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1.
CMAJ ; 192(49): E1747-E1756, 2020 Dec 07.
Article in French | MEDLINE | ID: covidwho-1791000

ABSTRACT

CONTEXTE: La demande sans précédent de respirateurs N95 durant la pandémie de maladie à coronavirus 2019 (COVID-19) a entraîné une pénurie mondiale. Nous avons validé un protocole de décontamination rapide et économique répondant aux normes réglementaires afin de permettre la réutilisation sûre de ce type de masque. MÉTHODES: Nous avons contaminé 4 modèles courants de respirateurs N95 avec le coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) et avons évalué l'inactivation virale après une désinfection de 60 minutes à 70 °C et à une humidité relative de 0 %. De même, nous avons étudié l'efficacité de la désinfection thermique, à une humidité relative allant de 0 % à 70 %, de masques contaminés à Escherichia coli. Enfin, nous avons examiné des masques soumis à de multiples cycles de désinfection thermique: nous avons évalué leur intégrité structurelle à l'aide d'un microscope à balayage, et leurs propriétés protectrices au moyen des normes du National Institute for Occupational Safety and Health des États-Unis relatives à la filtration particulaire, à la résistance respiratoire et à l'ajustement. RÉSULTATS: Une seule désinfection thermique a suffi pour que le SRAS-CoV-2 ne soit plus décelable sur les masques étudiés. En ce qui concerne les masques contaminés à E. coli, une culture de 24 heures a révélé que la bactérie n'était pratiquement plus décelable sur les masques désinfectés à 70 °C et à une humidité relative de 50 %, contrairement aux masques non désinfectés (densité optique à une longueur d'onde de 600 nm : 0,02 ± 0,02 contre 2,77 ± 0,09; p < 0,001), mais qu'elle persistait sur les masques traités à une humidité relative moindre. Les masques ayant subi 10 cycles de désinfection avaient toujours des fibres de diamètre semblable à celui des fibres des masques non traités, et ils répondaient encore aux normes d'ajustement, de filtration et de résistance respiratoire. INTERPRÉTATION: La désinfection thermique a réussi à décontaminer les respirateurs N95 sans compromettre leur intégrité structurelle ni modifier leurs propriétés. Elle pourrait se faire dans les hôpitaux et les établissements de soins de longue durée avec de l'équipement facilement accessible, ce qui réduirait la pénurie de N95.

2.
Emerg Infect Dis ; 28(6)2022 Apr 08.
Article in English | MEDLINE | ID: covidwho-1785300

ABSTRACT

We studied SARS-CoV-2 genomes from travelers arriving in Hong Kong during November 2021-February 2022. In addition to Omicron and Delta variants, we detected a BA.1/BA.2 recombinant with a breakpoint near the 5' end of the spike gene in 2 epidemiologically linked case-patients. Continued surveillance for SARS-CoV-2 recombinants is needed.

3.
Lancet ; 399(10329): 1070-1078, 2022 03 12.
Article in English | MEDLINE | ID: covidwho-1735071

ABSTRACT

BACKGROUND: Transmission of SARS-CoV-2 from humans to other mammals, including pet animals, has been reported. However, with the exception of farmed mink, there is no previous evidence that these infected animals can infect humans, resulting in sustained human-to-human transmission. Following a confirmed SARS-CoV-2 infection of a pet shop worker, animals in the shop and the warehouse supplying it were tested for evidence of SARS-CoV-2 infection. METHODS: In this case study, viral swabs and blood samples were collected from animals in a pet shop and its corresponding warehouse in Hong Kong. Nasal swab or saliva samples from human COVID-19 patients epidemiologically linked to the pet shop and from subsequent local cases confirmed to be infected by SARS-CoV-2 delta variant were collected. Oral swabs were tested by quantitative RT-PCR (RT-qPCR) for SARS-CoV-2 and blood samples were serologically tested by a surrogate virus neutralisation test and plaque reduction neutralisation test. The SARS-CoV-2 RT-qPCR positive samples were sequenced by next generation viral full genome sequencing using the ISeq sequencing platform (Illumina), and the viral genomes were phylogenetically analysed. FINDINGS: Eight (50%) of 16 individually tested Syrian hamsters in the pet shop and seven (58%) of 12 Syrian hamsters in the corresponding warehouse were positive for SARS-CoV-2 infection in RT-qPCR or serological tests. None of the dwarf hamsters (n=75), rabbits (n=246), guinea pigs (n=66), chinchillas (n=116), and mice (n=2) were confirmed positive for SARS-CoV-2 in RT-qPCR tests. SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to the delta variant of concern (AY.127) that had not been circulating locally before this outbreak. The viral genomes obtained from hamsters were phylogenetically related with some sequence heterogeneity. Phylogenetic dating suggests infection in these hamsters occurred around Oct 14, 2021 (95% CI Sept 15 to Nov 9, 2021). Multiple zoonotic transmission events to humans were detected, leading to onward human-to-human transmission. INTERPRETATION: Pet hamsters can be naturally infected with SARS-CoV-2. The virus can circulate among hamsters and lead to human infections. Both genetic and epidemiological results strongly suggest that there was more than one hamster-to-human transmission event in this study. This incident also led to onward human transmission. Importation of SARS-CoV-2-infected hamsters was a likely source of this outbreak. FUNDING: US National Institutes of Health, Research Grants Council of Hong Kong, Food and Health Bureau, and InnoHK.


