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1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-337001

ABSTRACT

Objective In September 2020, records of 15,861 SARS-CoV-2 cases failed to upload from the Second Generation Laboratory Surveillance System (SGSS) to the Contact Tracing Advisory Service (CTAS) tool, resulting in a delay in the contact tracing of these cases. This study used CTAS data to determine the impact of this delay on health outcomes: transmission events, hospitalisations, and mortality. Previously, a modelling study had suggested a substantial impact. Design Observational study Setting England. Population Individuals testing positive for SARS-CoV-2 and their reported contacts. Main outcome measures Secondary attack rates (SARs), hospitalisations, and deaths amongst primary and secondary contacts were calculated, compared to all other concurrent, unaffected cases. SGSS records affected by the event were matched to CTAS records and successive contacts and cases were identified. Results The initiation of contact tracing was delayed by 3 days on average in the primary cases in the delay group (6 days) compared to the control group (3 days). This was associated with lower completion of contact tracing of primary cases in the delay group: 80% (95%CI: 79-81%) in the delay group and 83% (95%CI: 83-84%) in the control group. There was some evidence to suggest an increase in transmission to non-household contacts amongst those affected by the delay. The SAR for non-household contacts was higher amongst secondary contacts in the delay group than the control group (delay group: 7.9%, 95%CI:6.4% to 9.2%;control group: 5.9%, 95%CI: 5.3% to 6.6%). There was no evidence of a difference between the delay and control groups in the odds of hospitalisation (crude odds ratio: 1.1 (95%CI: 0.9 to 1.2) or death (crude odds ratio: 0.7 (0.1 to 4.0)) amongst secondary contacts. Conclusions The delay in contact tracing had a limited impact on population health outcomes. Strengths and limitations of the study Shows empirical data on the health impact of an event leading to a delay in contact tracing so can test hypotheses generated by models of the potential impact of a delay in contact tracing Estimates the extent of further transmission and odds of increased mortality or hospitalisation in up to the third generation of cases affected by the event The event acts as a natural experiment to describe the possible impact of contact tracing, comparing a group affected by chance by delayed contact tracing to a control group who experienced no delay Contact tracing was not completed for all individuals, so the study might not capture all affected contacts or transmissions

2.
Biomed Pharmacother ; 150: 112997, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1803595

ABSTRACT

BACKGROUND: This study aimed to investigate the seroreactivity of Coronavirus disease 2019 (COVID-19) vaccination and its adverse events among systemic lupus erythematosus (SLE) patients, rheumatoid arthritis (RA) patients, and healthy controls (HCs). METHODS: A total of 60 SLE patients, 70 RA patients and 35 HCs, who received a complete inactivated COVID-19 vaccine (Vero cells) regimen, were recruited in the current study. Serum IgG and IgM antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) were determined by using chemiluminescent microparticle immunoassay (CMIA). RESULTS: There were no significant differences regarding the seroprevalences of IgG and IgM antibodies against SARS-CoV-2, and the self-reported vaccination-related adverse events among SLE patients, RA patients and HCs. The inactivated COVID-19 vaccines appeared to be well-tolerated and moderately immunogenic. In addition, case-only analysis indicated that in SLE patients, the disease manifestation of rash and anti-SSA autoantibody were associated with seroprevalence of IgG antibody against SARS-CoV-2, whereas the uses of ciclosporin and leflunomide had influence on the seroprevalence of IgM antibody against SARS-CoV-2. In RA patients, rheumatoid factor (RF) appeared to be associated with the seroprevalence of IgG antibody against SARS-CoV-2. CONCLUSION: Our study reveals that the seroprevalences of IgG and IgM antibodies against SARS-CoV-2 and vaccination-related adverse effects are similar among SLE, RA and HCs, suggesting that COVID-19 vaccine is safe and effective for SLE and RA patients to prevent from the pandemic of COVID-19.


