Mpox vaccination for men who have sex with men and their differential risk of exposure and infection

Following the post-COVID-19 reopening of the society with enhanced traveling between countries, people at risk of mpox infection, notably men who have sex with men (MSM) and people living with HIV, are facing increasing threat of virus exposure. Mpox vaccination is an important public health strategy which is provided free in Hong Kong to people at higher risk of infection. Between October 2022 and January 2023, 326 and 184 MSM vaccinees from vaccination sites and HIV specialist clinics in Hong Kong, respectively, were recruited for assessing their infection risks. Apart from the urge to protect one's significant others (68%), 45% were worried about the stigmatizing mpox symptoms if infected. Compared with MSM vaccinees at vaccination site, a lower proportion of MSM vaccinees in HIV care were sexually active in the past 6 months (88% vs 97%), but a higher proportion had recent sexually transmitted infection diagnoses (19% vs 10%) and perceived considerable exposure risk in the following 6 months (40% vs 22%). There were no differences in the perceived effectiveness of mpox vaccination. If optimal supplies of mpox vaccines can be secured, a low threshold approach at vaccination site could enable MSM with different levels of behavioral risks to become protected.

Boosting of serum neutralizing activity against the Omicron variant among recovered COVID-19 patients by BNT162b2 and CoronaVac vaccines

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).

Probable Animal-to-Human Transmission of SARS-CoV-2 Delta Variant AY.127 Causing a Pet Shop-Related COVID-19 Outbreak in Hong Kong

Background

SARS-CoV-2 can infect human and other mammals, including hamsters. Syrian (Mesocricetus auratus) and dwarf (Phodopus sp.) hamsters are susceptible to SARS-CoV-2 infection in the laboratory setting. However, pet shop-related COVID-19 outbreaks have not been reported.

Methods

We conducted an investigation of a pet shop-related COVID-19 outbreak due to Delta variant AY.127 involving at least three patients in Hong Kong. We tested samples collected from the patients, environment, and hamsters linked to this outbreak and performed whole genome sequencing analysis of the RT-PCR-positive samples.

Results

The patients included a pet shop keeper (Patient 1), a female customer of the pet shop (Patient 2), and the husband of Patient 2 (Patient 3). Investigation showed that 17.2% (5/29) and 25.5% (13/51) environmental specimens collected from the pet shop and its related warehouse, respectively, tested positive for SARS-CoV-2 RNA by RT-PCR. Among euthanized hamsters randomly collected from the storehouse, 3% (3/100) tested positive for SARS-CoV-2 RNA by RT-PCR and seropositive for anti-SARS-CoV-2 antibody by ELISA. Whole genome analysis showed that although all genomes from the outbreak belonged to the Delta variant AY.127, there were at least 3 nucleotide differences among the genomes from different patients and the hamster cages. Genomic analysis suggests that multiple strains have emerged within the hamster population, and these different strains have likely transmitted to human either via direct contact or via the environment.

Conclusions

Our study demonstrated probable hamster-to-human transmission of SARS-CoV-2. As pet trading is common around the world, this can represent a route of international spread of this pandemic virus.

Mitochondrial Dysfunction Associates With Acute T Lymphocytopenia and Impaired Functionality in COVID-19 Patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in rapid T lymphocytopenia and functional impairment of T cells. The underlying mechanism, however, remains incompletely understood. In this study, we focused on characterizing the phenotype and kinetics of T-cell subsets with mitochondrial dysfunction (MD) by multicolor flow cytometry and investigating the association between MD and T-cell functionality. While 73.9% of study subjects displayed clinical lymphocytopenia upon hospital admission, a significant reduction of CD4 or CD8 T-cell frequency was found in all asymptomatic, symptomatic, and convalescent cases. CD4 and CD8 T cells with increased MD were found in both asymptomatic and symptomatic patients within the first week of symptom onset. Lower proportion of memory CD8 T cell with MD was found in severe patients than in mild ones at the stage of disease progression. Critically, the frequency of T cells with MD in symptomatic patients was preferentially associated with CD4 T-cell loss and CD8 T-cell hyperactivation, respectively. Patients bearing effector memory CD4 and CD8 T cells with the phenotype of high MD exhibited poorer T-cell responses upon either phorbol 12-myristate-13-acetate (PMA)/ionomycin or SARS-CoV-2 peptide stimulation than those with low MD. Our findings demonstrated an MD-associated mechanism underlying SARS-CoV-2-induced T lymphocytopenia and functional impairment during the acute phase of infection.

Case series of HIV SARS-CoV-2 co-infection in Chinese adults

Objectives

Little is known whether differences exist in virus shedding, immune and inflammatory response related to SARS-CoV-2 in people living with human immunodeficiency virus (PLWH). We assessed viral RNA and cytokine profiles of HIV and SARS-CoV-2 coinfection in Hong Kong.

Methods

PLWH hospitalized with SARS-CoV-2 infection in Hong Kong were included, compared with age-matched and disease severity-matched SARS-CoV-2 infected controls (ratio of 1:5) from February 1st 2020 to July 31st 2020. SARS-CoV-2 infection was confirmed by public health laboratory and virus concentration was quantified by an in-house real-time reverse transcription-quantitative polymerase chain reaction. A panel of cytokines and chemokines were performed.

Results

HIV patients had a similar respiratory shedding profile compared to controls. Duration of faecal shedding of patient A, B, C and D were at least 9, 10, 33, and 11 days, respectively. HIV patients had lower plasma levels of IL-10 and NT-pro-BNP. All 4 PLWH cases showed seroconversion to SARS-CoV-2 with anti-SARS-CoV-2 S antibodies detected in serum collected between day 18 and 30 after symptom onset.

Conclusions

PLWH behaves similarly with HIV-negative controls in respiratory viral load, but with decrease in IL-10 and NT-proBNP. PLWH may have a lower risk of immunostimulatory effect due to lower IL-10.

Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant by Sera From BNT162b2 or CoronaVac Vaccine Recipients

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variant, designated as a variant of concern by the World Health Organization, carries numerous spike mutations that are known to evade neutralizing antibodies elicited by coronavirus disease 2019 (COVID-19) vaccines. A deeper understanding of the susceptibility of omicron variant to vaccine-induced neutralizing antibodies is urgently needed for risk assessment.