Subject(s)
COVID-19/veterinary , Cricetinae/virology , SARS-CoV-2 , Viral Zoonoses/transmission , Adult , Animals , COVID-19/epidemiology , COVID-19/transmission , COVID-19 Nucleic Acid Testing , Child , Disease Outbreaks , Female , Hong Kong/epidemiology , Humans , Male , Pets/virology , Phylogeny
4.
Stem Cell Reports ; 17(3): 538-555, 2022 03 08.
Article in English | MEDLINE | ID: covidwho-1692861

ABSTRACT

To date, the direct causative mechanism of SARS-CoV-2-induced endotheliitis remains unclear. Here, we report that human ECs barely express surface ACE2, and ECs express less intracellular ACE2 than non-ECs of the lungs. We ectopically expressed ACE2 in hESC-ECs to model SARS-CoV-2 infection. ACE2-deficient ECs are resistant to the infection but are more activated than ACE2-expressing ones. The virus directly induces endothelial activation by increasing monocyte adhesion, NO production, and enhanced phosphorylation of p38 mitogen-associated protein kinase (MAPK), NF-κB, and eNOS in ACE2-expressing and -deficient ECs. ACE2-deficient ECs respond to SARS-CoV-2 through TLR4 as treatment with its antagonist inhibits p38 MAPK/NF-κB/ interleukin-1ß (IL-1ß) activation after viral exposure. Genome-wide, single-cell RNA-seq analyses further confirm activation of the TLR4/MAPK14/RELA/IL-1ß axis in circulating ECs of mild and severe COVID-19 patients. Circulating ECs could serve as biomarkers for indicating patients with endotheliitis. Together, our findings support a direct role for SARS-CoV-2 in mediating endothelial inflammation in an ACE2-dependent or -independent manner.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Models, Biological , SARS-CoV-2/physiology , Toll-Like Receptor 4/metabolism , Angiotensin-Converting Enzyme 2/genetics , COVID-19/pathology , COVID-19/virology , Endothelial Cells/cytology , Endothelial Cells/metabolism , Gene Expression Profiling , Human Umbilical Vein Endothelial Cells , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , NF-kappa B/antagonists & inhibitors , NF-kappa B/genetics , NF-kappa B/metabolism , Pluripotent Stem Cells/cytology , Pluripotent Stem Cells/metabolism , SARS-CoV-2/isolation & purification , Severity of Illness Index , Single-Cell Analysis , Toll-Like Receptor 4/antagonists & inhibitors , Toll-Like Receptor 4/genetics , p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolism
5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-321718

