Factores asociados a la positividad de la PCR para SARS-CoV-2 en menores de 15 años / Related PCR positivity factors for SARS-CoV-2 in children under 15 years of age / Fatores associados à positividade da PCR para SARS-CoV-2 em crianças menores de 15 anos de idade

Introducción: la infección por SARS-CoV-2 en niños representa un porcentaje menor en la incidencia global de pacientes infectados por este virus. La prueba de reacción en cadena de polimerasa (PCR) para SARS-CoV-2 en muestra de secreciones nasofaríngeas es considerada como estándar de referencia, con niveles de sensibilidad y especificidad superiores a otras técnicas. Objetivo: describir las características de los pacientes menores de 15 años a los que se realizó PCR para SARS-CoV-2 en un prestador privado de salud del interior del país entre el 1° julio 2020 y el 30 de abril 2021. Analizar posibles factores asociados a la positividad de la prueba. Describir las características de los casos con PCR positiva Metodología: estudio observacional prospectivo con un análisis retrospectivo de tipo caso-control, a partir del seguimiento de una cohorte de menores de 15 años a los que se les realizó una prueba de PCR para SARS-CoV-2 en el período analizado, en un prestador integral de salud privado del interior del país. Se recabaron datos durante el seguimiento de los pacientes de acuerdo a un protocolo institucional que incluye: datos patronímicos, causa de la solicitud de la PCR, características del contacto, resultado de PCR y umbral de ciclo (CT), manifestaciones clínicas y evolución. Resultados: se solicitaron 2.361 PCR a menores de 15 años (15% del total de las PCR de la institución). Promedio de edad: 8,6 años (rango 7 días-14 años y 11 meses); 49% niñas y 51% varones. Motivo de solicitud de la prueba: 78,4% para estudio de contacto, 14,3% por síntomas sin noción de contacto y 7,3% previo a ingreso hospitalario (de urgencia o coordinación). Porcentaje de positividad de todo el período: 14,7%, con una importante variabilidad mensual (5,6% en diciembre y 27% en abril). La PCR fue positiva en 346 casos, con CT promedio de 27, y rango entre 16,8 y 37,3. No se encontraron diferencias estadísticas en relación a la edad y sexo entre casos positivos y negativos. Solo un caso fue PCR positivo previo al ingreso hospitalario (OR 0,03; IC 95% 0,004-0,22) y 20 de las 611 PCR solicitadas por contacto institucional (escolar, deportivo, etc.), siendo la diferencia estadísticamente significativa cuando el caso era mayor de 15 años (p 0,029). Del estudio retrospectivo de casos (PCR positiva) y controles (PCR negativa) surge una asociación estadísticamente significativa (p<0,000001) con la causa de solicitud por contacto en comparación con otra causa (OR 5,2; IC 95% 3,28-8,26), que el caso índice sea mayor de 15 años (OR 4,57 IC 95% 2,95 - 7,10) y que sea conviviente (OR 5,28 IC 95% 3,97 - 7,04). No hubo hospitalizaciones ni fallecimientos por COVID en la población analizada. Conclusiones: el testeo de niños y adolescentes en busca de COVID 19 continúa siendo una estrategia válida cuando existen síntomas sugestivos o contacto con un caso confirmado. En este estudio, los niños con antecedente de contacto con conviviente positivo, y mayor de 15 años, mostraron una mayor proporción de resultados positivos de PCR para SARS-CoV-2.