METHODS

Omicron variant strains HKU691 and HKU344-R346K were isolated from patients using TMPRSS2-overexpressing VeroE6 cells. Whole genome sequence was determined using nanopore sequencing. Neutralization susceptibility of ancestral lineage A virus and the omicron, delta and beta variants to sera from 25 BNT162b2 and 25 CoronaVac vaccine recipients was determined using a live virus microneutralization assay.

RESULTS

The omicron variant strain HKU344-R346K has an additional spike R346K mutation, which is present in 8.5% of strains deposited in the GISAID database. Only 20% and 24% of BNT162b2 recipients had detectable neutralizing antibody against the omicron variant HKU691 and HKU344-R346K, respectively, whereas none of the CoronaVac recipients had detectable neutralizing antibody titer against either omicron isolate. For BNT162b2 recipients, the geometric mean neutralization antibody titers (GMTs) of the omicron variant isolates (5.43 and 6.42) were 35.7-39.9-fold lower than that of the ancestral virus (229.4), and the GMTs of both omicron variant isolates were significantly lower than those of the beta and delta variants. There was no significant difference in the GMTs between HKU691 and HKU344-R346K.

CONCLUSIONS

Omicron variant escapes neutralizing antibodies elicited by BNT162b2 or CoronaVac. The additional R346K mutation did not affect the neutralization susceptibility. Our data suggest that the omicron variant may be associated with lower COVID-19 vaccine effectiveness.

Hepatitis E virus species C infection in humans, Hong Kong

BACKGROUND

Hepatitis E virus (HEV) variants belonging to Orthohepevirus species A (HEV-A) are the primary cause of human hepatitis E. However, we previously reported that Orthohepevirus C (HEV-C1), a divergent HEV variant commonly found in rats, also causes hepatitis in humans. Here, we present a clinical-epidemiological investigation of human HEV-C1 infections detected in Hong Kong, with an emphasis on outcomes in immunocompromised individuals..

METHODS

A surveillance system for detecting human HEV-C1 infections was established in Hong Kong. Epidemiological and clinical characteristics of HEV-C1 cases identified via this system between August 1, 2019 and December 31, 2020 were retrieved. Phylogenetic analysis of HEV-C1 strain sequences was performed. Infection outcomes of immunocompromised individuals with HEV-A and HEV-C1 infections were analyzed.

RESULTS

HEV-C1 accounted for 8/53 (15.1%) RT-PCR confirmed hepatitis E infections in Hong Kong during the study period, raising the total number of HEV-C1 infections detected in the city to 16. Two distinct HEV-C1 strain groups caused human infections. Patients were elderly and/or immunocompromised; half tested negative for HEV IgM. Cumulatively, HEV-C1 accounted for 9/21 (42.9%) cases of hepatitis E recorded in immunocompromised patients in Hong Kong. Immunocompromised HEV-C1 patients progressed to persistent hepatitis at similar rates (7/9; 77.8%) as HEV-A patients (10/12; 75%). HEV-C1 patients responded to oral ribavirin although response to first course was sometimes poor or delayed.

CONCLUSIONS

Dedicated RT-PCR-based surveillance detected human HEV-C1 cases that evade conventional hepatitis E diagnostic testing. Immunosuppressed HEV-C1-infected patients frequently progress to persistent HEV-C1 infection for which ribavirin is a suitable treatment option.

Unique Clusters of Severe Acute Respiratory Syndrome Coronavirus 2 Causing a Large Coronavirus Disease 2019 Outbreak in Hong Kong

After two months of relative quiescence, a large COVID-19 outbreak occurred in Hong Kong in July 2020 after gradual relaxation of social distancing policy. Two unique SARS-CoV-2 phylogenetic clusters have been identified among locally-acquired cases, with most genomes belonging to cluster HK1 which is phylogenetically related to SARS-CoV-2 reported overseas.

MO386MASS SCREENING AND THE LOW RATES OF ACUTE KIDNEY INJURY AMONG COVID-19 PATIENTS IN HONG KONG

Background and Aims

Renal involvement in COVID-19 under vigilant public health surveillance, including mass screening and early hospitalization is less well-characterized. We assessed renal involvement of COVID-19 patients in Hong Kong, including the association with risk factors, length of hospitalization, critical presentation and mortality.

Method

Linked electronic records of all confirmed patients from 5 major designated hospitals were extracted. Primary outcome was the incidence of in-hospital AKI. Secondary outcomes were AKI-associated mortality, incident RRT, intensive care admission, prolonged hospitalization and disease course (defined as >90th percentile of hospitalization duration and duration from symptom onset to discharge, respectively), and change of eGFR. Patients were further stratified into being symptomatic or asymptomatic.

Results

Patients were characterized by young age (median:38.4, IQR:28.4-55.8 years old) and short time (Median:5, IQR:2-9 days) from symptom onset to admission. Among the 591 patients, 22 (3.72%) developed AKI and 4 (0.68%) required RRT. AKI increased the odds of prolonged hospitalization and disease course by 2.0 and 3.5 folds, respectively. Estimated GFR 24 weeks post-discharge reduced by 7.51 and 1.06 ml/min/1.73m² versus baseline (at admission) in the AKI and non-AKI groups, respectively. The incidence of AKI was comparable between asymptomatic (4.8%) and symptomatic (3.7%) patients.

Conclusion

The overall rate of AKI among COVID-19 patients in Hong Kong is low, which could be attributable to a vigilant screening program and early hospitalization. Among patients who developed in-hospital AKI, the duration of hospitalization is prolonged and kidney function impairment can persist for up to 6 months post-discharge. Mass surveillance for COVID-19 is warranted in identifying asymptomatic subjects for earlier AKI management.

Dynamics of B cell repertoires and emergence of cross-reactive responses in patients with different severities of COVID-19

Individuals with the 2019 coronavirus disease (COVID-19) show varying severity of the disease, ranging from asymptomatic to requiring intensive care. Although monoclonal antibodies specific to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been identified, we still lack an understanding of the overall landscape of B cell receptor (BCR) repertoires in individuals with COVID-19. We use high-throughput sequencing of bulk and plasma B cells collected at multiple time points during infection to characterize signatures of the B cell response to SARS-CoV-2 in 19 individuals. Using principled statistical approaches, we associate differential features of BCRs with different disease severity. We identify 38 significantly expanded clonal lineages shared among individuals as candidates for responses specific to SARS-CoV-2. Using single-cell sequencing, we verify the reactivity of BCRs shared among individuals to SARS-CoV-2 epitopes. Moreover, we identify the natural emergence of a BCR with cross-reactivity to SARS-CoV-1 and SARS-CoV-2 in some individuals. Our results provide insights important for development of rational therapies and vaccines against COVID-19.