Subject(s)
Arthritis, Rheumatoid , COVID-19 , Lupus Erythematosus, Systemic , Animals , Antibodies, Viral , Arthritis, Rheumatoid/complications , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Chlorocebus aethiops , Humans , Immunoglobulin G , Immunoglobulin M , SARS-CoV-2 , Seroepidemiologic Studies , Vaccination , Vero Cells
3.
Nat Commun ; 13(1): 1012, 2022 02 23.
Article in English | MEDLINE | ID: covidwho-1709629

ABSTRACT

Mitigation of SARS-CoV-2 transmission from international travel is a priority. We evaluated the effectiveness of travellers being required to quarantine for 14-days on return to England in Summer 2020. We identified 4,207 travel-related SARS-CoV-2 cases and their contacts, and identified 827 associated SARS-CoV-2 genomes. Overall, quarantine was associated with a lower rate of contacts, and the impact of quarantine was greatest in the 16-20 age-group. 186 SARS-CoV-2 genomes were sufficiently unique to identify travel-related clusters. Fewer genomically-linked cases were observed for index cases who returned from countries with quarantine requirement compared to countries with no quarantine requirement. This difference was explained by fewer importation events per identified genome for these cases, as opposed to fewer onward contacts per case. Overall, our study demonstrates that a 14-day quarantine period reduces, but does not completely eliminate, the onward transmission of imported cases, mainly by dissuading travel to countries with a quarantine requirement.


Subject(s)
COVID-19/prevention & control , Communicable Diseases, Imported/prevention & control , Quarantine/legislation & jurisprudence , SARS-CoV-2/genetics , COVID-19/epidemiology , COVID-19/transmission , Communicable Diseases, Imported/epidemiology , Communicable Diseases, Imported/transmission , Contact Tracing , England/epidemiology , Genome, Viral/genetics , Genomics , Health Impact Assessment , Humans , SARS-CoV-2/classification , Travel/legislation & jurisprudence , Travel-Related Illness
4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-309055

ABSTRACT

Face recognition has become essential in our daily lives as a convenient and contactless method of accurate identity verification. Process such as identity verification at automatic border control gates or the secure login to electronic devices are increasingly dependant on such technologies. The recent COVID-19 pandemic have increased the value of hygienic and contactless identity verification. However, the pandemic led to the wide use of face masks, essential to keep the pandemic under control. The effect of wearing a mask on face recognition in a collaborative environment is currently sensitive yet understudied issue. We address that by presenting a specifically collected database containing three session, each with three different capture instructions, to simulate realistic use cases. We further study the effect of masked face probes on the behaviour of three top-performing face recognition systems, two academic solutions and one commercial off-the-shelf (COTS) system.

5.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-308159

ABSTRACT

Background: Identifying areas that pose the greatest risk for community transmission of COVID-19 is essential to direct public health action and allow safe re-opening of society. Spread of B.1.1.7 (alpha) lineage provided a unique opportunity to quantify COVID-19 transmission risk associated with community settings in England 2020/21. Methods: All cases of COVID-19 occurring between 11/2020 and 01/2021 reported through the English national contact tracing system included. Recruitment occurred when B.1.1.7 regional prevalence was between 20-80%. Case groups were defined as: >2 cases reporting the same, location and attendance date 7-3 days before onset. Genetic concordance, presence/absence of S-gene target failure (SGTF) in grouped cases, was determined. Odds ratios for concordance and 95% confidence intervals were calculated. Sensitivity analysis compared concordance in single to 2-3 day case groups. Findings: There were 41,325 case groups with SGTF data containing 115,410 exposure events. Odds ratios ranged from 1.87 (95% CI:1.76-1.98) for shops, 29.9 (95% CI:23.1-38.7), nursery/preschool and 35.6 (95% CI:19.7-64.2) for visiting friends/relatives. Odds ratios of concordance increased with larger cluster sizes in educational settings. Concordance estimates were reduced when case grouping time period was increased from 1 to 2-3 days. Interpretation: Transmission risk varies across community settings, likely due to different behavioural or environmental factors. Risk does not capture number of users which also affects impact of settings on transmission. Limited data for certain settings due to non-pharmaceutical interventions in place. We recommend data are used to guide policy and prioritise action when assessing and managing COVID-19 community case clusters. Funding: EB funded by EMBL. No additional funding.Declaration of Interest: None to declare