Introduction: the SARS-CoV-2 infection has shown a lower percentage in children compared to the global incidence of patients infected by this virus. The Polymerase Chain Reaction (PCR) test for SARS-CoV-2 in a sample of nasopharyngeal secretions is considered the reference standard test, and it has shown higher sensitivity and specificity levels than other techniques. Objective: describe the characteristics of patients under 15 years of age who underwent PCR for SARS-CoV-2 in a private health provider in the interior of the country between July 1, 2020 and April 30, 2021. Analyze possible factors linked to test positivity. Describe the characteristics of cases with positive PCR Methodology: prospective observational study with a retrospective case-control analysis based on the follow-up of a cohort of children under 15 years of age who underwent a PCR test for SARS-CoV-2 in the period analyzed, at a private health provider in the interior of Uruguay. Data were collected during patients' follow-up according to the institutional protocol that includes: personal data, reason for requesting the PCR, contact data, PCR result and cycle threshold (CT), clinical manifestations and evolution. Results: 2,361 PCRs were performed to children of under 15 years of age (15% of all PCRs in the institution). Average age 8.6 years (range 7 days - 14 years and 11 months); 49% girls and 51% boys. Reason for requesting the test: 78.4% due to previous contact, 14.3% due to symptoms without knowledge of contact and 7.3% prior to hospital admission (emergency or scheduled). Positivity percentage for the entire period 14.7% with significant monthly variability (5.6% in December and 27% in April). The PCR was positive in 346 cases, with a mean CT of 27, and a range between 16.8 and 37.3. No statistical differences were found regarding age and sex between positive and negative cases. Only 1 case was positive PCR prior to hospital admission (OR 0.03 95% CI 0.004 - 0.22) and 20 out of the 611 PCR were requested due to prior institutional contact (school, sports centers, etc.), the difference being statistically significant when the patient was older than 15 years (p 0.029). From the retrospective study of cases (PCR positive) and controls (PCR negative), a statistically significant link (p<0.000001) arose regarding: when the request resulted from a prior contact compared to other causes (OR 5.2 CI 95% 3.28-8.26), when the index case was older than 15 years of age (OR 4.57 95% CI 2.95-7.10) and when the patient and the contact had cohabited (OR 5.28 95% CI 3.97-7.04). There were no hospitalizations or deaths from COVID in the population analyzed. Conclusions: testing children and adolescents for COVID 19 continues to be a valid strategy in case of suggestive symptoms or contact with a confirmed positive case. In this study, children with a history of contact with a positive case, and older than 15 years, showed a higher proportion of positive PCR results for SARS-CoV-2.

Introdução: a infecção por SARS-CoV-2 em crianças representa um percentual menor do que na incidência global de pacientes infectados por esse vírus. O teste de reação em cadeia da polimerase (PCR) para SARS-CoV-2 em uma amostra de secreções nasofaríngeas é considerado o padrão de referência, com níveis de sensibilidade e especificidade mais elevados do que outras técnicas. Objetivo: descrever as características dos pacientes menores de 15 anos de idade que realizaram PCR para SARS-CoV-2 em uma prestadora de saúde privada do interior do país entre 1º de julho de 2020 e 30 de abril de 2021. Analisar possíveis fatores associados à positividade do teste. Descrever as características dos casos com PCR positivo. Metodologia: estudo observacional prospectivo com análise retrospectiva caso-controle a partir do acompanhamento de uma coorte de crianças menores de 15 anos que realizaram teste de PCR para SARS-CoV 2 no período analisado, em uma assistência médica de saúde no interior do país. Os dados foram coletados durante o acompanhamento dos pacientes de acordo com o protocolo institucional e incluíram: informação pessoal, motivo da solicitação do PCR, características do contato, resultado do PCR e limiar de ciclo (CT), manifestações clínicas e evolução. Resultados: foram solicitados 2.361 PCRs de menores de 15 anos (15% do total de PCRs da instituição). Idade média 8,6 anos (variação 7 dias - 14 anos e 11 meses); 49% meninas e 51% meninos. Motivo do pedido do exame: 78,4% por estudo de contato, 14,3% por sintomas sem conhecimento de contato e 7,3% antes da internação (por emergência ou coordenação). Porcentagem de positividade para todo o período 14,7% com significativa variabilidade mensal (5,6% em dezembro e 27% em abril). O PCR foi positivo em 346 casos, com média de TC de 27 e variação entre 16,8 e 37,3. Não foram encontradas diferenças estatísticas em relação à idade e sexo entre os casos positivos e negativos. Apenas 1 caso foi PCR positivo antes da admissão hospitalar (OR 0,03 IC 95% 0,004 - 0,22) e 20 dos 611 PCR solicitados por contato institucional (escola, centros de esportes, etc.), sendo a diferença estatisticamente significativa para os casos que tinham mais de 15 anos de idade (p 0,029). Do estudo retrospectivo de casos (PCR positivo) e controles (PCR negativo), emergiu uma associação estatisticamente significativa (p <0,000001) quando: a causa da solicitação do teste tinha sido um contato positivo prévio em relação a outra causa (OR 5,2 IC 95% 3,28 - 8,26), e quando o caso índice era mais velho do que 15 anos (OR 4,57 IC 95% 2,95 - 7,10) ou coabitava com o paciente (OR 5,28 IC 95% 3,97 - 7,04). Não houve internações ou óbitos por COVID na população analisada. Conclusões: a testagem de crianças e adolescentes em busca de COVID-19 continua sendo uma estratégia válida quando há sintomas sugestivos ou contato com um caso positivo confirmado. Neste estudo, crianças com histórico de contato com casos positivos na mesma casa e mais velhos do que 15 anos de idade apresentaram maior proporção de resultados positivos de PCR para SARS-CoV-2.