Dynamics of B-cell repertoires and emergence of cross-reactive responses in COVID-19 patients with different disease severity

COVID-19 patients show varying severity of the disease ranging from asymptomatic to requiring intensive care. Although a number of SARS-CoV-2 specific monoclonal antibodies have been identified, we still lack an understanding of the overall landscape of B-cell receptor (BCR) repertoires in COVID-19 patients. Here, we used high-throughput sequencing of bulk and plasma B-cells collected over multiple time points during infection to characterize signatures of B-cell response to SARS-CoV-2 in 19 patients. Using principled statistical approaches, we determined differential features of BCRs associated with different disease severity. We identified 38 significantly expanded clonal lineages shared among patients as candidates for specific responses to SARS-CoV-2. Using single-cell sequencing, we verified reactivity of BCRs shared among individuals to SARS-CoV-2 epitopes. Moreover, we identified natural emergence of a BCR with cross-reactivity to SARS-CoV-1 and SARS-CoV-2 in a number of patients. Our results provide important insights for development of rational therapies and vaccines against COVID-19.

Dynamics of B-cell repertoires and emergence of cross-reactive responses in COVID-19 patients with different disease severity

COVID-19 patients show varying severity of the disease ranging from asymptomatic to requiring intensive care. Although a number of SARS-CoV-2 specific monoclonal antibodies have been identified, we still lack an understanding of the overall landscape of B-cell receptor (BCR) repertoires in COVID-19 patients. Here, we used high-throughput sequencing of bulk and plasma B-cells collected over multiple time points during infection to characterize signatures of B-cell response to SARS-CoV-2 in 19 patients. Using principled statistical approaches, we determined differential features of BCRs associated with different disease severity. We identified 38 significantly expanded clonal lineages shared among patients as candidates for specific responses to SARS-CoV-2. Using single-cell sequencing, we verified reactivity of BCRs shared among individuals to SARS-CoV-2 epitopes. Moreover, we identified natural emergence of a BCR with cross-reactivity to SARS-CoV-1 and SARS-CoV-2 in a number of patients. Our results provide important insights for development of rational therapies and vaccines against COVID-19.

Mass Screening Is Associated with Low Rates of Acute Kidney Injury among COVID-19 Patients in Hong Kong

INTRODUCTION

Renal involvement in COVID-19 is less well characterized in settings with vigilant public health surveillance, including mass screening and early hospitalization. We assessed kidney complications among COVID-19 patients in Hong Kong, including the association with risk factors, length of hospitalization, critical presentation, and mortality.

METHODS

Linked electronic records of all patients with confirmed COVID-19 from 5 major designated hospitals were extracted. Duplicated records due to interhospital transferal were removed. Primary outcome was the incidence of in-hospital acute kidney injury (AKI). Secondary outcomes were AKI-associated mortality, incident renal replacement therapy (RRT), intensive care admission, prolonged hospitalization and disease course (defined as >90th percentile of hospitalization duration [35 days] and duration from symptom onset to discharge [43 days], respectively), and change of estimated glomerular filtration rate (GFR). Patients were further stratified into being symptomatic or asymptomatic.

RESULTS

Patients were characterized by young age (median: 38.4, IQR: 28.4-55.8 years) and short time (median: 5, IQR: 2-9 days) from symptom onset to admission. Among the 591 patients, 22 (3.72%) developed AKI and 4 (0.68%) required RRT. The median time from symptom onset to in-hospital AKI was 15 days. AKI increased the odds of prolonged hospitalization and disease course by 2.0- and 3.5-folds, respectively. Estimated GFR 24 weeks post-discharge reduced by 7.51 and 1.06 mL/min/1.73 m2 versus baseline (upon admission) in the AKI and non-AKI groups, respectively. The incidence of AKI was comparable between asymptomatic (4.8%, n = 3/62) and symptomatic (3.7%, n = 19/519) patients.

CONCLUSION

The overall rate of AKI among COVID-19 patients in Hong Kong is low, which could be attributable to a vigilant screening program and early hospitalization. Among patients who developed in-hospital AKI, the duration of hospitalization is prolonged and kidney function impairment can persist for up to 6 months post-discharge. Mass surveillance for COVID-19 is warranted in identifying asymptomatic subjects for earlier AKI management.

Transmission of Rat Hepatitis E Virus Infection to Humans in Hong Kong: A Clinical and Epidemiological Analysis

BACKGROUND AND AIMS

Hepatitis E virus (HEV) variants causing human infection predominantly belong to HEV species A (HEV-A). HEV species C genotype 1 (HEV-C1) circulates in rats and is highly divergent from HEV-A. It was previously considered unable to infect humans, but the first case of human HEV-C1 infection was recently discovered in Hong Kong. The aim of this study is to further describe the features of this zoonosis in Hong Kong.

APPROACH AND RESULTS

We conducted a territory-wide prospective screening study for HEV-C1 infection over a 31-month period. Blood samples from 2,860 patients with abnormal liver function (n = 2,201) or immunosuppressive conditions (n = 659) were screened for HEV-C1 RNA. In addition, 186 captured commensal rats were screened for HEV-C1 RNA. Sequences of human-derived and rat-derived HEV-C1 isolates were compared. Epidemiological and clinical features of HEV-C1 infection were analyzed. HEV-C1 RNA was detected in 6/2,201 (0.27%) patients with hepatitis and 1/659 (0.15%) immunocompromised persons. Including the previously reported case, eight HEV-C1 infections were identified, including five in patients who were immunosuppressed. Three patients had acute hepatitis, four had persistent hepatitis, and one had subclinical infection without hepatitis. One patient died of meningoencephalitis, and HEV-C1 was detected in cerebrospinal fluid. HEV-C1 hepatitis was generally milder than HEV-A hepatitis. HEV-C1 RNA was detected in 7/186 (3.76%) rats. One HEV-C1 isolate obtained from a rat captured near the residences of patients was closely related to the major outbreak strain.