6.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327707

ABSTRACT

Background: The SARS-CoV-2 Omicron variant (B.1.1.529) has rapidly replaced the Delta variant (B.1.617.2) to become dominant in England. This epidemiological study assessed differences in transmissibility between the Omicron and Delta using two methods and data sources. Methods Omicron and Delta cases were identified through genomic sequencing, genotyping and S-gene target failure in England from 5-11 December 2021. Secondary attack rates for Omicron and Delta using named contacts and household clustering were calculated using national surveillance and contact tracing data. Logistic regression was used to control for factors associated with transmission. Findings Analysis of contact tracing data identified elevated secondary attack rates for Omicron vs Delta in household (15.0% vs 10.8%) and non-household (8.2% vs 3.7%) settings. The proportion of index cases resulting in residential clustering was twice as high for Omicron (16.1%) compared to Delta (7.3%). Transmission was significantly less likely from cases, or in named contacts, in receipt of three compared to two vaccine doses in household settings, but less pronounced for Omicron (aRR 0.78 and 0.88) compared to Delta (aRR 0.62 and 0.68). In non-household settings, a similar reduction was observed for Delta cases and contacts (aRR 0.84 and 0.51) but only for Omicron contacts (aRR 0.76, 95% CI: 0.58-0.93) and not cases in receipt of three vs two doses (aRR 0.95, 0.77-1.16). Interpretation Our study identified increased risk of onward transmission of Omicron, consistent with its successful global displacement of Delta. We identified a reduced effectiveness of vaccination in lowering risk of transmission, a likely contributor for the rapid propagation of Omicron.

7.
National Bureau of Economic Research Working Paper Series ; No. 27891, 2020.
Article in English | NBER, Grey literature | ID: grc-748331

ABSTRACT

We estimate the impact of mask mandates and other non-pharmaceutical interventions (NPI) on COVID-19 case growth in Canada, including regulations on businesses and gatherings, school closures, travel and self-isolation, and long-term care homes. We partially account for behavioral responses using Google mobility data. Our identification approach exploits variation in the timing of indoor face mask mandates staggered over two months in the 34 public health regions in Ontario, Canada's most populous province. We find that, in the first few weeks after implementation, mask mandates are associated with a reduction of 25 percent in the weekly number of new COVID-19 cases. Additional analysis with province-level data provides corroborating evidence. Counterfactual policy simulations suggest that mandating indoor masks nationwide in early July could have reduced the weekly number of new cases in Canada by 25 to 40 percent in mid-August, which translates into 700 to 1,100 fewer cases per week.

8.
International Journal of Infectious Diseases ; 94:68-71, 2020.
Article in English | CAB Abstracts | ID: covidwho-1409677

ABSTRACT

Objectives: To compare the clinical characteristics and the dynamics of viral load between imported and non-imported patients with COVID-19. Design and methods: Data from 51 laboratory-confirmed patients were retrospectively analyzed.

9.
Cell Res ; 31(8): 836-846, 2021 08.
Article in English | MEDLINE | ID: covidwho-1275907

ABSTRACT

Severe COVID-19 disease caused by SARS-CoV-2 is frequently accompanied by dysfunction of the lungs and extrapulmonary organs. However, the organotropism of SARS-CoV-2 and the port of virus entry for systemic dissemination remain largely unknown. We profiled 26 COVID-19 autopsy cases from four cohorts in Wuhan, China, and determined the systemic distribution of SARS-CoV-2. SARS-CoV-2 was detected in the lungs and multiple extrapulmonary organs of critically ill COVID-19 patients up to 67 days after symptom onset. Based on organotropism and pathological features of the patients, COVID-19 was divided into viral intrapulmonary and systemic subtypes. In patients with systemic viral distribution, SARS-CoV-2 was detected in monocytes, macrophages, and vascular endothelia at blood-air barrier, blood-testis barrier, and filtration barrier. Critically ill patients with long disease duration showed decreased pulmonary cell proliferation, reduced viral RNA, and marked fibrosis in the lungs. Permanent SARS-CoV-2 presence and tissue injuries in the lungs and extrapulmonary organs suggest direct viral invasion as a mechanism of pathogenicity in critically ill patients. SARS-CoV-2 may hijack monocytes, macrophages, and vascular endothelia at physiological barriers as the ports of entry for systemic dissemination. Our study thus delineates systemic pathological features of SARS-CoV-2 infection, which sheds light on the development of novel COVID-19 treatment.


