.4/5 but not BF.7, BQ.1, and XBB. In total, BA.1 breakthrough infection individuals produced less extensive sIgA, plasma IgG and NAb responses against Omicron sublineages compared with those against prototype strain. Further, BA.1 breakthrough infection induced recall B cell response to prototype strain and Omicron variant, primarily targeting memory B cells producing conserved epitopes. Memory T cell responses against Omicron is largely preserved. Individuals with vaccine booster did not induce more beneficial immune responses to Omicron sublineages upon BA.1 breakthrough infection than those with primary vaccine dose only. The breakthrough infection individuals produced stronger adaptive immunity than those of inactivated vaccine-healthy individuals. These data have important implications for understanding the vaccine effectiveness and adaptive immunity to breakthrough infection in individuals fully immunized with inactivated vaccines. Omicron sublineages, especially for those emerged after BA.4/5 strain, evade NAb responses induced by BA.1 breakthrough infection. It is urgent to optimize the vaccine immunogen design and formulations to SARS-CoV-2 variants.

Humoral responses after inactivated COVID-19 vaccination in individuals with and without prior SARS-CoV-2 infection: A prospective cohort study.

We evaluated and compared humoral immune responses after inactivated coronavirus disease 2019 (COVID-19) vaccination among naïve individuals, asymptomatically infected individuals, and recovered patients with varying severity. In this multicenter, prospective cohort study, blood samples from 666 participants were collected before and after 2 doses of inactivated COVID-19 vaccination. Among 392 severe acute respiratory syndrome coronavirus 2-naïve individuals, the seroconversion rate increased significantly from 51.8% (median antispike protein pan-immunoglobulins [S-Igs] titer: 0.8 U/ml) after the first dose to 96% (median S-Igs titer: 79.5 U/ml) after the second dose. Thirty-two percent of naïve individuals had detectable neutralizing antibodies (NAbs) against the original strain but all of them lost neutralizing activity against the Omicron variant. In 274 individuals with natural infection, humoral immunity was significantly improved after a single vaccine dose, with median S-Igs titers of 596.7, 1176, 1086.5, and 1828 U/ml for asymptomatic infections, mild cases, moderate cases, and severe/critical cases, respectively. NAb titers also improved significantly. However, the second dose did not substantially increase antibody levels. Although a booster dose is needed for those without infection, our findings indicate that recovered patients should receive only a single dose of the vaccine, regardless of the clinical severity, until there is sufficient evidence to confirm the benefits of a second dose.

Health outcomes in people 2 years after surviving hospitalisation with COVID-19: a longitudinal cohort study.