CONCLUSIONS

HEV-C1 is a cause of hepatitis E in humans in Hong Kong. Immunosuppressed individuals are susceptible to persistent HEV-C1 infection and extrahepatic manifestations. Subclinical HEV-C1 infection threatens blood safety. Tests for HEV-C1 are required in clinical laboratories.

561. Safety of Remdesivir vs Standard Care in Patients with Moderate Covid-19

Background

Remdesivir (RDV) has been shown to shorten recovery time and was well tolerated in patients with severe COVID-19. Here we report safety of RDV in patients with moderate COVID-19.

Methods

We conducted an open-label, phase 3 trial (NCT04252664) in hospitalized patients with confirmed SARS-CoV-2 infection, evidence of pulmonary infiltrates, and oxygen saturation >94% on room air. Patients were randomly assigned to receive RDV (5 or 10 days) or standard of care (SOC). RDV was dosed intravenously at 200 mg on day 1, 100 mg daily thereafter. Adverse events (AEs) and laboratory abnormalities were evaluated through the day 11 data cut; safety data through day 28 will be presented at the meeting.

Results

584 patients were randomized and treated (5d RDV: n=191; 10d RDV, n=193; SOC: n=200). Baseline characteristics were balanced among groups; median (range) age was 57y (12-95y), 39% were female and 19% Black, 39% had arterial hypertension, 15% hyperlipidemia, 11% asthma. Briefly, across both the 5d and 10d arms, RDV was well tolerated with a similar rate of Grade 3 or 4 AEs and fewer SAEs compared to SOC (Table). AEs more common with RDV vs SOC included nausea, headache, and hypokalemia. Overall, across the 3 arms, incidence of AEs leading to discontinuation and death were low and no clinically relevant changes in laboratory parameters were observed. In addition, median changes in renal and liver function tests from baseline were not statistically significant between the RDV 5d and RDV 10d groups compared to the SOC only group at d14 (Table 1).

Table 1.

Conclusion

RDV given for 5d or 10d was well tolerated in patients with moderate COVID-19. No clinically significant safety signals were observed with RDV vs SOC.

Disclosures

Gerard J. Criner, MD, Gilead Sciences Inc. (Scientific Research Study Investigator)Regeneron (Scientific Research Study Investigator) Gerard J. Criner, MD, NO DISCLOSURE DATA Mi Young Ahn, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Gregory Huhn, MD, Gilead Sciences Inc. (Grant/Research Support, Scientific Research Study Investigator)Janssen (Grant/Research Support)Proteus (Grant/Research Support)US National Institutes of Health (Grant/Research Support)Viiv Healthcare (Grant/Research Support) Aruna Subramanian, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Carlos Lumbreras, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Stefan Schmiedel, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Robert H. Hyland, MD, Gilead Sciences Inc. (Employee, Shareholder) Vithika Suri, PhD, Gilead Sciences Inc. (Employee, Shareholder) Huyen Cao, MD, Gilead Sciences Inc. (Employee, Shareholder) Hongyuan Wang, PhD, Gilead Sciences Inc. (Employee, Shareholder) Devi SenGupta, MD, Gilead Sciences Inc. (Employee, Shareholder) Anand Chokkalingam, PhD, Gilead Sciences (Employee) Anu Osinusi, MD, Gilead Sciences (Employee) Diana M. Brainard, MD, Gilead Sciences (Employee) Yao-Shen Chen, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Yao-Shen Chen, MD, NO DISCLOSURE DATA Huldrych Günthard, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) D Jose Sanz-Moreno, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Judith A. Aberg, MD, Theratechnology (Consultant) Emanuele Nicastri, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Owen Tak-Yin Tsang, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Owen Tak-Yin Tsang, MD, NO DISCLOSURE DATA

73. Geographical Disparities in Clinical Outcomes of Severe COVID-19 Patients Treated with Remdesivir

Background

Remdesivir (RDV), a RNA polymerase inhibitor with potent in vitro activity against SARS-CoV-2, is the only treatment with demonstrated efficacy in shortening the duration of COVID-19. Here we report regional differences in clinical outcomes of severe COVID-19 patients treated with RDV, as part of an open-label, randomized phase-3 trial establishing RDV treatment duration.

Methods

Hospitalized patients with oxygen saturation ≤94%, a positive SARS-CoV-2 PCR in the past 4 days and radiographic evidence of pneumonia were randomized 1:1 to receive 5d or 10d of intravenous RDV. We compared d14 clinical outcomes of patients from different geographical areas, as measured by mortality rates, change in clinical status from baseline (BL) on a 7-point ordinal scale and change in O2 requirements from BL. Based on previous analyses in compassionate use data showing region as an important predictor of outcome, Italy was examined separately from other regions.

Results

397 patients were treated with RDV, of which 229 (58%) were in the US, 77 (19%) Italy, 61 (15% in Spain), 12 (3%) Republic of Korea, 9 (2%) Singapore, 4 (1%) Germany, 4 (1%) Hong Kong and 1 (< 1%) Taiwan. BL clinical status was worse in Italy compared to other regions (72% vs 17% requiring high-flow oxygen delivery or higher), and Italian patients were more likely to be male than patients from other regions (69% vs 63%). Overall results showed 5d RDV was as effective as 10d. Mortality at d14 was higher in Italy (18%) compared to all other countries except Italy (7%). Similarly, clinical improvement at d14, measured as ≥2-point increase in the ordinal scale, was lower in Italian patients (39%) compared to all other countries combined (64%). (Fig.1).

Figure 1. Change from Baseline in Clinical Status (measured on a 7-point Ordinal Scale) at d14.

Conclusion

Overall, our results demonstrate significant geographical differences in the clinical course of severe COVID-19 patients treated with RDV. We observed worse outcomes, such as increased mortality and lower rate of clinical improvement, in patients from Italy compared to other regions.

