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1.
EBioMedicine ; 79: 103986, 2022 May.
Article in English | MEDLINE | ID: covidwho-1778094

ABSTRACT

BACKGROUND: SARS-CoV-2 Omicron variant evades immunity from past infection or vaccination and is associated with a greater risk of reinfection among recovered COVID-19 patients. We assessed the serum neutralizing antibody (NAb) activity against Omicron variant (Omicron NAb) among recovered COVID-19 patients with or without vaccination. METHODS: In this prospective cohort study with 135 recovered COVID-19 patients, we determined the serum NAb titers against ancestral virus or variants using a live virus NAb assay. We used the receiver operating characteristic analysis to determine the optimal cutoff for a commercially-available surrogate NAb assay. FINDINGS: Among recovered COVID-19 patients, the serum live virus geometric mean Omicron NAb titer was statistically significantly higher among BNT162b2 recipients compared to non-vaccinated individuals (85.4 vs 5.6,P < 0.0001). The Omicron seropositive rates in live virus NAb test (NAb titer ≥10) were statistically significantly higher among BNT162b2 (90.6% [29/32];P < 0.0001) or CoronaVac (36.7% [11/30]; P = 0.0115) recipients when compared with non-vaccinated individuals (12.3% [9/73]). Subgroup analysis of CoronaVac recipients showed that the Omicron seropositive rates were higher among individuals with two doses than those with one dose (85.7% vs 21.7%; P = 0.0045). For the surrogate NAb assay, a cutoff of 109.1 AU/ml, which is 7.3-fold higher than the manufacturer's recommended cutoff, could achieve a sensitivity and specificity of 89.5% and 89.8%, respectively, in detecting Omicron NAb. INTERPRETATION: Among individuals with prior COVID-19, one dose of BNT162b2 or two doses of CoronaVac could induce detectable serum Omicron NAb. Our result would be particularly important for guiding vaccine policies in countries with COVID-19 vaccine shortage. FUNDING: Health and Medical Research Fund, Richard and Carol Yu, Michael Tong (see acknowledgments for full list).


Subject(s)
COVID-19 Vaccines , COVID-19 , Antibodies, Blocking , Antibodies, Neutralizing , Antibodies, Viral , BNT162 Vaccine , COVID-19/prevention & control , Humans , Prospective Studies , SARS-CoV-2
2.
SSRN;
Preprint in English | SSRN | ID: ppcovidwho-326165

ABSTRACT

Background: SARS-CoV-2 Omicron variant evades immunity from past infection or vaccination and is associated with a greater risk of reinfection among recovered COVID-19 patients. We assessed the serum neutralizing antibody (NAb) activity against Omicron variant (Omicron NAb) among recovered COVID-19 patients with or without vaccination. Methods: In this prospective cohort study with 135 recovered COVID-19 patients, we determined the serum NAb titers against ancestral virus or variants using a live virus NAb assay. We used the receiver operating characteristic analysis to determine the optimal cutoff for a commercially-available surrogate NAb assay. Findings: Among recovered COVID-19 patients, the serum live virus geometric mean Omicron NAb titer was statistically significantly higher among BNT162b2 recipients compared to non-vaccinated individuals (85.4 vs 5.6, P<0.0001). The Omicron seropositive rates in live virus NAb test (NAb titer ≥10) were statistically significantly higher among BNT162b2 (93.5% [29/32];P<0.0001) or CoronaVac (36.7% [11/30];P=0.0115) recipients when compared with non-vaccinated individuals (12.3% [9/73]). Subgroup analysis of CoronaVac recipients showed that the Omicron seropositive rates were higher among individuals with two doses than those with one dose (85.7% vs 21.7%;P=0.0045). For the surrogate NAb assay, a cutoff of 109.1 AU/ml, which is 7.3-fold higher than the manufacturer’s recommended cutoff, could achieve a sensitivity and specificity of 89.5% and 89.8%, respectively, in detecting Omicron NAb. Interpretation: Among individuals with prior COVID-19, one dose of BNT162b2 and two doses of CoronaVac could induce detectable serum Omicron NAb. Our result would be particularly important for guiding vaccine policies in countries with COVID-19 vaccine shortage. Funding Information: This work was supported by Health and Medical Research Fund, the Food and Health Bureau, The Government of the Hong Kong Special Administrative Region (Ref no.: COVID190124 and COVID1903010 [Project 1]), and donations of Richard Yu and Carol Yu, Shaw Foundation Hong Kong, Michael Seak-Kan Tong, May Tam Mak Mei Yin, Lee Wan Keung Charity Foundation Limited, Hong Kong Sanatorium & Hospital, Respiratory Viral Research Foundation Limited, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund Limited, Chan Yin Chuen Memorial Charitable Foundation, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, the Jessie & George Ho Charitable Foundation, Kai Chong Tong, Tse Kam Ming Laurence, Foo Oi Foundation Limited, Betty Hing-Chu Lee, and Ping Cham So. Declaration of Interests: KYY and KKWT report collaboration with SinoVac and Sinopharm. Other authors declare no conflict of interest.