Performances of rapid and connected salivary RT-LAMP diagnostic test for SARS-CoV-2 infection in ambulatory screening.

In the context of social events reopening and economic relaunch, sanitary surveillance of SARS-CoV-2 infection is still required. Here, we evaluated the diagnostic performances of a rapid, extraction-free and connected reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay on saliva. Nasopharyngeal (NP) swabs and saliva from 443 outpatients were collected simultaneously and tested by reverse-transcription quantitative PCR (RT-qPCR) as reference standard test. Seventy-one individuals (16.0%) were positive by NP and/or salivary RT-qPCR. Sensitivity and specificity of salivary RT-LAMP were 85.9% (95%CI 77.8-94.0%) and 99.5% (98.7-100%), respectively. Performances were similar for symptomatic and asymptomatic participants. Moreover, SARS-CoV-2 genetic variants were analyzed and no dominant mutation in RT-LAMP primer region was observed during the period of the study. We demonstrated that this RT-LAMP test on self-collected saliva is reliable for SARS-CoV-2 detection. This simple connected test with optional automatic results transfer to health authorities is unique and opens the way to secure professional and social events in actual context of economics restart.

Increased complications in patients who test COVID-19 positive after elective surgery and implications for pre and postoperative screening.

BACKGROUND: The COVID-19 pandemic has necessitated the adoption of protocols to minimize risk of periprocedural complications associated with SARS-CoV-2 infection. This typically involves a preoperative symptom screen and nasal swab RT-PCR test for viral RNA. Asymptomatic patients with a negative COVID-19 test are cleared for surgery. However, little is known about the rate of postoperative COVID-19 positivity among elective surgical patients, risk factors for this group and rate of complications. METHODS: This prospective multicenter study included all patients undergoing elective surgery at 170 Veterans Health Administration (VA) hospitals across the United States. Patients were divided into groups based on first positive COVID-19 test within 30 days after surgery (COVID[-/+]), before surgery (COVID[+/-]) or negative throughout (COVID[-/-]). The cumulative incidence, risk factors for and complications of COVID[-/+], were estimated using univariate analysis, exact matching, and multivariable regression. RESULTS: Between March 1 and December 1, 2020 90,093 patients underwent elective surgery. Of these, 60,853 met inclusion criteria, of which 310 (0.5%) were in the COVID[-/+] group. Adjusted multivariable logistic regression identified female sex, end stage renal disease, chronic obstructive pulmonary disease, congestive heart failure, cancer, cirrhosis, and undergoing neurosurgical procedures as risk factors for being in the COVID[-/+] group. After matching on current procedural terminology code and month of procedure, multivariable Poisson regression estimated the complication rate ratio for the COVID[-/+] group vs. COVID[-/-] to be 8.4 (C.I. 4.9-14.4) for pulmonary complications, 3.0 (2.2, 4.1) for major complications, and 2.6 (1.9, 3.4) for any complication. DISCUSSION: Despite preoperative COVID-19 screening, there remains a risk of COVID infection within 30 days after elective surgery. This risk is increased for patients with a high comorbidity burden and those undergoing neurosurgical procedures. Higher intensity preoperative screening and closer postoperative monitoring is warranted in such patients because they have a significantly elevated risk of postoperative complications.