ABSTRACT

SARS-CoV-2 emerged in Wuhan in December 2019 and has caused the pandemic respiratory disease, COVID-19. Following what is presumed to be an initial zoonotic transmission event, the virus is now spreading efficient in humans. Very little is known about the susceptibility of domestic mammals kept as pets to this virus. Samples were collected over a 13-day period from a 17 year-old neutered male Pomeranian in Hong Kong SA that was taken into isolation after two members of the household tested positive for the virus. Nasal swabs were consistently positive on the five occasions the dog was tested using quantitative RT- PCR with viral loads between 7.5xE2 to 2.6 x10E4 RNA copies per mL of sample. The dog remained asymptomatic. Cultures attempted on three RT-PCR positive nasal samples were negative. Gene sequences from samples from two household members were identical. The viral sequence from the dog differed at three nucleotide positions;two of these resulted in amino acid changes but their significance is yet to be determined. Seroconversion was not detected but this was expected given the asymptomatic infection and low virus load. The evidence suggests that this is an instance of human-to-animal transmission of SARS-COV-2. It is likely that we could see similar events in other infected households. We do not have information yet on whether this virus can cause illness in dogs but no specific signs were seen in this dog. Whether infected dogs could transmit the virus to other animals or back to humans remains unknown. In this case it did not appear to have occurred.

6.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-321486

ABSTRACT

A pandemic caused by the novel SARS-CoV-2 virus with high nucleotide identity to SARS-CoV and SARS-related coronaviruses detected in horseshoe bats is spreading across the world and impacting the healthcare systems and global economy 1,2 . A suitable small animal model is urgently needed to support the development of vaccines and antiviral treatments against the SARS-CoV-2 virus. We report the pathogenesis and transmissibility of the SARS-CoV-2 in the golden Syrian hamster model. The SARS-CoV-2 virus replicated in the epithelial cells of respiratory and gastrointestinal tracts. Immunohistochemistry demonstrated viral antigens in the areas of lung consolidation on day 2 and 5 post- inoculation, followed by rapid viral clearance and tissue repairing on day 7. Viral antigen was also detected in the epithelial cells of duodenum without apparent inflammatory response on day 2. Notably, we observed that the SARS-CoV-2 virus can be transmitted efficiently from the inoculated hamsters to co-housed naïve contact hamsters. The inoculated hamsters and naturally-infected hamsters lost greater than 10% of the body weight, and all animals recovered with the detection of neutralizing antibodies within 14 days. Our results suggest that SARS-CoV-2 infection in golden Syrian hamsters resemble features found in human patients with mild infections.Authors Sin Fun Sia, Li-Meng Yan, and Alex WH Chin contributed equally to this work.

7.
SSRN;
Preprint in English | SSRN | ID: ppcovidwho-326533

ABSTRACT

Background: Transmission of SARS-CoV-2 from humans to other mammals, including pet animals, has been reported. However, with the exception of farmed mink, there is no previous documentation that these infected animals can infect humans, nor of further onward spread among humans. Following a confirmed SARS-CoV-2 infection of a pet store worker, animals in the store and the warehouse supplying it were tested for evidence of SARS-CoV-2 infection. Methods: Viral swabs and blood samples from pet animals were collected in a pet shop and the warehouse supplying it and tested by SARS-CoV-2 RT-PCR and serological assays, respectively. SARS-CoV-2 RT-PCR positive samples were studied by full genome sequencing analysis. Findings: Over 50% of individually tested Syrian hamsters in the pet shop (8/16) and warehouse (7/12) were positive for SARS-CoV-2 infection in RT-PCR or serological tests. None of dwarf hamsters (n=77), rabbits (n=246), Guinea pigs (n=66), chinchilla (n=116) and mice (n=2) were confirmed positive in RT-PCR tests. SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to Delta variant of concern (AY.127) that had not been circulating locally prior. These sequences are highly similar, but distinct. The viral genomes obtained from hamsters are phylogenetically related with some sequence heterogeneity and phylogenetic dating suggest infection in these hamsters occurred around 21 November 2021. Two separate transmission events to humans are documented, one leading to onward household spread. Interpretation: Pet hamsters can be naturally infected in “real-life” settings. The virus can circulate within hamsters and lead to human infections. Both genetic and epidemiological results strongly suggest that there were two independent hamster-to-human transmission and that such events can lead to onward human transmission. Importation of infected hamsters was the most likely source of virus infection.