3.
Lancet Reg Health West Pac ; 10: 100130, 2021 May.
Article in English | MEDLINE | ID: covidwho-1144861

ABSTRACT

BACKGROUND: Viral genomic surveillance is vital for understanding the transmission of COVID-19. In Hong Kong, breakthrough outbreaks have occurred in July (third wave) and November (fourth wave) 2020. We used whole viral genome analysis to study the characteristics of these waves. METHODS: We analyzed 509 SARS-CoV-2 genomes collected from Hong Kong patients between 22nd January and 29th November, 2020. Phylogenetic and phylodynamic analyses were performed, and were interpreted with epidemiological information. FINDINGS: During the third and fourth waves, diverse SARS-CoV-2 genomes were identified among imported infections. Conversely, local infections were dominated by a single lineage during each wave, with 96.6% (259/268) in the third wave and 100% (73/73) in the fourth wave belonging to B.1.1.63 and B.1.36.27 lineages, respectively. While B.1.1.63 lineage was imported 2 weeks before the beginning of the third wave, B.1.36.27 lineage has circulated in Hong Kong for 2 months prior to the fourth wave. During the fourth wave, 50.7% (37/73) of local infections in November was identical to the viral genome from an imported case in September. Within B.1.1.63 or B.1.36.27 lineage in our cohort, the most common non-synonymous mutations occurred at the helicase (nsp13) gene. INTERPRETATION: Although stringent measures have prevented most imported cases from spreading in Hong Kong, a single lineage with low-level local transmission in October and early November was responsible for the fourth wave. A superspreading event or lower temperature in November may have facilitated the spread of the B.1.36.27 lineage.

4.
Emerg Infect Dis ; 27(1): 196-204, 2021 01.
Article in English | MEDLINE | ID: covidwho-993249

ABSTRACT

Initial cases of coronavirus disease in Hong Kong were imported from mainland China. A dramatic increase in case numbers was seen in February 2020. Most case-patients had no recent travel history, suggesting the presence of transmission chains in the local community. We collected demographic, clinical, and epidemiologic data from 50 patients, who accounted for 53.8% of total reported case-patients as of February 28, 2020. We performed whole-genome sequencing to determine phylogenetic relationship and transmission dynamics of severe acute respiratory syndrome coronavirus 2 infections. By using phylogenetic analysis, we attributed the community outbreak to 2 lineages; 1 harbored a common mutation, Orf3a-G251V, and accounted for 88.0% of the cases in our study. The estimated time to the most recent common ancestor of local coronavirus disease outbreak was December 24, 2019, with an evolutionary rate of 3.04 × 10-3 substitutions/site/year. The reproduction number was 1.84, indicating ongoing community spread.


Subject(s)
COVID-19/epidemiology , COVID-19/virology , Disease Outbreaks , Adult , Aged , Aged, 80 and over , COVID-19/transmission , Cluster Analysis , Disease Hotspot , Evolution, Molecular , Female , Hong Kong/epidemiology , Humans , Male , Middle Aged , Mutation , Phylogeny , Phylogeography , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viroporin Proteins/genetics , Whole Genome Sequencing , Young Adult
5.
Clin Microbiol Infect ; 27(9): 1350.e1-1350.e5, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-938847