Subject(s)
COVID-19/pathology , Lung/virology , SARS-CoV-2/isolation & purification , Aged , Aged, 80 and over , Autopsy , COVID-19/virology , China , Cohort Studies , Critical Illness , Female , Fibrosis , Hospitalization , Humans , Kidney/pathology , Kidney/virology , Leukocytes, Mononuclear/pathology , Leukocytes, Mononuclear/virology , Lung/pathology , Male , Middle Aged , RNA, Viral/metabolism , SARS-CoV-2/genetics , Spleen/pathology , Spleen/virology , Trachea/pathology , Trachea/virology
10.
J Health Econ ; 78: 102475, 2021 07.
Article in English | MEDLINE | ID: covidwho-1253199

ABSTRACT

We estimate the impact of indoor face mask mandates and other non-pharmaceutical interventions (NPI) on COVID-19 case growth in Canada. Mask mandate introduction was staggered from mid-June to mid-August 2020 in the 34 public health regions in Ontario, Canada's largest province by population. Using this variation, we find that mask mandates are associated with a 22 percent weekly reduction in new COVID-19 cases, relative to the trend in absence of mandate. Province-level data provide corroborating evidence. We control for mobility behaviour using Google geo-location data and for lagged case totals and case growth as information variables. Our analysis of additional survey data shows that mask mandates led to an increase of about 27 percentage points in self-reported mask wearing in public. Counterfactual policy simulations suggest that adopting a nationwide mask mandate in June could have reduced the total number of diagnosed COVID-19 cases in Canada by over 50,000 over the period July-November 2020. Jointly, our results indicate that mandating mask wearing in indoor public places can be a powerful policy tool to slow the spread of COVID-19.


Subject(s)
COVID-19 , Communicable Disease Control , Masks , Public Policy , COVID-19/prevention & control , Canada/epidemiology , Humans
11.
Canadian Journal of Microbiology ; 65(5):343-352, 2020.
Article in English | CAB Abstracts | ID: covidwho-889930

ABSTRACT

Porcine epidemic diarrhea virus (PEDV) causes severe infectious diseases in all ages of swine and leads to serious economic losses. Serologic tests are widely accepted and used to detect anti-PEDV antibodies that could indicate PEDV infection or vaccination. In this study, PEDV recombinant S1 protein (rS1) was expressed with the Bac-to-Bac system and purified by nickel-affinity chromatography. An indirect enzyme-linked immunosorbent assay based on rS1 (rS1-ELISA) was then developed and optimized by checkerboard assays with serial dilutions of antigen and serum. Serum samples from 453 domestic pigs and 42 vaccinated pigs were analyzed by the indirect fluorescent antibody (IFA) test and rS1-ELISA. Taking IFA as a gold standard, rS1-ELISA produced a high sensitivity (90.7%) and specificity (94.6%) by a receiver operating characteristic (ROC) curve. In addition, ROC analysis also revealed that rS1-ELISA was consistent with IFA (area under the curve 0.9583 +or- 0.0082). This rS1-ELISA was then applied to antibody detection in inactivated PEDV vaccinated pigs. The antibody could be detected 2-4 weeks after the first inoculation. These results indicated that the rS1-ELISA established in this study provides a promising and reliable tool for serologic detection of anti-PEDV IgG antibodies in infected or vaccinated pigs.

12.
Sci Adv ; 6(33): eabb7238, 2020 08.
Article in English | MEDLINE | ID: covidwho-733188

ABSTRACT

Cigarette smoking, the leading cause of chronic obstructive pulmonary disease (COPD), has been implicated as a risk factor for severe disease in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we show that mice with lung epithelial cell-specific loss of function of Miz1, which we identified as a negative regulator of nuclear factor κB (NF-κB) signaling, spontaneously develop progressive age-related changes resembling COPD. Furthermore, loss of Miz1 up-regulates the expression of Ace2, the receptor for SARS-CoV-2. Concomitant partial loss of NF-κB/RelA prevented the development of COPD-like phenotype in Miz1-deficient mice. Miz1 protein levels are reduced in the lungs from patients with COPD, and in the lungs of mice exposed to chronic cigarette smoke. Our data suggest that Miz1 down-regulation-induced sustained activation of NF-κB-dependent inflammation in the lung epithelium is sufficient to induce progressive lung and airway destruction that recapitulates features of COPD, with implications for COVID-19.