Clinical Utility of COVID-19 Real Time-Polymerase Chain Reaction Testing of Ocular Tissues of Non-COVID-19 Cornea Donors Deemed Suitable for Corneal Retrieval and Transplantation.

PURPOSE: The purpose of this study was to evaluate the prevalence of SARS-CoV-2 in human postmortem ocular tissues of asymptomatic donors and its implications on our eye banking protocols. METHODS: The expression of SARS-CoV-2 RNA was assessed by reverse transcription-polymerase chain reaction in corneal rims and conjunctival tissues from 100 donors who were found suitable for transplantation as per the donor screening guidelines of the Global Alliance of Eye Bank Associations. The donor's clinical history and cause of death were assessed for secondary analysis. RESULTS: Of 200 ocular tissues (100 corneal and 100 conjunctival) from the same 1 eye of 100 surgical-intended donors, between September 2020 and April 2021, the overall positivity rate for SARS-CoV-2 was ∼1% (2/200). Both the ocular samples that tested positive were conjunctival biopsies (2/100, 2%), whereas corneal samples were negative (0/100, 0%) in both donors. The causes of donor death were trauma in 51 donors, suicide in 33, cardiac arrest in 7, electric shock in 5, metabolic cause in 2, malignancy in 1, and snake bite in 1. None of the donors had a medical history suggestive of COVID infection or possible contact. None of the recipients from the donors were reported to have any systemic adverse event after keratoplasty until the follow-up of 6 weeks. CONCLUSIONS: The overall prevalence of SARS-CoV-2 was 1% (2% for conjunctival and 0% for corneal samples, P value = 0.5) in the donors who were found suitable for cornea recovery and transplantation. The findings of exceptionally low positive rates in our samples validate the criticality of history-based donor screening and do not support the necessity of postmortem PCR testing as a criterion for procurement and subsequent use for corneal transplantation.

Final efficacy analysis, interim safety analysis, and immunogenicity of a single dose of recombinant novel coronavirus vaccine (adenovirus type 5 vector) in adults 18 years and older: an international, multicentre, randomised, double-blinded, placebo-controlled phase 3 trial.