ABSTRACT

OBJECTIVES: SARS-CoV-2 has evolved rapidly into several genetic clusters. However, data on mutations during the course of infection are scarce. This study aims to determine viral genome diversity in serial samples of COVID-19 patients. METHODS: Targeted deep sequencing of the spike gene was performed on serial respiratory specimens from COVID-19 patients using nanopore and Illumina sequencing. Sanger sequencing was then performed to confirm the single nucleotide polymorphisms. RESULTS: A total of 28 serial respiratory specimens from 12 patients were successfully sequenced using nanopore and Illumina sequencing. A 75-year-old patient with severe disease had a mutation, G22017T, identified in the second specimen. The frequency of G22017T increased from ≤5% (nanopore: 3.8%; Illumina: 5%) from the first respiratory tract specimen (sputum) to ≥60% (nanopore: 67.7%; Illumina: 60.4%) in the second specimen (saliva; collected 2 days after the first specimen). The difference in G22017T frequency was also confirmed by Sanger sequencing. G22017T corresponds to W152L amino acid mutation in the spike protein which was only found in <0.03% of the sequences deposited into a public database. Spike amino acid residue 152 is located within the N-terminal domain, which mediates the binding of a neutralizing antibody. DISCUSSION: A spike protein amino acid mutation W152L located within a neutralizing epitope has appeared naturally in a patient. Our study demonstrated that monitoring of serial specimens is important in identifying hotspots of mutations, especially those occurring at neutralizing epitopes which may affect the therapeutic efficacy of monoclonal antibodies.


Subject(s)
Antibodies, Viral/immunology , COVID-19/virology , Epitopes/genetics , Genetic Variation , Genome, Viral/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Adult , Aged , Antibodies, Neutralizing/immunology , Epitopes/immunology , Female , High-Throughput Nucleotide Sequencing , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Mutation , Nanopore Sequencing , Respiratory System/virology , SARS-CoV-2/genetics , Saliva/virology , Sequence Analysis, RNA , Spike Glycoprotein, Coronavirus/immunology
7.
Science ; 369(6508): 1210-1220, 2020 09 04.
Article in English | MEDLINE | ID: covidwho-704393

ABSTRACT

Coronavirus disease 2019 (COVID-19) represents a global crisis, yet major knowledge gaps remain about human immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We analyzed immune responses in 76 COVID-19 patients and 69 healthy individuals from Hong Kong and Atlanta, Georgia, United States. In the peripheral blood mononuclear cells (PBMCs) of COVID-19 patients, we observed reduced expression of human leukocyte antigen class DR (HLA-DR) and proinflammatory cytokines by myeloid cells as well as impaired mammalian target of rapamycin (mTOR) signaling and interferon-α (IFN-α) production by plasmacytoid dendritic cells. By contrast, we detected enhanced plasma levels of inflammatory mediators-including EN-RAGE, TNFSF14, and oncostatin M-which correlated with disease severity and increased bacterial products in plasma. Single-cell transcriptomics revealed a lack of type I IFNs, reduced HLA-DR in the myeloid cells of patients with severe COVID-19, and transient expression of IFN-stimulated genes. This was consistent with bulk PBMC transcriptomics and transient, low IFN-α levels in plasma during infection. These results reveal mechanisms and potential therapeutic targets for COVID-19.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , COVID-19 , Cytokines/blood , DNA, Bacterial/blood , Dendritic Cells/immunology , Dendritic Cells/metabolism , Female , Flow Cytometry , HLA-DR Antigens/analysis , Humans , Immunity , Immunity, Innate , Immunoglobulins/blood , Immunoglobulins/immunology , Inflammation Mediators/blood , Interferon Type I/metabolism , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/metabolism , Lipopolysaccharides/blood , Male , Myeloid Cells/immunology , Myeloid Cells/metabolism , Pandemics , SARS-CoV-2 , Signal Transduction , Single-Cell Analysis , Systems Biology , TOR Serine-Threonine Kinases/metabolism , Transcription, Genetic , Transcriptome
8.
Immunity ; 53(4): 864-877.e5, 2020 10 13.
Article in English | MEDLINE | ID: covidwho-693493

ABSTRACT

The SARS-CoV-2 pandemic has resulted in millions of infections, yet the role of host immune responses in early COVID-19 pathogenesis remains unclear. By investigating 17 acute and 24 convalescent patients, we found that acute SARS-CoV-2 infection resulted in broad immune cell reduction including T, natural killer, monocyte, and dendritic cells (DCs). DCs were significantly reduced with functional impairment, and ratios of conventional DCs to plasmacytoid DCs were increased among acute severe patients. Besides lymphocytopenia, although neutralizing antibodies were rapidly and abundantly generated in patients, there were delayed receptor binding domain (RBD)- and nucleocapsid protein (NP)-specific T cell responses during the first 3 weeks after symptoms onset. Moreover, acute RBD- and NP-specific T cell responses included relatively more CD4 T cells than CD8 T cells. Our findings provided evidence that impaired DCs, together with timely inverted strong antibody but weak CD8 T cell responses, could contribute to acute COVID-19 pathogenesis and have implications for vaccine development.