8.
Nat Commun ; 13(1): 736, 2022 02 08.
Article in English | MEDLINE | ID: covidwho-1684024

ABSTRACT

Hong Kong employed a strategy of intermittent public health and social measures alongside increasingly stringent travel regulations to eliminate domestic SARS-CoV-2 transmission. By analyzing 1899 genome sequences (>18% of confirmed cases) from 23-January-2020 to 26-January-2021, we reveal the effects of fluctuating control measures on the evolution and epidemiology of SARS-CoV-2 lineages in Hong Kong. Despite numerous importations, only three introductions were responsible for 90% of locally-acquired cases. Community outbreaks were caused by novel introductions rather than a resurgence of circulating strains. Thus, local outbreak prevention requires strong border control and community surveillance, especially during periods of less stringent social restriction. Non-adherence to prolonged preventative measures may explain sustained local transmission observed during wave four in late 2020 and early 2021. We also found that, due to a tight transmission bottleneck, transmission of low-frequency single nucleotide variants between hosts is rare.


Subject(s)
COVID-19/epidemiology , SARS-CoV-2/genetics , COVID-19/transmission , COVID-19/virology , Genomics , Hong Kong/epidemiology , Humans , Public Health , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Travel
9.
ACS Appl Mater Interfaces ; 14(7): 8718-8727, 2022 Feb 23.
Article in English | MEDLINE | ID: covidwho-1683917

ABSTRACT

Transparent antimicrobial coatings can maintain the aesthetic appeal of surfaces and the functionality of a touch-screen while adding the benefit of reducing disease transmission. We fabricated an antimicrobial coating of silver oxide particles in a silicate matrix on glass. The matrix was grown by a modified Stöber sol-gel process with vapor-phase water and ammonia. A coating on glass with 2.4 mg of Ag2O per mm2 caused a reduction of 99.3% of SARS-CoV-2 and >99.5% of Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus compared to the uncoated glass after 1 h. We envisage that screen protectors with transparent antimicrobial coatings will find particular application to communal touch-screens, such as in supermarkets and other check-out or check-in facilities where a number of individuals utilize the same touch-screen in a short interval.


Subject(s)
Anti-Infective Agents/chemistry , Bacterial Infections/prevention & control , COVID-19/prevention & control , Oxides/chemistry , Silver Compounds/chemistry , Ammonia/chemistry , Anti-Infective Agents/pharmacology , Bacterial Infections/microbiology , COVID-19/virology , Glass/chemistry , Humans , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Oxides/pharmacology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/pathogenicity , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , Silicates/chemistry , Silver Compounds/pharmacology , Water/chemistry
10.
Sci Total Environ ; 824: 153687, 2022 Jun 10.
Article in English | MEDLINE | ID: covidwho-1665459

ABSTRACT

Wastewater surveillance is a promising tool for population-level monitoring of the spread of infectious diseases, such as the coronavirus disease 2019 (COVID-19). Different from clinical specimens, viruses in community-scale wastewater samples need to be concentrated before detection because viral RNA is highly diluted. The present study evaluated eleven different virus concentration methods for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater. First, eight concentration methods of different principles were compared using spiked wastewater at a starting volume of 30 mL. Ultracentrifugation was the most effective method with a viral recovery efficiency of 25 ± 6%. The second-best option, AlCl3 precipitation method, yielded a lower recovery efficiency, only approximately half that of the ultracentrifugation method. Second, the potential of increasing method sensitivity was explored using three concentration methods starting with a larger volume of 1000 mL. Although ultracentrifugation using a large volume outperformed the other two large-volume methods, it only yielded a comparable method sensitivity as the ultracentrifugation using a small volume (30 mL). Thus, ultracentrifugation using less volume of wastewater is more preferable considering the sample processing throughput. Third, a comparison of two viral RNA extraction methods showed that the lysis-buffer-based extraction method resulted in higher viral recovery efficiencies, with cycle threshold (Ct) values 0.9-4.2 lower than those obtained for the acid-guanidinium-phenol-based method using spiked samples. These results were further confirmed by using positive wastewater samples concentrated by ultracentrifugation and extracted separately by the two viral RNA extraction methods. In summary, concentration using ultracentrifugation followed by the lysis buffer-based extraction method enables sensitive and robust detection of SARS-CoV-2 for wastewater surveillance.