Subject(s)
Epithelial Cells/metabolism , Kruppel-Like Transcription Factors/metabolism , Lung/metabolism , Peptidyl-Dipeptidase A/metabolism , Phenotype , Protein Inhibitors of Activated STAT/genetics , Pulmonary Disease, Chronic Obstructive/genetics , Ubiquitin-Protein Ligases/genetics , Up-Regulation/genetics , Angiotensin-Converting Enzyme 2 , Animals , Betacoronavirus , COVID-19 , Coronavirus Infections/metabolism , Coronavirus Infections/virology , Gene Knockout Techniques , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Pandemics , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , Protein Inhibitors of Activated STAT/metabolism , Pulmonary Disease, Chronic Obstructive/etiology , Pulmonary Disease, Chronic Obstructive/metabolism , SARS-CoV-2 , Signal Transduction/genetics , Smoking/adverse effects , Transcription Factor RelA/metabolism , Ubiquitin-Protein Ligases/metabolism
13.
J Infect Public Health ; 13(9): 1363-1366, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-706757

ABSTRACT

An objective law was observed that naive case fatality rates (CFRs) of a disease will decrease early and then gradually increase infinitely near the true CFR as time went on during an outbreak. The normal growth of naive CFR was an inherent character rather than indicating the disease was becoming more severe. According to the law, by monitoring real-time naive CFRs, it can help outbreak-controllers know if there were many cases left unconfirmed or undiscovered in the outbreak. We reflected on the use of the naive CFR in the context of COVID-19 outbreaks. The results showed that Hubei Province of China, France and South Korea had cases that were not confirmed in a timely manner during the initial stages of the outbreak. Delayed case confirmations existed for long periods of time in France, Italy, the United Kingdom, the Netherlands and Spain. Monitoring of real-time naive CFRs could be helpful for decision-makers to identify under-reporting of cases during pandemics.


Subject(s)
Coronavirus Infections/mortality , Pandemics/statistics & numerical data , Pneumonia, Viral/mortality , Betacoronavirus , COVID-19 , China/epidemiology , Coronavirus Infections/diagnosis , Delayed Diagnosis , Europe/epidemiology , Humans , Pneumonia, Viral/diagnosis , Republic of Korea/epidemiology , SARS-CoV-2 , Time Factors
14.
Virol J ; 17(1): 80, 2020 06 19.
Article in English | MEDLINE | ID: covidwho-606695

ABSTRACT

BACKGROUND: Convalescent plasma (CP) transfusion was reported to be effective in treating critically ill patients with COVID-19, and hydroxychloroquine could potently inhibit SARS-CoV-2 in vitro. Herein, we reported a case receiving combination therapy with CP transfusion and hydroxychloroquine for the first time. CASE PRESENTATION: Laboratory findings showed high lactic acid level (2.1 mmol/L) and C-reactive protein (CRP, 48.8 mg/L), and low white blood cell count (1.96 × 109/L) in a 65-year-old Chinese man, who was diagnosed with severe COVID-19. CP was intravenously given twice, and hydroxychloroquine was orally administrated for a week (0.2 g, three times a day). The lactic acid and C-reactive protein levels remained high (2.1 mmol/L and 73.23 mg/L, respectively), while the arterial oxyhemoglobin saturation decreased to 86% with a low oxygenation index (OI, 76 mmHg) on day 4 after CP transfusion. His temperature returned to normal and the OI ascended above 300 on day 11. Moreover, the RNA test remained positive in throat swab, and computed tomography revealed severe pulmonary lesions on day 11 after admission. CONCLUSION: These findings suggested that the effectiveness of combination therapy with CP and hydroxychloroquine may be non-optimal, and specific therapy needs to be explored.