Subject(s)
Betacoronavirus/pathogenicity , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Coronavirus Infections/immunology , Dendritic Cells/immunology , Diabetes Mellitus/immunology , Hypertension/immunology , Pneumonia, Viral/immunology , Adult , Aged , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Betacoronavirus/immunology , CD4-Positive T-Lymphocytes/pathology , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/pathology , CD8-Positive T-Lymphocytes/virology , COVID-19 , Convalescence , Coronavirus Infections/complications , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Dendritic Cells/pathology , Dendritic Cells/virology , Diabetes Complications , Diabetes Mellitus/diagnosis , Diabetes Mellitus/virology , Disease Progression , Female , Humans , Hypertension/complications , Hypertension/diagnosis , Hypertension/virology , Killer Cells, Natural/immunology , Killer Cells, Natural/pathology , Killer Cells, Natural/virology , Lymphocyte Activation , Lymphocyte Count , Male , Middle Aged , Monocytes/immunology , Monocytes/pathology , Monocytes/virology , Pandemics , Pneumonia, Viral/complications , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , SARS-CoV-2 , Severity of Illness Index
9.
Emerg Microbes Infect ; 9(1): 1664-1670, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-630769

ABSTRACT

Coronavirus disease 2019 (COVID-19) has a wide spectrum of disease severity from mild upper respiratory symptoms to respiratory failure. The role of neutralizing antibody (NAb) response in disease progression remains elusive. This study determined the seroprevalence of 733 non-COVID-19 individuals from April 2018 to February 2020 in the Hong Kong Special Administrative Region and compared the neutralizing antibody (NAb) responses of eight COVID-19 patients admitted to the intensive care unit (ICU) with those of 42 patients not admitted to the ICU. We found that NAb against SARS-CoV-2 was not detectable in any of the anonymous serum specimens from the 733 non-COVID-19 individuals. The peak serum geometric mean NAb titer was significantly higher among the eight ICU patients than the 42 non-ICU patients (7280 [95% confidence interval (CI) 1468-36099]) vs (671 [95% CI, 368-1223]). Furthermore, NAb titer increased significantly at earlier infection stages among ICU patients than among non-ICU patients. The median number of days to reach the peak Nab titers after symptoms onset was shorter among the ICU patients (17.6) than that of the non-ICU patients (20.1). Multivariate analysis showed that oxygen requirement and fever during admission were the only clinical factors independently associated with higher NAb titers. Our data suggested that SARS-CoV-2 was unlikely to have silently spread before the COVID-19 emergence in Hong Kong. ICU patients had an accelerated and augmented NAb response compared to non-ICU patients, which was associated with disease severity. Further studies are required to understand the relationship between high NAb response and disease severity.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , Adult , Aged , COVID-19 , Cells, Cultured , Female , Humans , Intensive Care Units , Male , Middle Aged , Pandemics , SARS-CoV-2
10.
J Med Virol ; 92(11): 2725-2734, 2020 11.
Article in English | MEDLINE | ID: covidwho-530466

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the coronavirus disease 2019 (COVID-19) pandemic. Accurate detection of SARS-CoV-2 using molecular assays is critical for patient management and the control of the COVID-19 pandemic. However, there is an increasing number of SARS-CoV-2 viruses with mutations at the primer or probe binding sites, and these mutations may affect the sensitivity of currently available real-time reverse transcription-polymerase chain reaction (RT-PCR) assays targeting the nucleocapsid (N), envelope (E), and open reading frame 1a or 1b genes. Using sequence-independent single-primer amplification and nanopore whole-genome sequencing, we have found that the nonstructural protein 1 (nsp1) gene, located at the 5' end of the SARS-CoV-2 genome, was highly expressed in the nasopharyngeal or saliva specimens of 9 COVID-19 patients of different clinical severity. Based on this finding, we have developed a novel nsp1 real-time RT-PCR assay. The primers and probes are highly specific for SARS-CoV-2. Validation with 101 clinical specimens showed that our nsp1 RT-PCR assay has a sensitivity of 93.1% (95% confidence interval [CI]: 86.2%-97.2%), which was similar to those of N and E gene RT-PCR assays. The diagnostic specificity was 100% (95% CI: 92.9%-100%). The addition of nsp1 for multitarget detection of SARS-CoV-2 can avoid false-negative results due to mutations at the primers/probes binding sites of currently available RT-PCR assays.