Subject(s)
COVID-19 , Viruses , Humans , RNA, Viral , SARS-CoV-2 , Viruses/genetics , Waste Water , Wastewater-Based Epidemiological Monitoring
11.
Nature ; 603(7902): 715-720, 2022 03.
Article in English | MEDLINE | ID: covidwho-1661972

ABSTRACT

The emergence of SARS-CoV-2 variants of concern with progressively increased transmissibility between humans is a threat to global public health. The Omicron variant of SARS-CoV-2 also evades immunity from natural infection or vaccines1, but it is unclear whether its exceptional transmissibility is due to immune evasion or intrinsic virological properties. Here we compared the replication competence and cellular tropism of the wild-type virus and the D614G, Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2) and Omicron (B.1.1.529) variants in ex vivo explant cultures of human bronchi and lungs. We also evaluated the dependence on TMPRSS2 and cathepsins for infection. We show that Omicron replicates faster than all other SARS-CoV-2 variants studied in the bronchi but less efficiently in the lung parenchyma. All variants of concern have similar cellular tropism compared to the wild type. Omicron is more dependent on cathepsins than the other variants of concern tested, suggesting that the Omicron variant enters cells through a different route compared with the other variants. The lower replication competence of Omicron in the human lungs may explain the reduced severity of Omicron that is now being reported in epidemiological studies, although determinants of severity are multifactorial. These findings provide important biological correlates to previous epidemiological observations.


Subject(s)
Bronchi/virology , Lung/virology , SARS-CoV-2/growth & development , Viral Tropism , Virus Replication , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Cathepsins/metabolism , Chlorocebus aethiops , Endocytosis , Humans , In Vitro Techniques , SARS-CoV-2/immunology , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Tissue Culture Techniques , Vero Cells
12.
Sci Total Environ ; 821: 153250, 2022 May 15.
Article in English | MEDLINE | ID: covidwho-1631648

ABSTRACT

Sewage surveillance could help develop proactive response to the Coronavirus Disease 2019 (COVID-19) pandemic, but currently there are limited reports about examples in practical exercises. Here, we report a use case of intensified sewage surveillance to initiate public health action to thwart a looming Delta variant outbreak in Hong Kong. On 21 June 2021, albeit under basically contained COVID-19 situation in Hong Kong, routine sewage surveillance identified a high viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a sewage sample from one site covering over 33,000 population, suggesting infected cases living in the respective sewershed. The use of a newly developed method based on allele-specific real-time quantitative polymerase chain reaction (AS RT-qPCR) served to alert the first documentation of the Delta variant in local community sewage three days before the case was confirmed to be a Delta variant carrier. Intensified sewage surveillance was triggered. Targeted upstream sampling at sub-sewershed areas pinpointed the source of positive viral signal across spatial scales from sewershed to building level, and assisted in determining the specific area for issuing a compulsory testing order for individuals on 23 June 2021. A person who lived in a building with the positive result of sewage testing was confirmed to be infected with COVID-19 on 24 June 2021. Viral genome sequences determined from the sewage sample were compared to those from the clinic specimens of the matched patient, and confirmed that the person was the source of the positive SARS-CoV-2 signal in the sewage sample. This study could help build confidences for public health agencies in using the sewage surveillance in their own communities.


Subject(s)
COVID-19 , COVID-19/epidemiology , Hong Kong/epidemiology , Humans , Public Health , SARS-CoV-2/genetics , Sewage
13.
Nat Med ; 28(3): 486-489, 2022 03.
Article in English | MEDLINE | ID: covidwho-1631094

ABSTRACT

The Omicron variant is rapidly becoming the dominant SARS-CoV-2 virus circulating globally. It is important to define reductions in virus neutralizing activity in the serum of convalescent or vaccinated individuals to understand potential loss of protection against infection by Omicron. We previously established that a 50% plaque reduction neutralization antibody titer (PRNT50) ≥25.6 in our live virus assay corresponded to the threshold for 50% protection from infection against wild-type (WT) SARS-CoV-2. Here we show markedly reduced serum antibody titers against the Omicron variant (geometric mean titer (GMT) < 10) compared to WT virus 3-5 weeks after two doses of BNT162b2 (GMT = 218.8) or CoronaVac vaccine (GMT = 32.5). A BNT162b2 booster dose elicited Omicron PRNT50 titers ≥25.6 in 88% of individuals (22 of 25) who previously received 2 doses of BNT162b2 and 80% of individuals (24 of 30) who previously received CoronaVac. However, few (3%) previously infected individuals (1 of 30) or those vaccinated with three doses of CoronaVac (1 of 30) met this threshold. Our findings suggest that countries primarily using CoronaVac vaccines should consider messenger RNA vaccine boosters in response to the spread of Omicron. Studies evaluating the effectiveness of different vaccines against the Omicron variant are urgently needed.


