Distinctive COVID-19 manifestations and re-exposure to SARS CoV 2 in clinical laboratory personnel under regular monitoring by RT-PCR and serology

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Fábio de Oliveira Martinez Alonso ◽  
◽  
Bruno Duarte Sabino ◽  
Marianna Tavares Venceslau ◽  
Rafael Brandão Varella ◽  
...  
Keyword(s):  
Clinical Laboratory ◽  
Rt Pcr ◽  
Rna Detection ◽  
Laboratory Personnel ◽  
Regular Monitoring ◽  
Antibody Levels ◽  
Lack Of Knowledge

Clinical laboratory personnel (CLP) present a unique opportunity to investigate distinct forms of COVID-19 as they are under constant testing for SARS CoV 2 infection. SARS CoV 2 RNA and antibodies were routinely investigated over a 5-month period in 26 professionals from a clinical laboratory in RJ, Brazil. Of them, three (11.5%) CLP presented the following peculiar COVID-19 manifestations: 2/26 (7.7%) had SARS CoV 2 antibodies without RNA detection during the follow-up, with a possible re-exposure in one case, and 1/26 (3.8%) a confirmed reinfection with RNA detection, and possibly a third re-exposure. Based on a long follow-up of SARS CoV 2 infection in CLP, this study showed that cases of COVID-19 without RNA detection are not common, but it does indicate the risk of re-exposure after the fall of antibody levels. Although scarcely reported, the investigation of less frequent forms of COVID-19 is relevant, given the lack of knowledge of its impact on the pandemic.

scholarly journals Influenza Virus Detection Following Administration of Live-Attenuated Intranasal Influenza Vaccine in Children With Cystic Fibrosis and Their Healthy Siblings

2016 ◽  
Vol 3 (4) ◽  
Author(s):  
Constantina Boikos ◽  
Lawrence Joseph ◽  
Christine Martineau ◽  
Jesse Papenburg ◽  
David Scheifele ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Small Sample Size ◽  
Virus Detection ◽  
Credible Interval ◽  
Small Sample ◽  
Influenza Viruses ◽  
Study Cohort ◽  
Rt Pcr ◽  
Rna Detection

Abstract Background.  We aimed to explore the detection profile of influenza viruses following live-attenuated intranasal influenza vaccination (LAIV) in children aged 2–19 years with and without cystic fibrosis (CF). Methods.  Before the 2013–2014 influenza season, flocked nasal swabs were obtained before vaccination and 4 times in the week of follow-up from 76 participants (nCF: 57; nhealthy: 19). Influenza was detected by reverse transcription polymerase chain reaction (RT-PCR) assays. A Bayesian hierarchical logistic regression model was used to estimate the effect of CF status and age on influenza detection. Results.  Overall, 69% of the study cohort shed influenza RNA during follow-up. The mean duration of RT-PCR detection was 2.09 days (95% credible interval [CrI]: 1.73–2.48). The odds of influenza RNA detection on day 1 following vaccination decreased with age in years (odds ratio [OR]: 0.82 per year; 95% CrI: 0.70–0.95), and subjects with CF had higher odds of influenza RNA detection on day 1 of follow-up (OR: 5.09; 95% CrI: 1.02–29.9). Conclusion.  Despite the small sample size, our results indicate that LAIV vaccine strains are detectable during the week after LAIV, mainly in younger individuals and vaccinees with CF. It remains unclear whether recommendations for avoiding contact with severely immunocompromised patients should differ for these groups.

scholarly journals From positive to negative: a time to event analysis in Regione Lombardia.

2020 ◽  
Author(s):  
Gabriele Del Castillo ◽  
Ambra Castrofino ◽  
Francesca Grosso ◽  
Giuseppe Marano ◽  
Patrizia Boracchi ◽  
...  
Keyword(s):  
Time Span ◽  
Positive Patient ◽  
Event Analysis ◽  
Time To Event ◽  
Rt Pcr ◽  
Rna Detection ◽  
Time To Death ◽  
Cumulative Probabilities