Subject(s)
COVID-19/diagnosis , Nanopore Sequencing/methods , RNA-Dependent RNA Polymerase/genetics , SARS-CoV-2/genetics , Viral Nonstructural Proteins/genetics , Whole Genome Sequencing/methods , COVID-19/virology , COVID-19 Nucleic Acid Testing , Female , Humans , Male , Middle Aged , Mutation , Nasopharynx/virology , Open Reading Frames , RNA, Viral/genetics , Saliva/virology , Sensitivity and Specificity
11.
Cell Rep ; 31(9): 107725, 2020 06 02.
Article in English | MEDLINE | ID: covidwho-276452

ABSTRACT

The World Health Organization has declared the ongoing outbreak of COVID-19, which is caused by a novel coronavirus SARS-CoV-2, a pandemic. There is currently a lack of knowledge about the antibody response elicited from SARS-CoV-2 infection. One major immunological question concerns antigenic differences between SARS-CoV-2 and SARS-CoV. We address this question by analyzing plasma from patients infected by SARS-CoV-2 or SARS-CoV and from infected or immunized mice. Our results show that, although cross-reactivity in antibody binding to the spike protein is common, cross-neutralization of the live viruses may be rare, indicating the presence of a non-neutralizing antibody response to conserved epitopes in the spike. Whether such low or non-neutralizing antibody response leads to antibody-dependent disease enhancement needs to be addressed in the future. Overall, this study not only addresses a fundamental question regarding antigenicity differences between SARS-CoV-2 and SARS-CoV but also has implications for immunogen design and vaccine development.


Subject(s)
Antibodies, Viral/immunology , Antigens, Viral/immunology , Betacoronavirus/immunology , SARS Virus/immunology , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Cross Reactions/immunology , Enzyme-Linked Immunosorbent Assay , Humans , Male , Mice , Mice, Inbred BALB C , Neutralization Tests , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Receptors, Virus/metabolism , SARS-CoV-2 , Severe Acute Respiratory Syndrome/immunology , Severe Acute Respiratory Syndrome/prevention & control , Sf9 Cells , Vero Cells , Viral Vaccines/immunology
13.
Lancet ; 395(10238): 1695-1704, 2020 05 30.
Article in English | MEDLINE | ID: covidwho-232479

ABSTRACT

BACKGROUND: Effective antiviral therapy is important for tackling the coronavirus disease 2019 (COVID-19) pandemic. We assessed the efficacy and safety of combined interferon beta-1b, lopinavir-ritonavir, and ribavirin for treating patients with COVID-19. METHODS: This was a multicentre, prospective, open-label, randomised, phase 2 trial in adults with COVID-19 who were admitted to six hospitals in Hong Kong. Patients were randomly assigned (2:1) to a 14-day combination of lopinavir 400 mg and ritonavir 100 mg every 12 h, ribavirin 400 mg every 12 h, and three doses of 8 million international units of interferon beta-1b on alternate days (combination group) or to 14 days of lopinavir 400 mg and ritonavir 100 mg every 12 h (control group). The primary endpoint was the time to providing a nasopharyngeal swab negative for severe acute respiratory syndrome coronavirus 2 RT-PCR, and was done in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT04276688. FINDINGS: Between Feb 10 and March 20, 2020, 127 patients were recruited; 86 were randomly assigned to the combination group and 41 were assigned to the control group. The median number of days from symptom onset to start of study treatment was 5 days (IQR 3-7). The combination group had a significantly shorter median time from start of study treatment to negative nasopharyngeal swab (7 days [IQR 5-11]) than the control group (12 days [8-15]; hazard ratio 4·37 [95% CI 1·86-10·24], p=0·0010). Adverse events included self-limited nausea and diarrhoea with no difference between the two groups. One patient in the control group discontinued lopinavir-ritonavir because of biochemical hepatitis. No patients died during the study. INTERPRETATION: Early triple antiviral therapy was safe and superior to lopinavir-ritonavir alone in alleviating symptoms and shortening the duration of viral shedding and hospital stay in patients with mild to moderate COVID-19. Future clinical study of a double antiviral therapy with interferon beta-1b as a backbone is warranted. FUNDING: The Shaw-Foundation, Richard and Carol Yu, May Tam Mak Mei Yin, and Sanming Project of Medicine.