Subject(s)
Antibodies, Neutralizing , COVID-19 , Antibodies, Viral , COVID-19/prevention & control , Humans , SARS-CoV-2/genetics , Vaccination , Vaccines, Synthetic
14.
Emerg Infect Dis ; 28(1): 247-250, 2022 01.
Article in English | MEDLINE | ID: covidwho-1581409

ABSTRACT

We sequenced ≈50% of coronavirus disease cases imported to Hong Kong during March-July 2021 and identified 70 cases caused by Delta variants of severe acute respiratory syndrome coronavirus 2. The genomic diversity detected in Hong Kong was similar to global diversity, suggesting travel hubs can play a substantial role in surveillance.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19/epidemiology , Genomics , Hong Kong/epidemiology , Humans , Mass Screening , SARS-CoV-2/isolation & purification , Travel
15.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-293859

ABSTRACT

Background: A novel human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019, to cause a respiratory disease (COVID-19) of varying severity in Wuhan China, subsequently spreading to other parts of China and beyond. Methods: We infected ex vivo explant cultures of the human conjunctiva, bronchus and lung, and in vitro cultures of primary human alveolar epithelial cells and macrophages with SARS-CoV-2, and assessed viral tropism, replication competence and innate immune responses, in comparison with SARS-CoV, MERS-CoV, and the 2009 pandemic influenza H1N1 (pdmH1N1) virus.Findings: SARS-CoV-2 infected ciliated, mucus secreting and club cells of bronchial epithelium, spindled morphologically type I pneumocytes in the lung, and the conjunctival mucosa. Virus replication competence of SARS-CoV-2 in the bronchus was higher than that of SARS-CoV but lower than pdmH1N1. SARS-CoV-2 replication was comparable with SARS-CoV and pdmH1N1 in the lung but was lower than MERS-CoV. SARS-CoV-2 virus was a less potent inducer of pro-inflammatory cytokines compared with H5N1 and MERS-CoV. Influenza virus infection of alveolar epithelial cells increased ACE2 expression.Interpretation: The conjunctival epithelium and the conducting airways appear to be potential portals of infection of SARS-CoV-2. Both SARS-CoV and SARS-CoV-2 replicated comparably in the alveolar epithelium explaining the progression of infection to a primary viral pneumonia.Funding Statement: US National Institute of Allergy and Infectious Diseases (NIAID) under Centers of Excellence for Influenza Research and Surveillance (CEIRS) contract no. HHSN272201400006C and the Theme Based Research Scheme (Ref: T11-705/14N), Hong Kong Special Administrative Region.Declaration of Interests: There is no conflict of interest for all authors.Ethics Approval Statement: All experiments were carried out in a Bio-safety level 3 (BSL-3) facility. Informed consent was obtained from all subjects and approval was granted by the Institutional Review Board (IRB) of the University of Hong Kong and the Hospital Authority (Hong Kong West) (approval no: UW 20-167).

16.
Emerg Infect Dis ; 28(2): 460-462, 2022 02.
Article in English | MEDLINE | ID: covidwho-1551462

ABSTRACT

We report detection of severe acute respiratory syndrome coronavirus 2 Omicron variant (B.1.1.529) in an asymptomatic, fully vaccinated traveler in a quarantine hotel in Hong Kong, China. The Omicron variant was also detected in a fully vaccinated traveler staying in a room across the corridor from the index patient, suggesting transmission despite strict quarantine precautions.