Abstract Objectives. To assess the time span from positive to negative SARS-CoV-2 RNA detection by RT-PCR, and to evaluate the reliability of the test-based criteria as the required condition for the reintroduction of the asymptomatic SARS-CoV-2 positive patient in the community. Methods. We used information concerning negativization and the respective times. Cumulative probabilities of negativization during the follow-up were evaluated by Crude Cumulative Incidences (CCIs). Non-parametric estimates of CCIs and respective 95% C.I.s were obtained.Results. We report only the results for 52,186 individuals. 33486 subjects resulted negative or potentially negative with a CCI of 75.2% at 70 days from the first swab (95% CI: 74.8% to 75.7%). 11,000 subjects deceased before 14/05/2020 without diagnosis of negative status (CCI 21.9%; 95% CI: 21.5% to 22.3%), at 56 days from the first swab (maximum observed time to death).Conclusions. SARS-CoV-2 positivity is a condition that frequently lasts more than 30 days. Since the determination of isolation based only on a status of positivity could be excessive, more solid studies are required to determinate the significance of a prolonged state of positivity and the consequences on the policies of dismission of quarantine and isolation.

scholarly journals From positive to negative: a time to event analysis in Regione Lombardia.

2020 ◽  
Author(s):  
Gabriele Del Castillo ◽  
Ambra Castrofino ◽  
Francesca Grosso ◽  
Giuseppe Marano ◽  
Patrizia Boracchi ◽  
...  
Keyword(s):  
Time Span ◽  
Positive Patient ◽  
Event Analysis ◽  
Time To Event ◽  
Rt Pcr ◽  
Rna Detection ◽  
Time To Death ◽  
Cumulative Probabilities ◽  
Non Parametric

Abstract Objectives. To assess the time span from positive to negative SARS-CoV-2 RNA detection by RT-PCR, and to evaluate the reliability of the test-based criteria as the required condition for the reintroduction of the asymptomatic SARS-CoV-2 positive patient in the community. Methods. We used information concerning negativization and the respective times. Cumulative probabilities of negativization during the follow-up were evaluated by through Crude Cumulative Incidences (CCIs). Non-parametric estimates of CCIs and respective 95% C.I.s were obtained.Results. We report only the results for 52,186 individuals. 33486 subjects resulted negative or potentially negative with a CCI of 75.2% at 70 days from the first swab (95% CI: 74.8% to 75.7%). 11,000 subjects deceased before 14/05/2020 without diagnosis of negative status (CCI 21.9%; 95% CI: 21.5% to 22.3%) at 56 days from the first swab (maximum observed time to death).Conclusions. SARS-CoV-2 positivity is a condition that frequently lasts more than 30 days. Since isolation based only on positivity status could be excessive, more solid studies are required to determine a single internationally accepted policy regarding the dismission of quarantine and isolation.

scholarly journals High prevalence of SARS-CoV-2 antibodies in care homes affected by COVID-19; a prospective cohort study in England

2020 ◽  
Author(s):  
Shamez N Ladhani ◽  
Anna J Jeffery-Smith ◽  
Monika Patel ◽  
Roshni Janarthanan ◽  
Jonathan Fok ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Care Homes ◽  
Rt Pcr ◽  
Staff Members ◽  
Institutional Settings ◽  
High Prevalence ◽  
Almost All ◽  
Antibody Levels ◽  
Very High

Background: We investigated six London care homes experiencing a COVID-19 outbreak and found very high rates of SARS-CoV-2 infection among residents and staff. Here we report follow-up serological analysis in these care homes five weeks later. Methods: Residents and staff had a convalescent blood sample for SARS-CoV-2 antibody levels and neutralising antibodies by SARS-COV-2 RT-PCR five weeks after the primary COVID-19 outbreak investigation. Results: Of the 518 residents and staff in the initial investigation, 208/241 (86.3%) surviving residents and 186/254 (73.2%) staff underwent serological testing. Almost all SARS-CoV-2 RT-PCR positive residents and staff were antibody positive five weeks later, whether symptomatic (residents 35/35, 100%; staff, 22/22, 100%) or asymptomatic (residents 32/33, 97.0%; staff 21/22, 95.1%). Symptomatic but SARS-CoV-2 RT-PCR negative residents and staff also had high seropositivity rates (residents 23/27, 85.2%; staff 18/21, 85.7%), as did asymptomatic RT-PCR negative individuals (residents 62/92, 67.3%; staff 95/143, 66.4%). Neutralising antibody was present in 118/132 (89.4%) seropositive individuals and was not associated with age or symptoms. Ten residents (10/108, 9.3%) remained RT-PCR positive, but with lower RT-PCR cycle threshold values; all 7 tested were seropositive. New infections were detected in three residents and one staff member. Conclusions: RT-PCR testing for SARS-CoV-2 significantly underestimates the true extent of an outbreak in institutional settings. Elderly frail residents and younger healthier staff were equally able to mount robust and neutralizing antibody responses to SARS-CoV-2. More than two-thirds of residents and staff members had detectable antibodies against SARS-CoV-2 irrespective of their nasal swab RT-PCR positivity or symptoms status.