Subject(s)
Coronavirus Infections/drug therapy , Interferon beta-1b/therapeutic use , Lopinavir/therapeutic use , Pneumonia, Viral/drug therapy , Ribavirin/therapeutic use , Ritonavir/therapeutic use , Adult , Betacoronavirus , COVID-19 , Drug Combinations , Drug Therapy, Combination , Female , Hong Kong , Hospitalization , Humans , Male , Middle Aged , Pandemics , SARS-CoV-2
14.
Euro Surveill ; 25(16)2020 04.
Article in English | MEDLINE | ID: covidwho-108708

ABSTRACT

BackgroundThe ongoing coronavirus disease (COVID-19) pandemic has major impacts on health systems, the economy and society. Assessing infection attack rates in the population is critical for estimating disease severity and herd immunity which is needed to calibrate public health interventions. We have previously shown that it is possible to achieve this in real time to impact public health decision making.AimOur objective was to develop and evaluate serological assays applicable in large-scale sero-epidemiological studies.MethodsWe developed an ELISA to detect IgG and IgM antibodies to the receptor-binding domain (RBD) of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated its sensitivity and specificity in combination with confirmatory microneutralisation (MN) and 90% plaque reduction neutralisation tests (PRNT90) in 51 sera from 24 patients with virologically confirmed COVID-19 and in age-stratified sera from 200 healthy controls.ResultsIgG and IgM RBD ELISA, MN and PRNT90 were reliably positive after 29 days from illness onset with no detectable cross-reactivity in age-stratified controls. We found that PRNT90 tests were more sensitive in detecting antibody than MN tests carried out with the conventional 100 tissue culture infectious dose challenge. Heparinised plasma appeared to reduce the infectivity of the virus challenge dose and may confound interpretation of neutralisation test.ConclusionUsing IgG ELISA based on the RBD of the spike protein to screen sera for SARS-CoV-2 antibody, followed by confirmation using PRNT90, is a valid approach for large-scale sero-epidemiology studies.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections , Enzyme-Linked Immunosorbent Assay , Pandemics , Pneumonia, Viral , Seroepidemiologic Studies , Serologic Tests/methods , Spike Glycoprotein, Coronavirus/immunology , Adolescent , Adult , Aged , Animals , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Chlorocebus aethiops , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Female , Humans , Male , Middle Aged , Neutralization Tests , Pneumonia, Viral/diagnosis , Real-Time Polymerase Chain Reaction , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/analysis , Vero Cells , Young Adult
15.
Critical care and resuscitation : journal of the Australasian Academy of Critical Care Medicine ; 2020.
Article | WHO COVID | ID: covidwho-34896

ABSTRACT

OBJECTIVE: To report the first eight cases of critically ill patients with coronavirus disease 2019 (COVID-19) in Hong Kong, describing the treatments and supportive care they received and their 28-day outcomes. DESIGN: Multicentre retrospective observational cohort study. SETTING: Three multidisciplinary intensive care units (ICUs) in Hong Kong. PARTICIPANTS: All adult critically ill patients with confirmed COVID-19 admitted to ICUs in Hong Kong between 22 January and 11 February 2020. MAIN OUTCOME MEASURE: 28-day mortality. RESULTS: Eight out of 49 patients with COVID-19 (16%) were admitted to Hong Kong ICUs during the study period. The median age was 64.5 years (range, 42–70) with a median admission Sequential Organ Failure Assessment (SOFA) score of 6 (IQR, 4–7). Six patients (75%) required mechanical ventilation, six patients (75%) required vasopressors and two (25%) required renal replacement therapy. None of the patients required prone ventilation, nitric oxide or extracorporeal membrane oxygenation. The median times to shock reversal and extubation were 9 and 11 days respectively. At 28 days, one patient (12%) had died and the remaining seven (88%) all survived to ICU discharge. Only one of the survivors (14%) still required oxygen at 28 days. CONCLUSION: Critically ill patients with COVID-19 often require a moderate duration of mechanical ventilation and vasopressor support. Most of these patients recover and survive to ICU discharge with supportive care using lung protective ventilation strategies, avoiding excess fluids, screening and treating bacterial co-infection, and timely intubation. Lower rather than upper respiratory tract viral burden correlates with clinical severity of illness.