BACKGROUND: With the ongoing COVID-19 pandemic, growing evidence shows that a considerable proportion of people who have recovered from COVID-19 have long-term effects on multiple organs and systems. A few longitudinal studies have reported on the persistent health effects of COVID-19, but the follow-up was limited to 1 year after acute infection. The aim of our study was to characterise the longitudinal evolution of health outcomes in hospital survivors with different initial disease severity throughout 2 years after acute COVID-19 infection and to determine their recovery status. METHODS: We did an ambidirectional, longitudinal cohort study of individuals who had survived hospitalisation with COVID-19 and who had been discharged from Jin Yin-tan Hospital (Wuhan, China) between Jan 7 and May 29, 2020. We measured health outcomes 6 months (June 16-Sept 3, 2020), 12 months (Dec 16, 2020-Feb 7, 2021), and 2 years (Nov 16, 2021-Jan 10, 2022) after symptom onset with a 6-min walking distance (6MWD) test, laboratory tests, and a series of questionnaires on symptoms, mental health, health-related quality of life (HRQoL), return to work, and health-care use after discharge. A subset of COVID-19 survivors received pulmonary function tests and chest imaging at each visit. Age-matched, sex-matched, and comorbidities-matched participants without COVID-19 infection (controls) were introduced to determine the recovery status of COVID-19 survivors at 2 years. The primary outcomes included symptoms, modified British Medical Research Council (mMRC) dyspnoea scale, HRQoL, 6MWD, and return to work, and were assessed in all COVID-19 survivors who attended all three follow-up visits. Symptoms, mMRC dyspnoea scale, and HRQoL were also assessed in controls. FINDINGS: 2469 patients with COVID-19 were discharged from Jin Yin-tan Hospital between Jan 7 and May 29, 2020. 1192 COVID-19 survivors completed assessments at the three follow-up visits and were included in the final analysis, 1119 (94%) of whom attended the face-to-face interview 2 years after infection. The median age at discharge was 57·0 years (48·0-65·0) and 551 (46%) were women. The median follow-up time after symptom onset was 185·0 days (IQR 175·0-197·0) for the visit at 6 months, 349·0 days (337·0-360·0) for the visit at 12 months, and 685·0 days (675·0-698·0) for the visit at 2 years. The proportion of COVID-19 survivors with at least one sequelae symptom decreased significantly from 777 (68%) of 1149 at 6 months to 650 (55%) of 1190 at 2 years (p<0·0001), with fatigue or muscle weakness always being the most frequent. The proportion of COVID-19 survivors with an mMRC score of at least 1 was 168 (14%) of 1191 at 2 years, significantly lower than the 288 (26%) of 1104 at 6 months (p<0·0001). HRQoL continued to improve in almost all domains, especially in terms of anxiety or depression: the proportion of individuals with symptoms of anxiety or depression decreased from 256 (23%) of 1105 at 6 months to 143 (12%) 1191 at 2 years (p<0·0001). The proportion of individuals with a 6MWD less than the lower limit of the normal range declined continuously in COVID-19 survivors overall and in the three subgroups of varying initial disease severity. 438 (89%) of 494 COVID-19 survivors had returned to their original work at 2 years. Survivors with long COVID symptoms at 2 years had lower HRQoL, worse exercise capacity, more mental health abnormality, and increased health-care use after discharge than survivors without long COVID symptoms. COVID-19 survivors still had more prevalent symptoms and more problems in pain or discomfort, as well as anxiety or depression, at 2 years than did controls. Additionally, a significantly higher proportion of survivors who had received higher-level respiratory support during hospitalisation had lung diffusion impairment (43 [65%] of 66 vs 24 [36%] of 66, p=0·0009), reduced residual volume (41 [62%] vs 13 [20%], p<0·0001), and total lung capacity (26 [39%] vs four [6%], p<0·0001) than did controls. INTERPRETATION: Regardless of initial disease severity, COVID-19 survivors had longitudinal improvements in physical and mental health, with most returning to their original work within 2 years; however, the burden of symptomatic sequelae remained fairly high. COVID-19 survivors had a remarkably lower health status than the general population at 2 years. The study findings indicate that there is an urgent need to explore the pathogenesis of long COVID and develop effective interventions to reduce the risk of long COVID.

SARS-CoV-2-specific antibody and T-cell responses 1 year after infection in people recovered from COVID-19: a longitudinal cohort study.