scholarly journals Persistent SARS-CoV-2 replication in severe COVID-19

2020 ◽  
Author(s):  
María Dolores Folgueira ◽  
Joanna Luczkowiak ◽  
Fátima Lasala ◽  
Alfredo Pérez-Rivilla ◽  
Rafael Delgado
Keyword(s):  
Cell Culture ◽  
Cytopathic Effect ◽  
Severe Pneumonia ◽  
Infective Virus ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Rna Detection ◽  
Ct Value ◽  
Determining Factor

AbstractBackgroundThe diagnosis of SARS-CoV-2 infection is based on viral RNA detection by real-time RT-PCR (rRT-PCR) in respiratory samples. This detection can remain positive for weeks without implying virus viability.MethodsWe have performed cell culture to assess viral replication in 106 respiratory samples rRT-PCR positive for SARS-CoV-2 from 105 patients with COVID-19. Fifty were samples from 50 patients with mild forms of COVID-19 who did not require hospital admission. Fifty-six samples were obtained from 55 hospitalized patients with severe pneumonia. Samples were obtained at different time points covering the time from clinical diagnosis to the follow up during hospital care.ResultsIn 49 samples (49/106, 46.2%) a cytopathic effect (CPE) was detected in cell culture. Our study demonstrates that while in patients with mild COVID-19, viral viability is maintained in fact up to 10 days in patients with severe COVID-19 the virus can remain viable for up to 32 days after the onset of symptoms. Patients with severe COVID-19 as compared with mild cases, presented infective virus in a significantly higher proportion in samples with moderate or low viral load (Ct value > 26): 22/46 (47.8%) versus 7/38 (18.4%), (p <0.01), respectively.ConclusionsPersistent SARS-CoV-2 replication could be demonstrated in severe COVID-19 cases for periods up to 32 days after the onset of symptoms and even at high Ct values. COVID-19 severity is a more determining factor for viral viability than the time elapsed since the onset of symptoms or the Ct value obtained in the RT-PCR assay.

scholarly journals Association between Clinical, Laboratory and CT Characteristics and RT-PCR Results in the Follow-up of COVID-19 patients

2020 ◽  
Author(s):  
Hang Fu ◽  
Huayan Xu ◽  
Na Zhang ◽  
Hong Xu ◽  
Zhenlin Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Reverse Transcriptase ◽  
Clinical Laboratory ◽  
Chest Ct ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Radiological Data ◽  
Polymerase Chain ◽  
Ct Features

AbstractBackgroundSince December 2019, more than 100,000 coronavirus disease 2019 (COVID-19) patients have been confirmed globally based on positive viral nucleic acids with real-time reverse transcriptase-polymerase chain reaction (RT-PCR). However, the association between clinical, laboratory and CT characteristics and RT-PCR results is still unclear. We sought to examine this association in detail, especially in recovered patients.MethodsWe analysed data from 52 confirmed patients who had been discharged with COVID-19. The clinical, laboratory, and radiological data were dynamically recorded and compared with the admission and follow-up RT-PCR results.ResultsIn this cohort, 52 admitted COVID-19 patients who had confirmed positive RT-PCR results were discharged after 2 rounds of consecutively negative RT-PCR results. Compared with admission levels, CRP levels (median 4.93 mg/L [IQR: 1.78-10.20]) decreased significantly (p<0.001). and lymphocyte counts (median 1.50×109/L [IQR: 1.11-1.88]) increased obviously after obtaining negative RT-PCR results (p<0.001). Additionally, substantially improved inflammatory exudation was observed on chest CT except for 2 progressed patients. At the two-week follow-up after discharge, 7 patients had re-positive RT-PCR results, including the abovementioned 2 progressed patients. Among the 7 patients, new GGO was demonstrated in 2 patients. There were no significant differences in CPR levels or lymphocyte counts when comparing the negative and re-positive PCT results (all p >0.05).ConclusionHeterogeneity between CT features and RT-PCR results was found in COVID-19, especially in some recovered patients with negative RT-PCR results. Our study highlights that both RT-PCR and chest CT should be considered as the key determinants for the diagnosis and management of COVID-19 patients.

scholarly journals Multiplex Antibody Analysis of IgM, IgA and IgG to SARS-CoV-2 in Saliva and Serum from Infected Children and their Close Contacts