Disclosures

George Diaz, MD, NO DISCLOSURE DATA Jose Ramon Arribas, MD, Alexa (Advisor or Review Panel member, Speaker’s Bureau, Other Financial or Material Support, Personal fees)Gilead Sciences Inc. (Scientific Research Study Investigator, Advisor or Review Panel member, Speaker’s Bureau, Other Financial or Material Support, Personal fees)Janssen (Advisor or Review Panel member, Speaker’s Bureau, Other Financial or Material Support, Personal fees)Merck (Advisor or Review Panel member, Speaker’s Bureau, Other Financial or Material Support, Personal fees)Viiv Healthcare (Advisor or Review Panel member, Speaker’s Bureau, Other Financial or Material Support, Personal fees) Jose Ramon Arribas, MD, NO DISCLOSURE DATA Philip A. Robinson, MD, NO DISCLOSURE DATA Anna Maria Cattelan, MD, NO DISCLOSURE DATA Karen T. Tashima, MD, Bristol-Myers Squibb (Research Grant or Support)Gilead Sciences Inc. (Grant/Research Support, Scientific Research Study Investigator)GlaxoSmithKline (Research Grant or Support)Merck (Research Grant or Support)Tibotec (Research Grant or Support)Viiv Healthcare (Research Grant or Support) Owen Tak-Yin Tsang, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Owen Tak-Yin Tsang, MD, NO DISCLOSURE DATA Yao-Shen Chen, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Yao-Shen Chen, MD, NO DISCLOSURE DATA Devi SenGupta, MD, Gilead Sciences Inc. (Employee, Shareholder) Elena Vendrame, MD, NO DISCLOSURE DATA Christiana Blair, MS, Gilead Sciences (Employee, Shareholder) Anand Chokkalingam, PhD, Gilead Sciences (Employee) Anu Osinusi, MD, Gilead Sciences (Employee) Diana M. Brainard, MD, Gilead Sciences (Employee) Bum Sik Chin, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) Bum Sik Chin, MD, NO DISCLOSURE DATA Christoph Spinner, MD, AbbVie (Advisor or Review Panel member, Other Financial or Material Support, Travel)Bristol-Myers Squibb (Grant/Research Support, Advisor or Review Panel member, Other Financial or Material Support, Travel)Gilead Sciences Inc. (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member, Other Financial or Material Support, Travel)Janssen (Grant/Research Support, Advisor or Review Panel member, Other Financial or Material Support, Travel)MSD (Grant/Research Support, Advisor or Review Panel member, Other Financial or Material Support, Travel)Viiv Healthcare (Grant/Research Support, Advisor or Review Panel member, Other Financial or Material Support, Travel) Gerard J. Criner, MD, Gilead Sciences Inc. (Scientific Research Study Investigator)Regeneron (Scientific Research Study Investigator) Gerard J. Criner, MD, NO DISCLOSURE DATA Jose Muñoz, MD, NO DISCLOSURE DATA David Chien Boon Lye, MD, Gilead Sciences Inc. (Scientific Research Study Investigator) David Chien Boon Lye, MD, NO DISCLOSURE DATA Robert L. Gottlieb, MD, Gilead Sciences Inc. (Scientific Research Study Investigator)

Systems biological assessment of immunity to mild versus severe COVID-19 infection in humans

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.

Consistent Detection of 2019 Novel Coronavirus in Saliva

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.

Development and Evaluation of Novel and Highly Sensitive Single-Tube Nested Real-Time RT-PCR Assays for SARS-CoV-2 Detection

Sensitive molecular assays are critical for coronavirus disease 2019 (COVID-19) diagnosis. Here, we designed and evaluated two single-tube nested (STN) real-time RT-PCR assays, targeting SARS-CoV-2 RdRp/Hel and N genes. Both STN assays had a low limit of detection and did not cross react with other human coronaviruses and respiratory viruses. Using 213 initial respiratory specimens from suspected COVID-19 patients, the sensitivity of both the STN COVID-19-RdRp/Hel and the STN COVID-19-N assays was 100% (99/99), while that of the comparator non-nested N assay was 95% (94/99). Among 108 follow-up specimens from confirmed COVID-19 patients who tested negative by the non-nested COVID-19-RdRp/Hel assay, 28 (25.9%) were positive for SARS-CoV-2 by the STN COVID-19-RdRp/Hel or the STN COVID-19-N assay. To evaluate the performance of our novel STN assays in pooled specimens, we created four sample pools, with each pool consisting of one low positive specimen and 49 negative specimens. While the non-nested COVID-19-RdRp/Hel assay was positive in only one of four sample pools (25%), both of the STN assays were positive in two of four samples pools (50%). In conclusion, the STN assays are highly sensitive and specific for SARS-CoV-2 detection. Their boosted sensitivity offers advantages in non-traditional COVID-19 testing algorithms such as saliva screening and pooled sample screening during massive screening.

Acute SARS-CoV-2 Infection Impairs Dendritic Cell and T Cell Responses

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.

High neutralizing antibody titer in intensive care unit patients with COVID-19

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.

Evaluation of the commercially available LightMix® Modular E-gene kit using clinical and proficiency testing specimens for SARS-CoV-2 detection

BACKGROUND

Rapid and sensitive diagnostic assays for SARS-CoV-2 detection are required for prompt patient management and infection control. The analytical and clinical performances of LightMix® Modular SARS and Wuhan CoV E-gene kit, a widely used commercial assay for SARS-CoV-2 detection, have not been well studied.

OBJECTIVE

To evaluate the performance characteristics of the LightMix® E-gene kit in comparison with well-validated in-house developed COVID-19 RT-PCR assays.

STUDY DESIGN

Serial dilutions of SARS-CoV-2 culture isolate extracts were used for analytical sensitivity evaluation. A total of 289 clinical specimens from 186 patients with suspected COVID-19 and 8 proficiency testing (PT) samples were used to evaluate the diagnostic performance of the LightMix® E-gene kit against in-house developed COVID-19-RdRp/Hel and COVID-19-N RT-PCR assays.

RESULTS

The LightMix® E-gene kit had a limit of detection of 1.8 × 10-1 TCID50/mL, which was one log10 lower than those of the two in-house RT-PCR assays. The LightMix® E-gene kit (149/289 [51.6%]) had similar sensitivity as the in-house assays (144/289 [49.8%] for RdRp/Hel and 146/289 [50.5%] for N). All three assays gave correct results for all the PT samples. Cycle threshold (Cp) values of the LightMix® E-gene kit and in-house assays showed excellent correlation. Reproducibility of the Cp values was satisfactory with intra- and inter-assay coefficient of variation values <5%. Importantly, the LightMix® E-gene kit, when used as a stand-alone assay, was equally sensitive as testing algorithms using multiple COVID-19 RT-PCR assays.