Subject(s)
Blood Component Transfusion/methods , Coronavirus Infections/therapy , Hydroxychloroquine/administration & dosage , Pneumonia, Viral/therapy , Administration, Oral , Aged , Antibodies, Neutralizing/administration & dosage , Antibodies, Viral/administration & dosage , Betacoronavirus/isolation & purification , C-Reactive Protein/metabolism , COVID-19 , Coronavirus Infections/blood , Coronavirus Infections/drug therapy , Coronavirus Infections/immunology , Coronavirus Infections/virology , Humans , Immunization, Passive/methods , Lactic Acid/blood , Leukocyte Count , Male , Oxyhemoglobins , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Viral Load
15.
J Infect ; 81(1): e21-e23, 2020 07.
Article in English | MEDLINE | ID: covidwho-45736

ABSTRACT

Lopinavir/ritonavir and arbidol have been previously used to treat acute respiratory syndrome- coronavirus 2 (SARS-CoV-2) replication in clinical practice; nevertheless, their effectiveness remains controversial. In this study, we evaluated the antiviral effects and safety of lopinavir/ritonavir and arbidol in patients with the 2019-nCoV disease (COVID-19). Fifty patients with laboratory-confirmed COVID-19 were divided into two groups: including lopinavir/ritonavir group (34 cases) and arbidol group (16 cases). Lopinavir/ritonavir group received 400 mg/100mg of Lopinavir/ritonavir, twice a day for a week, while the arbidol group was given 0.2 g arbidol, three times a day. Data from these patients were retrospectively analyzed. The cycle threshold values of open reading frame 1ab and nucleocapsid genes by RT-PCR assay were monitored during antiviral therapy. None of the patients developed severe pneumonia or ARDS. There was no difference in fever duration between the two groups (P=0.61). On day 14 after the admission, no viral load was detected in arbidol group, but the viral load was found in 15(44.1%) patients treated with lopinavir/ritonavir. Patients in the arbidol group had a shorter duration of positive RNA test compared to those in the lopinavir/ritonavir group (P<0.01). Moreover, no apparent side effects were found in both groups. In conclusion, our data indicate that arbidol monotherapy may be superior to lopinavir/ritonavir in treating COVID-19.


Subject(s)
Antiviral Agents/therapeutic use , Betacoronavirus , Coronavirus Infections/drug therapy , Indoles/therapeutic use , Lopinavir/therapeutic use , Pneumonia, Viral/drug therapy , Ritonavir/therapeutic use , Adult , Antiviral Agents/administration & dosage , COVID-19 , Coronavirus Infections/virology , Drug Combinations , Female , Humans , Indoles/administration & dosage , Indoles/adverse effects , Lopinavir/adverse effects , Male , Middle Aged , Pandemics , Pneumonia, Viral/virology , Retrospective Studies , Ritonavir/adverse effects , SARS-CoV-2 , Viral Load
16.
Int J Infect Dis ; 94: 68-71, 2020 May.
Article in English | MEDLINE | ID: covidwho-8529

ABSTRACT

OBJECTIVES: To compare the clinical characteristics and the dynamics of viral load between imported and non-imported patients with COVID-19. DESIGN AND METHODS: Data from 51 laboratory-confirmed patients were retrospectively analyzed. RESULTS: The incubation period in the tertiary group was longer than that in the imported and secondary groups (both p < 0.05). Fever was the most common symptom at the onset of illness (73.33%, 58.82%, and 68.42%, respectively), and half of the patients had a low-grade temperature (<38.0 °C) with a short duration of fever (<7 days). CT scans showed that most patients in the three groups had bilateral pneumonia (80.00%, 76.47%, and 73.68%, respectively). Ct values detected in the tertiary patients were similar to those for the imported and secondary groups at the time of admission (both p > 0.05). For the tertiary group, the viral load was undetectable in half of the patients (52.63%) on day 7, and in all patients on day 14. For one third of the patients in the imported and secondary groups, the viral load remained positive on day 14 after the admission. CONCLUSIONS: COVID-19 can present as pneumonia with a low onset of symptoms, and the infectivity of SARS-CoV2 may gradually decrease in tertiary patients.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/virology , Pneumonia, Viral/virology , Viral Load , Adult , Aged , COVID-19 , Coronavirus Infections/complications , Female , Fever/etiology , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/complications , Retrospective Studies , SARS-CoV-2 , Serologic Tests
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