2021 ◽  
Author(s):  
Carlota Dobaño ◽  
Selena Alonso ◽  
Marta Vidal ◽  
Alfons Jiménez ◽  
Rocío Rubio ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
Antibody Detection ◽  
Rt Pcr ◽  
Non Invasive ◽  
Pcr Diagnosis ◽  
Pediatric Populations ◽  
Coronavirus Infection ◽  
Asymptomatic Individuals ◽  
Antibody Levels

ABSTRACTCOVID-19 affects children to a lesser extent than adults but they can still get infected and transmit SARS-CoV-2 to their contacts. Field deployable non-invasive sensitive diagnostic techniques are needed to evaluate the infectivity dynamics of the coronavirus in pediatric populations and guide public health interventions.We evaluated the utility of high-throughput Luminex-based assays applied to saliva samples to quantify IgM, IgA and IgG antibodies against five SARS-CoV-2 spike (S) and nucleocapsid (N) antigens in the context of a contacts and infectivity longitudinal study. We compared the antibody levels obtained in saliva versus serum/plasma samples from a group of children and adults tested weekly by RT-PCR over 35 days and diagnosed as positive (n=58), and a group of children and adults who consistently tested negative over the follow up period (n=61), in the Summer of 2020 in Barcelona, Spain.Antibody levels in saliva samples from individuals with confirmed RT-PCR diagnosis of SARS-CoV-2 infection were significantly higher than in negative individuals and correlated with those measured in sera/plasmas. Higher levels of anti-S IgG were found in asymptomatic individuals that could indicate protection against disease in infected individuals. Higher anti-S IgG and IgM levels in serum/plasma and saliva, respectively, in infected children compared to infected adults could also be related to stronger clinical immunity in them. Among infected children, males had higher levels of saliva IgG to N and RBD than females. Despite overall correlation, individual clustering analysis suggested that responses that may not be detected in blood could be patent in saliva, and vice versa, and therefore that both measurements are complementary.In addition to serum/plasma, measurement of SARS-CoV-2-specific saliva antibodies should be considered as a complementary non-invasive assay to better estimate the percentage of individuals who have experienced coronavirus infection. Saliva antibody detection could allow determining COVID-19 prevalence in pediatric populations, alternative to bleeding or nasal swab, and serological diagnosis following vaccination.

Prospective clinical and serological follow-up in early childhood reveals a high rate of subclinical RSV infection and a relatively high reinfection rate within the first 3 years of life

2016 ◽  
Vol 144 (8) ◽  
pp. 1622-1633 ◽  
Author(s):  
A. KUTSAYA ◽  
T. TEROS-JAAKKOLA ◽  
L. KAKKOLA ◽  
L. TOIVONEN ◽  
V. PELTOLA ◽  
...  
Keyword(s):  
Early Childhood ◽  
Primary Infection ◽  
Healthy Children ◽  
Rt Pcr ◽  
Reinfection Rate ◽  
Follow Up Study ◽  
Rsv Infection ◽  
Tract Infections ◽  
Antibody Levels

SUMMARYChildren encounter repeated respiratory tract infections during their early life. We conducted a prospective clinical and serological follow-up study to estimate the respiratory syncytial virus (RSV) primary infection and reinfection rates in early childhood. Sera were collected from 291 healthy children at the ages of 13, 24 and 36 months and antibody levels against RSV antigens were determined by enzyme immunoassay. The RT–PCR method was also used for identifying the possible presence of RSV in symptomatic patients. At ages 1, 2 and 3 years, 37%, 68% and 86%, respectively, of studied children were seropositive for RSV. In children seropositive at age 1 year, RSV reinfection rate was at least 37%. Only one of reinfected children showed evidence for a third reinfection by age 3 years. Of children who turned RSV seropositive between ages 1 and 2 years, the reinfection rate was 32% during the third year of life. The mean antibody levels at primary infection were very similar in all age groups. The average decrease of antibody levels was 25–30% within a year. In 66 cases RSV infection was identified by RT–PCR. RSV infection rate in early childhood is 86% and reinfection rate is around 35%. This prospective serological follow-up study also provided evidence for the presence of RSV infections in children that did not show clinical signs warranting RSV RNA detection.

1089: Prognostic Value of Molecular Staging of Bladder Cancer with RT -PCR Assay for KRT20: Results at 5 Year-Follow-up

2007 ◽  
Vol 177 (4S) ◽  
pp. 360-360
Author(s):  
Ana Agud ◽  
Maria J. Ribal ◽  
Lourdes Mengual ◽  
Mercedes Marin-Aguilera ◽  
Laura Izquierdo ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Prognostic Value ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Molecular Staging

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

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