16.
Lancet Infect Dis ; 20(5): 565-574, 2020 05.
Article in English | MEDLINE | ID: covidwho-14173

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) causes severe community and nosocomial outbreaks. Comprehensive data for serial respiratory viral load and serum antibody responses from patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not yet available. Nasopharyngeal and throat swabs are usually obtained for serial viral load monitoring of respiratory infections but gathering these specimens can cause discomfort for patients and put health-care workers at risk. We aimed to ascertain the serial respiratory viral load of SARS-CoV-2 in posterior oropharyngeal (deep throat) saliva samples from patients with COVID-19, and serum antibody responses. METHODS: We did a cohort study at two hospitals in Hong Kong. We included patients with laboratory-confirmed COVID-19. We obtained samples of blood, urine, posterior oropharyngeal saliva, and rectal swabs. Serial viral load was ascertained by reverse transcriptase quantitative PCR (RT-qPCR). Antibody levels against the SARS-CoV-2 internal nucleoprotein (NP) and surface spike protein receptor binding domain (RBD) were measured using EIA. Whole-genome sequencing was done to identify possible mutations arising during infection. FINDINGS: Between Jan 22, 2020, and Feb 12, 2020, 30 patients were screened for inclusion, of whom 23 were included (median age 62 years [range 37-75]). The median viral load in posterior oropharyngeal saliva or other respiratory specimens at presentation was 5·2 log10 copies per mL (IQR 4·1-7·0). Salivary viral load was highest during the first week after symptom onset and subsequently declined with time (slope -0·15, 95% CI -0·19 to -0·11; R2=0·71). In one patient, viral RNA was detected 25 days after symptom onset. Older age was correlated with higher viral load (Spearman's ρ=0·48, 95% CI 0·074-0·75; p=0·020). For 16 patients with serum samples available 14 days or longer after symptom onset, rates of seropositivity were 94% for anti-NP IgG (n=15), 88% for anti-NP IgM (n=14), 100% for anti-RBD IgG (n=16), and 94% for anti-RBD IgM (n=15). Anti-SARS-CoV-2-NP or anti-SARS-CoV-2-RBD IgG levels correlated with virus neutralisation titre (R2>0·9). No genome mutations were detected on serial samples. INTERPRETATION: Posterior oropharyngeal saliva samples are a non-invasive specimen more acceptable to patients and health-care workers. Unlike severe acute respiratory syndrome, patients with COVID-19 had the highest viral load near presentation, which could account for the fast-spreading nature of this epidemic. This finding emphasises the importance of stringent infection control and early use of potent antiviral agents, alone or in combination, for high-risk individuals. Serological assay can complement RT-qPCR for diagnosis. FUNDING: Richard and Carol Yu, May Tam Mak Mei Yin, The Shaw Foundation Hong Kong, Michael Tong, Marina Lee, Government Consultancy Service, and Sanming Project of Medicine.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Saliva/virology , Adult , Aged , Betacoronavirus/genetics , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/immunology , Coronavirus Infections/virology , Female , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , SARS-CoV-2 , Severity of Illness Index , Viral Load
17.
Clin Infect Dis ; 71(15): 841-843, 2020 07 28.
Article in English | MEDLINE | ID: covidwho-724

ABSTRACT

The 2019 novel coronavirus (2019-nCoV) was detected in the self-collected saliva of 91.7% (11/12) of patients. Serial saliva viral load monitoring generally showed a declining trend. Live virus was detected in saliva by viral culture. Saliva is a promising noninvasive specimen for diagnosis, monitoring, and infection control in patients with 2019-nCoV infection.


Subject(s)
Betacoronavirus/isolation & purification , Coronavirus Infections/diagnosis , Coronavirus Infections/virology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/virology , Saliva/virology , Adult , Aged , Animals , COVID-19 , Cell Line , Chlorocebus aethiops , Female , Hong Kong , Humans , Infection Control/methods , Male , Middle Aged , Pandemics , SARS-CoV-2 , Vero Cells , Viral Load/methods
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