Background: The memory immune response is crucial for preventing reinfection or reducing disease severity. However, the robustness and functionality of the humoral and T-cell response to SARS-CoV-2 remains unknown 12 months after initial infection. The aim of this study is to investigate the durability and functionality of the humoral and T-cell response to the original SARS-CoV-2 strain and variants in recovered patients 12 months after infection. Methods: In this longitudinal cohort study, we recruited participants who had recovered from COVID-19 and who were discharged from the Wuhan Research Center for Communicable Disease Diagnosis and Treatment at the Chinese Academy of Medical Sciences, Wuhan, China, between Jan 7 and May 29, 2020. Patients received a follow-up visit between Dec 16, 2020, and Jan 27, 2021. We evaluated the presence of IgM, IgA, and IgG antibodies against the SARS-CoV-2 nucleoprotein, Spike protein, and the receptor-binding domain 12 months after initial infection, using ELISA. Neutralising antibodies against the original SARS-CoV-2 strain, and the D614G, beta (B.1.351), and delta (B.1.617.2) variants were analysed using a microneutralisation assay in a subset of plasma samples. We analysed the magnitude and breadth of the SARS-CoV-2-specific memory T-cell responses using the interferon γ (IFNγ) enzyme-linked immune absorbent spot (ELISpot) assay and intracellular cytokine staining (ICS) assay. The antibody response and T-cell response (ie, IFN-γ, interleukin-2 [IL-2], and tumour necrosis factor α [TNFα]) were analysed by age and disease severity. Antibody titres were also analysed according to sequelae symptoms. Findings: We enrolled 1096 patients, including 289 (26·4%) patients with moderate initial disease, 734 (67·0%) with severe initial disease, and 73 (6·7%) with critical initial disease. Paired plasma samples were collected from 141 patients during the follow-up visits for the microneutralisation assay. PBMCs were collected from 92 of 141 individuals at the 12-month follow-up visit, of which 80 were analysed by ELISpot and 92 by ICS assay to detect the SARS-CoV-2-specific memory T-cell responses. N-IgG (899 [82·0%]), S-IgG (1043 [95·2%]), RBD-IgG (1032 [94·2%]), and neutralising (115 [81·6%] of 141) antibodies were detectable 12 months after initial infection in most individuals. Neutralising antibodies remained stable 6 and 12 months after initial infection in most individuals younger than 60 years. Multifunctional T-cell responses were detected for all SARS-CoV-2 viral proteins tested. There was no difference in the magnitude of T-cell responses or cytokine profiles in individuals with different symptom severity. Moreover, we evaluated both antibody and T-cell responses to the D614G, beta, and delta viral strains. The degree of reduced in-vitro neutralising antibody responses to the D614G and delta variants, but not to the beta variant, was associated with the neutralising antibody titres after SARS-CoV-2 infection. We also found poor neutralising antibody responses to the beta variant; 83 (72·2%) of 115 patients showed no response at all. Moreover, the neutralising antibody titre reduction of the recovered patient plasma against the delta variant was similar to that of the D614G variant and lower than that of the beta variant. By contrast, T-cell responses were cross-reactive to the beta variant in most individuals. Importantly, T-cell responses could be detected in all individuals who had lost the neutralising antibody response to SARS-CoV-2 12 months after the initial infection. Interpretation: SARS-CoV-2-specific neutralising antibody and T-cell responses were retained 12 months after initial infection. Neutralising antibodies to the D614G, beta, and delta viral strains were reduced compared with those for the original strain, and were diminished in general. Memory T-cell responses to the original strain were not disrupted by new variants. This study suggests that cross-reactive SARS-CoV-2-specific T-cell responses could be particularly important in the protection against severe disease caused by variants of concern whereas neutralising antibody responses seem to reduce over time. Funding: Chinese Academy of Medical Sciences, National Natural Science Foundation, and UK Medical Research Council.

Cross-reactive antibody against human coronavirus OC43 spike protein correlates with disease severity in COVID-19 patients: a retrospective study.

Seasonal human coronaviruses (HCoVs) including HCoV-229E, -OC43, -NL63, and -HKU1 widely spread in global human populations. However, the relevance of humoral response against seasonal HCoVs to COVID-19 pathogenesis is elusive. In this study, we profiled the temporal changes of IgG antibody against spike proteins (S-IgG) of SARS-CoV-2 and seasonal HCoVs in 838 plasma samples collected from 344 COVID-19 patients. We tested the antigenic cross-reactivities of S protein between SARS-CoV-2 and seasonal HCoVs and evaluated the correlations between the levels of HCoV-OC43 S-IgG and the disease severity in COVID-19 patients. We found that SARS-CoV-2 S-IgG titres mounted until days 22-28, whereas HCoV-OC43 antibody titres increased until days 15-21 and then plateaued until day 46. However, IgG titres against HCoV-NL63, -229E, and -HKU1 showed no significant increase. A two-way cross-reactivity was identified between SARS-CoV-2 and HCoV-OC43. Neutralizing antibodies against SARS-CoV-2 were not detectable in healthy controls who were positive for HCoV-OC43 S-IgG. HCoV-OC43 S-IgG titres were significantly higher in patients with severe disease than those in mild patients at days 1-21 post symptom onset (PSO). Higher levels of HCoV-OC43 S-IgG were also observed in patients requiring mechanical ventilation. At days 1-10 PSO, HCoV-OC43 S-IgG titres correlated to disease severity in the age group over 60. Our data indicate that there is a correlation between cross-reactive antibody against HCoV-OC43 spike protein and disease severity in COVID-19 patients.