Subject(s)
COVID-19 , SARS-CoV-2 , China/epidemiology , Hong Kong/epidemiology , Humans , Quarantine
17.
J Virol ; 96(3): e0197321, 2022 Feb 09.
Article in English | MEDLINE | ID: covidwho-1532966

ABSTRACT

Waning vaccine-induced immunity coupled with the emergence of SARS-CoV-2 variants has led to increases in breakthrough infections, prompting consideration for vaccine booster doses. Boosters have been reported to be safe and increase SARS-CoV-2-specific neutralizing antibody levels, but how these doses impact the trajectory of the global pandemic and herd immunity is unknown. Information on immunology, epidemiology, and equitable vaccine distribution should be considered when deciding the timing and eligibility for COVID-19 vaccine boosters.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/epidemiology , COVID-19/prevention & control , Health Services Needs and Demand/statistics & numerical data , Immunization, Secondary , SARS-CoV-2/immunology , Host-Pathogen Interactions/drug effects , Humans , Immunity, Herd , Outcome Assessment, Health Care , Vaccination
18.
Sci Rep ; 11(1): 22868, 2021 11 24.
Article in English | MEDLINE | ID: covidwho-1532097

ABSTRACT

Transfer of SARS-CoV-2 from solids to fingers is one step in infection via contaminated solids, and the possibility of infection from this route has driven calls for increased frequency of handwashing during the COVID-19 pandemic. To analyze this route of infection, we measured the percentage of SARS-CoV-2 that was transferred from a solid to an artificial finger. A droplet of SARS-CoV-2 suspension (1 µL) was placed on a solid, and then artificial skin was briefly pressed against the solid with a light force (3 N). Transfer from a variety of solids was detected, and transfer from the non-porous solids, glass, stainless steel, and Teflon, was substantial when the droplet was still wet. The viral titer for the finger was 13-16% or 0.8-0.9 log less than for the input droplet. Transfer still occurred after the droplet evaporated, but was smaller, 3-9%. We found a lower level of transfer from porous solids but did not find a significant effect of solid wettability for non-porous solids.


Subject(s)
COVID-19/transmission , Disease Transmission, Infectious/prevention & control , SARS-CoV-2/metabolism , COVID-19/metabolism , Equipment Contamination/prevention & control , Equipment Contamination/statistics & numerical data , Humans , SARS-CoV-2/pathogenicity , Skin/virology , Viral Load
19.
ACS Appl Mater Interfaces ; 13(46): 54706-54714, 2021 Nov 24.
Article in English | MEDLINE | ID: covidwho-1514382

ABSTRACT

Antimicrobial coatings are one method to reduce the spread of microbial diseases. Transparent coatings preserve the visual properties of surfaces and are strictly necessary for applications such as antimicrobial cell phone screens. This work describes transparent coatings that inactivate microbes within minutes. The coatings are based on a polydopamine (PDA) adhesive, which has the useful property that the monomer can be sprayed, and then the monomer polymerizes in a conformal film at room temperature. Two coatings are described (1) a coating where PDA is deposited first and then a thin layer of copper is grown on the PDA by electroless deposition (PDA/Cu) and (2) a coating where a suspension of Cu2O particles in a PDA solution is deposited in a single step (PDA/Cu2O). In the second coating, PDA menisci bind Cu2O particles to the solid surface. Both coatings are transparent and are highly efficient in inactivating microbes. PDA/Cu kills >99.99% of Pseudomonas aeruginosa and 99.18% of methicillin-resistant Staphylococcus aureus (MRSA) in only 10 min and inactivates 99.98% of SARS-CoV-2 virus in 1 h. PDA/Cu2O kills 99.94% of P. aeruginosa and 96.82% of MRSA within 10 min and inactivates 99.88% of SARS-CoV-2 in 1 h.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antiviral Agents/pharmacology , Drug Resistance, Microbial/drug effects , SARS-CoV-2/drug effects , COVID-19/virology , Humans , Methicillin-Resistant Staphylococcus aureus/drug effects , Pseudomonas aeruginosa/drug effects , Surface Properties
20.
Emerg Infect Dis ; 27(10): 2666-2668, 2021 10.
Article in English | MEDLINE | ID: covidwho-1486735

ABSTRACT

We sequenced 10% of imported severe acute respiratory syndrome coronavirus 2 infections detected in travelers to Hong Kong and revealed the genomic diversity of regions of origin, including lineages not previously reported from those countries. Our results suggest that international or regional travel hubs might be useful surveillance sites to monitor sequence diversity.


Subject(s)
COVID-19 , Communicable Diseases, Imported , Genetic Variation , Hong Kong/epidemiology , Humans , SARS-CoV-2
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