CONCLUSIONS

The LightMix® E-gene kit is a rapid and sensitive assay for SARS-CoV-2 detection. It has fewer verification requirements compared to laboratory-developed tests.

Identification of nsp1 gene as the target of SARS-CoV-2 real-time RT-PCR using nanopore whole-genome sequencing

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.

Nanopore sequencing is useful in identifying highly expressed gene region for diagnostic tests.

nsp1 is a suitable alternative gene target for SARS‐CoV‐2 RT‐PCR.

Triple combination of interferon beta-1b, lopinavir-ritonavir, and ribavirin in the treatment of patients admitted to hospital with COVID-19: an open-label, randomised, phase 2 trial

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.

Cross-reactive Antibody Response between SARS-CoV-2 and SARS-CoV Infections

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.

Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study

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.

High incidence of hepatocellular carcinoma and cirrhotic complications in patients with psychiatric illness: a territory-wide cohort study

Background

Because of high-risk behaviours, sedentary lifestyle and side effects of medications, psychiatric patients are at risk of viral hepatitis, alcohol-related liver disease and non-alcoholic fatty liver disease. We aimed to study the incidence of hepatocellular carcinoma (HCC) and cirrhotic complications in psychiatric patients.

Methods

We identified consecutive adult patients in all public hospitals and clinics in Hong Kong with psychiatric diagnoses between year 2003 and 2007 using the Clinical Data Analysis and Reporting System, which represents in-patient and out-patient data of approximately 80% of the 7.4-million local population. The patients were followed for liver-related events (HCC and cirrhotic complications) and deaths until December 2017. Age- and sex-standardized incidence ratio (SIR) of HCC in psychiatric patients to the general population was estimated by Poisson model.

Results

We included 105,763 psychiatric patients without prior liver-related events in the final analysis. During a median (interquartile range) follow-up of 12.4 (11.0–13.7) years, 1461 (1.4%) patients developed liver-related events; 472 (0.4%) patients developed HCC. Compared with the general population, psychiatric patients had increased incidence of HCC (SIR 1.42, 95% confidence interval [CI] 1.28–1.57, P < 0.001). The SIR was highest in patients with drug-induced (SIR 3.18, 95% CI 2.41–4.11, P < 0.001) and alcohol-induced mental disorders (SIR 2.98, 95% CI 2.30–3.81, P < 0.001), but was also increased in patients with psychotic disorders (SIR 1.39, 95% CI 1.16–1.65, P < 0.001) and mood disorders (SIR 1.16, 95% CI 1.00–1.34, P = 0.047). Liver disease was the fifth most common cause of death in this population, accounting for 595 of 10,614 (5.6%) deaths. Importantly, 569 (38.9%) patients were not known to have liver diseases at the time of liver-related events. The median age at HCC diagnosis (61 [range 26–83] years) was older and the median overall survival (8.0 [95% CI 5.0–10.9] months) after HCC diagnosis was shorter in this cohort of psychiatric patients than other reports from Hong Kong.

Conclusions

HCC, cirrhotic complications, and liver-related deaths are common in psychiatric patients, but liver diseases are often undiagnosed. More efforts are needed to identify liver diseases in the psychiatric population so that treatments and screening for HCC and varices can be provided to patients in need.

Comparative tropism, replication kinetics, and cell damage profiling of SARS-CoV-2 and SARS-CoV with implications for clinical manifestations, transmissibility, and laboratory studies of COVID-19: an observational study

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported from China in January, 2020. SARS-CoV-2 is efficiently transmitted from person to person and, in 2 months, has caused more than 82 000 laboratory-confirmed cases of coronavirus disease 2019 (COVID-19) and 2800 deaths in 46 countries. The total number of cases and deaths has surpassed that of the 2003 severe acute respiratory syndrome coronavirus (SARS-CoV). Although both COVID-19 and severe acute respiratory syndrome (SARS) manifest as pneumonia, COVID-19 is associated with apparently more efficient transmission, fewer cases of diarrhoea, increased mental confusion, and a lower crude fatality rate. However, the underlying virus-host interactive characteristics conferring these observations on transmissibility and clinical manifestations of COVID-19 remain unknown.

Methods

We systematically investigated the cellular susceptibility, species tropism, replication kinetics, and cell damage of SARS-CoV-2 and compared findings with those for SARS-CoV. We compared SARS-CoV-2 and SARS-CoV replication in different cell lines with one-way ANOVA. For the area under the curve comparison between SARS-CoV-2 and SARS-CoV replication in Calu3 (pulmonary) and Caco2 (intestinal) cells, we used Student's t test. We analysed cell damage induced by SARS-CoV-2 and SARS-CoV with one-way ANOVA.

Findings

SARS-CoV-2 infected and replicated to comparable levels in human Caco2 cells and Calu3 cells over a period of 120 h (p=0·52). By contrast, SARS-CoV infected and replicated more efficiently in Caco2 cells than in Calu3 cells under the same multiplicity of infection (p=0·0098). SARS-CoV-2, but not SARS-CoV, replicated modestly in U251 (neuronal) cells (p=0·036). For animal species cell tropism, both SARS-CoV and SARS-CoV-2 replicated in non-human primate, cat, rabbit, and pig cells. SARS-CoV, but not SARS-CoV-2, infected and replicated in Rhinolophus sinicus bat kidney cells. SARS-CoV-2 consistently induced significantly delayed and milder levels of cell damage than did SARS-CoV in non-human primate cells (VeroE6, p=0·016; FRhK4, p=0·0004).

Interpretation

As far as we know, our study presents the first quantitative data for tropism, replication kinetics, and cell damage of SARS-CoV-2. These data provide novel insights into the lower incidence of diarrhoea, decreased disease severity, and reduced mortality in patients with COVID-19, with respect to the pathogenesis and high transmissibility of SARS-CoV-2 compared with SARS-CoV.

Funding

May Tam Mak Mei Yin, The Shaw Foundation Hong Kong, Richard Yu and Carol Yu, Michael Seak-Kan Tong, Respiratory Viral Research Foundation, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund, 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, Perfect Shape Medical, The Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for the Department of Health of the Hong Kong Special Administrative Region Government, The Theme-Based Research Scheme of the Research Grants Council, Sanming Project of Medicine in Shenzhen, and The High Level-Hospital Program, Health Commission of Guangdong Province, China.