Seroprevalence and humoral immune durability of anti-SARS-CoV-2 antibodies in Wuhan, China: a longitudinal, population-level, cross-sectional study.

BACKGROUND: Wuhan was the epicentre of the COVID-19 outbreak in China. We aimed to determine the seroprevalence and kinetics of anti-SARS-CoV-2 antibodies at population level in Wuhan to inform the development of vaccination strategies. METHODS: In this longitudinal cross-sectional study, we used a multistage, population-stratified, cluster random sampling method to systematically select 100 communities from the 13 districts of Wuhan. Households were systematically selected from each community and all family members were invited to community health-care centres to participate. Eligible individuals were those who had lived in Wuhan for at least 14 days since Dec 1, 2019. All eligible participants who consented to participate completed a standardised electronic questionnaire of demographic and clinical questions and self-reported any symptoms associated with COVID-19 or previous diagnosis of COVID-19. A venous blood sample was taken for immunological testing on April 14-15, 2020. Blood samples were tested for the presence of pan-immunoglobulins, IgM, IgA, and IgG antibodies against SARS-CoV-2 nucleocapsid protein and neutralising antibodies were assessed. We did two successive follow-ups between June 11 and June 13, and between Oct 9 and Dec 5, 2020, at which blood samples were taken. FINDINGS: Of 4600 households randomly selected, 3599 families (78·2%) with 9702 individuals attended the baseline visit. 9542 individuals from 3556 families had sufficient samples for analyses. 532 (5·6%) of 9542 participants were positive for pan-immunoglobulins against SARS-CoV-2, with a baseline adjusted seroprevalence of 6·92% (95% CI 6·41-7·43) in the population. 437 (82·1%) of 532 participants who were positive for pan-immunoglobulins were asymptomatic. 69 (13·0%) of 532 individuals were positive for IgM antibodies, 84 (15·8%) were positive for IgA antibodies, 532 (100%) were positive for IgG antibodies, and 212 (39·8%) were positive for neutralising antibodies at baseline. The proportion of individuals who were positive for pan-immunoglobulins who had neutralising antibodies in April remained stable for the two follow-up visits (162 [44·6%] of 363 in June, 2020, and 187 [41·2%] of 454 in October-December, 2020). On the basis of data from 335 individuals who attended all three follow-up visits and who were positive for pan-immunoglobulins, neutralising antibody levels did not significantly decrease over the study period (median 1/5·6 [IQR 1/2·0 to 1/14·0] at baseline vs 1/5·6 [1/4·0 to 1/11·2] at first follow-up [p=1·0] and 1/6·3 [1/2·0 to 1/12·6] at second follow-up [p=0·29]). However, neutralising antibody titres were lower in asymptomatic individuals than in confirmed cases and symptomatic individuals. Although titres of IgG decreased over time, the proportion of individuals who had IgG antibodies did not decrease substantially (from 30 [100%] of 30 at baseline to 26 [89·7%] of 29 at second follow-up among confirmed cases, 65 [100%] of 65 at baseline to 58 [92·1%] of 63 at second follow-up among symptomatic individuals, and 437 [100%] of 437 at baseline to 329 [90·9%] of 362 at second follow-up among asymptomatic individuals). INTERPRETATION: 6·92% of a cross-sectional sample of the population of Wuhan developed antibodies against SARS-CoV-2, with 39·8% of this population seroconverting to have neutralising antibodies. Our durability data on humoral responses indicate that mass vaccination is needed to effect herd protection to prevent the resurgence of the epidemic. FUNDING: Chinese Academy of Medical Sciences & Peking Union Medical College, National Natural Science Foundation, and Chinese Ministry of Science and Technology. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

6-month consequences of COVID-19 in patients discharged from hospital: a cohort study.