Development of a Novel, Genome Subtraction-Derived, SARS-CoV-2-Specific COVID-19-nsp2 Real-Time RT-PCR Assay and Its Evaluation Using Clinical Specimens

The pandemic novel coronavirus infection, Coronavirus Disease 2019 (COVID-19), has affected at least 190 countries or territories, with 465,915 confirmed cases and 21,031 deaths. In a containment-based strategy, rapid, sensitive and specific testing is important in epidemiological control and clinical management. Using 96 SARS-CoV-2 and 104 non-SARS-CoV-2 coronavirus genomes and our in-house program, GolayMetaMiner, four specific regions longer than 50 nucleotides in the SARS-CoV-2 genome were identified. Primers were designed to target the longest and previously untargeted nsp2 region and optimized as a probe-free real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. The new COVID-19-nsp2 assay had a limit of detection (LOD) of 1.8 TCID50/mL and did not amplify other human-pathogenic coronaviruses and respiratory viruses. Assay reproducibility in terms of cycle threshold (Cp) values was satisfactory, with the total imprecision (% CV) values well below 5%. Evaluation of the new assay using 59 clinical specimens from 14 confirmed cases showed 100% concordance with our previously developed COVID-19-RdRp/Hel reference assay. A rapid, sensitive, SARS-CoV-2-specific real-time RT-PCR assay, COVID-19-nsp2, was developed.

Cross-reactive antibody response between SARS-CoV-2 and SARS-CoV infections

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

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Real-life efficacy and safety of paritaprevir/ritonavir, ombitasvir, and dasabuvir in chronic hepatitis C patients in Hong Kong

BACKGROUND AND AIM

In registration studies, combination therapy of paritaprevir/ritonavir, ombitasvir, and dasabuvir (PrOD) with and without ribavirin for 12-24 weeks can achieve > 90% sustained virological response (SVR) for genotype 1 hepatitis C virus (HCV) infection. However, data in Asia is scanty. We aimed to study the efficacy and safety of this combination therapy in chronic hepatitis C patients in Hong Kong.

METHODS

We retrospectively analyzed data from six local hospitals that have prescribed PrOD with and without ribavirin to patients with genotype 1 chronic HCV infection as part of a global compassionate program.

RESULTS

Among 41 patients treated, 35 (85%) patients had genotype 1b HCV infection, 6 (15%) had co-infection with human immunodeficiency virus, 35 (85%) failed previous peginterferon and ribavirin therapy, 25 (61%) had compensated liver cirrhosis, and 3 (7%) had liver transplantation. Thirty-five (85%) patients received 12-week treatment and six patients received 24-week treatment; 26 (63%) patients received ribavirin combination. Thirty-nine (95%; 95% confidence interval 88.5-100%) patients had undetectable HCV RNA at 12-week post-treatment, that is, SVR. The two patients who did not develop SVR discontinued treatment prematurely; both of them were treatment experienced with liver cirrhosis complicated by acute renal failure unrelated to the treatment of PrOD and ribavirin. No patient had hepatic decompensation.

CONCLUSIONS

Paritaprevir/ritonavir, ombitasvir, and dasabuvir with or without ribavirin is effective and safe in patients with genotype 1 HCV infection in real-life clinical setting in Hong Kong.

Comparison of acute hepatitis E infection outcome in patients with and without chronic hepatitis B infection: a 10 year retrospective study in three regional hospitals in Hong Kong

BACKGROUND

Acute hepatitis E virus (HEV) infection has recently become the commonest cause of acute viral hepatitis in Hong Kong (HK) with majority of HEV belonging to genotype 4. Studies from China have shown that acute hepatitis E patients with underlying chronic hepatitis B virus (HBV) infection may have a worse outcome than those without. In India where genotype 1 is more prevalent, superinfection with hepatitis E on patients with chronic liver disease including chronic hepatitis B infection can cause liver decompensation.

OBJECTIVES

The study aims to determine the clinical outcome of acute hepatitis E infection in patients with and without chronic hepatitis B infection in HK.

STUDY DESIGN

The rates of liver failure, liver-related mortality and all-cause mortality will be compared between acute hepatitis E patients with and without chronic hepatitis B. Analysis was performed using the Statistical Package for the Social Science (SPSS version 12.0). All statistical tests were two-sided, and statistical significance was taken as p<0.05.

RESULTS

Chronic HBV carriers with acute HEV infection were found to have higher liver failure rate, liver-related mortality and all-cause mortality, but the results did not reach statistical significance. Chronic HBV carriers were found to have statistically significantly lower admission ALT level, lower day 28 serum albumin level and higher day 28 serum ALT level.

CONCLUSIONS

A prospective study with sufficient sample size is needed to confirm whether the clinical outcome of patients with chronic HBV infection is worse compared with patients who were not chronic HBV carriers.

The Antimicrobal Stewardship Programme: where have we been...where are we going?

The misuse or overuse of antibiotics has been widely documented as one of the major causes of the emergence and transmission of multi-drug resistant organisms (MDRO). Antimicrobial resistance posed significant impacts to the increase in morbidity, mortality and cost of health care. In response to the threat of antibiotic resistance which has increased dramatically over the past ten years and the very few new antibiotics in the pipeline, Princess Margaret Hospital set up a Steering Committee with senior-level representatives from Infectious Disease, Microbiology and Pharmacy departments to devise an interventional programme called the Smart Use of Antibiotics Programme (SMAP) to offer guidance on the judicious use of antimicrobials. With concerted effort and support from hospital management and frontline clinicians, SMAP achieved significant monetary savings and a reduction in inappropriate antibiotic use. There was no adverse patient outcome in terms of mortality and morbidity

Clinical characteristics of nosocomial norovirus outbreaks in Hong Kong

Norovirus outbreaks occur worldwide every year and have become more frequent over the last few years. There were extensive outbreaks in Hong Kong from May to July 2006 and our aim was to describe nosocomial outbreaks from 1 May 2006 to 31 July 2006 in this retrospective observational study. A total of 38 confirmed norovirus outbreaks involving 218 patients were identified. Most of these patients were elderly with a mean age of 74.5 years (range: 3 months to 97 years); 62% of them were either totally or partially dependent for help with daily activities, 83.9% had underlying chronic medical problems and 56% had limited mobility. In all, 97.2% of individuals presented with diarrhoea and only 46.3% of them had vomiting. The median duration for diarrhoea was 3 days and the longest 24 days. The median duration of vomiting was one day and the longest 15 days. Fever occurred in one-third of all cases. Reverse transcriptase-polymerase chain reaction was positive for norovirus in 72.6% cases. We conclude that nosocomial norovirus infection often involves frail elderly patients with limited mobility and that these patients may have more prolonged symptoms.