BACKGROUND: The long-term health consequences of COVID-19 remain largely unclear. The aim of this study was to describe the long-term health consequences of patients with COVID-19 who have been discharged from hospital and investigate the associated risk factors, in particular disease severity. METHODS: We did an ambidirectional cohort study of patients with confirmed COVID-19 who had been discharged from Jin Yin-tan Hospital (Wuhan, China) between Jan 7, 2020, and May 29, 2020. Patients who died before follow-up, patients for whom follow-up would be difficult because of psychotic disorders, dementia, or re-admission to hospital, those who were unable to move freely due to concomitant osteoarthropathy or immobile before or after discharge due to diseases such as stroke or pulmonary embolism, those who declined to participate, those who could not be contacted, and those living outside of Wuhan or in nursing or welfare homes were all excluded. All patients were interviewed with a series of questionnaires for evaluation of symptoms and health-related quality of life, underwent physical examinations and a 6-min walking test, and received blood tests. A stratified sampling procedure was used to sample patients according to their highest seven-category scale during their hospital stay as 3, 4, and 5-6, to receive pulmonary function test, high resolution CT of the chest, and ultrasonography. Enrolled patients who had participated in the Lopinavir Trial for Suppression of SARS-CoV-2 in China received severe acute respiratory syndrome coronavirus 2 antibody tests. Multivariable adjusted linear or logistic regression models were used to evaluate the association between disease severity and long-term health consequences. FINDINGS: In total, 1733 of 2469 discharged patients with COVID-19 were enrolled after 736 were excluded. Patients had a median age of 57·0 (IQR 47·0-65·0) years and 897 (52%) were men. The follow-up study was done from June 16, to Sept 3, 2020, and the median follow-up time after symptom onset was 186·0 (175·0-199·0) days. Fatigue or muscle weakness (63%, 1038 of 1655) and sleep difficulties (26%, 437 of 1655) were the most common symptoms. Anxiety or depression was reported among 23% (367 of 1617) of patients. The proportions of median 6-min walking distance less than the lower limit of the normal range were 24% for those at severity scale 3, 22% for severity scale 4, and 29% for severity scale 5-6. The corresponding proportions of patients with diffusion impairment were 22% for severity scale 3, 29% for scale 4, and 56% for scale 5-6, and median CT scores were 3·0 (IQR 2·0-5·0) for severity scale 3, 4·0 (3·0-5·0) for scale 4, and 5·0 (4·0-6·0) for scale 5-6. After multivariable adjustment, patients showed an odds ratio (OR) 1·61 (95% CI 0·80-3·25) for scale 4 versus scale 3 and 4·60 (1·85-11·48) for scale 5-6 versus scale 3 for diffusion impairment; OR 0·88 (0·66-1·17) for scale 4 versus scale 3 and OR 1·77 (1·05-2·97) for scale 5-6 versus scale 3 for anxiety or depression, and OR 0·74 (0·58-0·96) for scale 4 versus scale 3 and 2·69 (1·46-4·96) for scale 5-6 versus scale 3 for fatigue or muscle weakness. Of 94 patients with blood antibodies tested at follow-up, the seropositivity (96·2% vs 58·5%) and median titres (19·0 vs 10·0) of the neutralising antibodies were significantly lower compared with at the acute phase. 107 of 822 participants without acute kidney injury and with estimated glomerular filtration rate (eGFR) 90 mL/min per 1·73 m2 or more at acute phase had eGFR less than 90 mL/min per 1·73 m2 at follow-up. INTERPRETATION: At 6 months after acute infection, COVID-19 survivors were mainly troubled with fatigue or muscle weakness, sleep difficulties, and anxiety or depression. Patients who were more severely ill during their hospital stay had more severe impaired pulmonary diffusion capacities and abnormal chest imaging manifestations, and are the main target population for intervention of long-term recovery. FUNDING: National Natural Science Foundation of China, Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, National Key Research and Development Program of China, Major Projects of National Science and Technology on New Drug Creation and Development of Pulmonary Tuberculosis, and Peking Union Medical College Foundation.