Japanese encephalitis in Hong Kong

OBJECTIVES

To review past and present patterns of occurrence of Japanese encephalitis in Hong Kong and across Asia. A better understanding of the disease should facilitate the formulation of an effective strategic plan to prevent a future epidemic.

DATA SOURCES

Report of local cases, and literature search of MEDLINE up to November 2004.

STUDY SELECTION

Literature and data related to Japanese encephalitis.

DATA EXTRACTION

Relevant information and data were reviewed by the authors.

DATA SYNTHESIS

Since 16 July 2004, under the ordinance of Hong Kong, Japanese encephalitis has been a notifiable disease. In the past, Japanese encephalitis has reached epidemic proportions in Japan, South Korea, and some areas in China. It has spread globally and has a worldwide incidence of 35 000 to 50 000 cases per year with 10 000 deaths. Mortality is about 30% and survivors often suffer serious long-term morbidity. In 2004, there were five local cases of Japanese encephalitis in Hong Kong. Subsequent serological surveillance of serum samples from 1547 local inhabitants revealed that 37 were positive, ie 2.4% of local inhabitants had been exposed to the Japanese encephalitis virus in the past. Most local inhabitants are immunologically naive to Japanese encephalitis virus. Most infections in endemic areas are asymptomatic. Patients with symptomatic Japanese encephalitis usually present with fever, headache, and confusion. Other signs include neurosis, poliomyelitis, and convulsion. Investigations including magnetic resonance imaging, electroencephalography, and single photon emission computed tomography are not specific. A definitive diagnosis depends on serological studies. Treatment is mainly supportive.

CONCLUSIONS

The control of Japanese encephalitis in Hong Kong relies on an accurate surveillance system, vector control, vector avoidance, and vaccination of the at-risk population. At present, vaccination should be limited to travellers to endemic areas who would stay for longer than 1 month.

Severe acute respiratory syndrome-related diarrhea

BACKGROUND

Severe acute respiratory syndrome (SARS) is an emerging infectious disease and diarrhea has been reported in up to 76% of cases. The purpose of the present paper was to carry out a retrospective study of the clinical and demographic data of SARS patients with diarrhea in Princess Margaret Hospital.

METHODS

From 1 to 31 March 2003, hospital records from 240 patients with confirmed SARS were studied. Patients with watery stool of >/=3 times/day for at least 3 consecutive days were defined as the diarrhea group. Clinical and demographic data were compared between the diarrhea and non-diarrhea groups. Chest X-ray (CXR) scores during the peak of diarrhea period were recorded by a respiratory physician. These CXR scores were correlated with the peak frequency of diarrhea by Spearman's correlation coefficient.

RESULTS

Diarrhea occurred in 20.4% of patients after admission. Female patients were predominant with a female to male ratio of 6:1 (P < 0.001) and 69.4% of patients were living in Amoy Gardens Estate (P = 0.01). The proportions of patients requiring ventilatory care and mortality in the diarrhea group were 8.2% and 2%, respectively, which were significantly lower than those in the non-diarrhea group (27.6% and 16.2%, P < 0.005). The CXR scores during the peak of diarrhea were not correlated with the maximum frequency of diarrhea (r = -0.09, P = 0.5).

CONCLUSIONS

A total of 20.4% of SARS patients had the complication of diarrhea after hospital admission. Both female sex and being a resident of Amoy Gardens Estate were associated with diarrhea. The diarrhea group had a better prognosis.

Severe acute respiratory syndrome-related diarrhea

BACKGROUND

Severe acute respiratory syndrome (SARS) is an emerging infectious disease and diarrhea has been reported in up to 76% of cases. The purpose of the present paper was to carry out a retrospective study of the clinical and demographic data of SARS patients with diarrhea in Princess Margaret Hospital.

METHODS

From 1 to 31 March 2003, hospital records from 240 patients with confirmed SARS were studied. Patients with watery stool of >/=3 times/day for at least 3 consecutive days were defined as the diarrhea group. Clinical and demographic data were compared between the diarrhea and non-diarrhea groups. Chest X-ray (CXR) scores during the peak of diarrhea period were recorded by a respiratory physician. These CXR scores were correlated with the peak frequency of diarrhea by Spearman's correlation coefficient.

RESULTS

Diarrhea occurred in 20.4% of patients after admission. Female patients were predominant with a female to male ratio of 6:1 (P < 0.001) and 69.4% of patients were living in Amoy Gardens Estate (P = 0.01). The proportions of patients requiring ventilatory care and mortality in the diarrhea group were 8.2% and 2%, respectively, which were significantly lower than those in the non-diarrhea group (27.6% and 16.2%, P < 0.005). The CXR scores during the peak of diarrhea were not correlated with the maximum frequency of diarrhea (r = -0.09, P = 0.5).

CONCLUSIONS

A total of 20.4% of SARS patients had the complication of diarrhea after hospital admission. Both female sex and being a resident of Amoy Gardens Estate were associated with diarrhea. The diarrhea group had a better prognosis.

Coronavirus-positive nasopharyngeal aspirate as predictor for severe acute respiratory syndrome mortality

Severe acute respiratory syndrome (SARS) has caused a major epidemic worldwide. A novel coronavirus is deemed to be the causative agent. Early diagnosis can be made with reverse transcriptase-polymerase chain reaction (RT-PCR) of nasopharyngeal aspirate samples. We compared symptoms of 156 SARS-positive and 62 SARS-negative patients in Hong Kong; SARS was confirmed by RT-PCR. The RT-PCR-positive patients had significantly more shortness of breath, a lower lymphocyte count, and a lower lactate dehydrogenase level; they were also more likely to have bilateral and multifocal chest radiograph involvement, to be admitted to intensive care, to need mechanical ventilation, and to have higher mortality rates. By multivariate analysis, positive RT-PCR on nasopharyngeal aspirate samples was an independent predictor of death within 30 days.