BACKGROUND: The Ad5-nCoV vaccine is a single-dose adenovirus type 5 (Ad5) vectored vaccine expressing the SARS-CoV-2 spike protein that was well-tolerated and immunogenic in phase 1 and 2 studies. In this study, we report results on the final efficacy and interim safety analyses of the phase 3 trial. METHODS: This double-blind, randomised, international, placebo-controlled, endpoint-case driven, phase 3, clinical trial enrolled adults aged 18 years older at study centres in Argentina, Chile, Mexico, Pakistan, and Russia. Participants were eligible for the study if they had no unstable or severe underlying medical or psychiatric conditions; had no history of a laboratory-confirmed SARS-CoV-2 infection; were not pregnant or breastfeeding; and had no previous receipt of an adenovirus-vectored, coronavirus, or SARS-CoV-2 vaccine. After informed consent was obtained, 25 mL of whole blood was withdrawn from all eligible participants who were randomised in a 1:1 ratio to receive a single intramuscular dose of 0·5 mL placebo or a 0·5 mL dose of 5 × 1010 viral particle (vp)/mL Ad5-nCoV vaccine; study staff and participants were blinded to treatment allocation. All participants were contacted weekly by email, telephone, or text message to self-report any symptoms of COVID-19 illness, and laboratory testing for SARS-CoV-2 was done for all participants with any symptoms. The primary efficacy objective evaluated Ad5-nCoV in preventing symptomatic, PCR-confirmed COVID-19 infection occurring at least 28 days after vaccination in all participants who were at least 28 days postvaccination on Jan 15, 2021. The primary safety objective evaluated the incidence of any serious adverse events or medically attended adverse events postvaccination in all participants who received a study injection. This trial is closed for enrolment and is registered with ClinicalTrials.gov (NCT04526990). FINDINGS: Study enrolment began on Sept 22, 2020, in Pakistan, Nov 6, 2020, in Mexico, Dec 2, 2020, in Russia and Chile, and Dec 17, 2020, in Argentina; 150 endpoint cases were reached on Jan 15, 2021, triggering the final primary efficacy analysis. One dose of Ad5-nCoV showed a 57·5% (95% CI 39·7-70·0, p=0·0026) efficacy against symptomatic, PCR-confirmed, COVID-19 infection at 28 days or more postvaccination (21 250 participants; 45 days median duration of follow-up [IQR 36-58]). In the primary safety analysis undertaken at the time of the efficacy analysis (36 717 participants), there was no significant difference in the incidence of serious adverse events (14 [0·1%] of 18 363 Ad5-nCoV recipients and 10 [0·1%] of 18 354 placebo recipients, p=0·54) or medically attended adverse events (442 [2·4%] of 18 363 Ad5-nCoV recipients and 411 [2·2%] of 18 354 placebo recipients, p=0·30) between the Ad5-nCoV or placebo groups, or any serious adverse events considered related to the study product (none in both Ad5-nCoV and placebo recipients). In the extended safety cohort, 1004 (63·5%) of 1582 of Ad5-nCoV recipients and 729 (46·4%) of 1572 placebo recipients reported a solicited systemic adverse event (p<0·0001), of which headache was the most common (699 [44%] of Ad5-nCoV recipients and 481 [30·6%] of placebo recipients; p<0·0001). 971 (61·3%) of 1584 Ad5-nCoV recipients and 314 (20·0%) of 1573 placebo recipients reported an injection-site adverse event (p<0·0001), of which pain at the injection site was the most frequent; reported by 939 (59%) Ad5-nCoV recipients and 303 (19%) placebo recipients. INTERPRETATION: One dose of Ad5-nCoV is efficacious and safe in healthy adults aged 18 years and older. FUNDING: CanSino Biologics and the Beijing Institute of Biotechnology.

Molecular testing and analysis of disease spreading during the emergence of COVID-19 in Macaé, the Brazilian National Capital of Oil.

The Brazilian strategy to overcome the spread of COVID-19 has been particularly criticized due to the lack of a national coordinating effort and an appropriate testing program. Here, a successful approach to control the spread of COVID-19 transmission is described by the engagement of public (university and governance) and private sectors (hospitals and oil companies) in Macaé, state of Rio de Janeiro, Brazil, a city known as the National Oil Capital. In 2020 between the 17th and 38th epidemiological week, over two percent of the 206,728 citizens were subjected to symptom analysis and RT-qPCR testing by the Federal University of Rio de Janeiro, with positive individuals being notified up to 48 h after swab collection. Geocodification and spatial cluster analysis were used to limit COVID-19 spreading in Macaé. Within the first semester after the outbreak of COVID-19 in Brazil, Macaé recorded 1.8% of fatalities associated with COVID-19 up to the 38th epidemiological week, which was at least five times lower than the state capital (10.6%). Overall, considering the successful experience of this joint effort of private and public engagement in Macaé, our data suggest that the development of a similar strategy countrywise could have contributed to a better control of the COVID-19 spread in Brazil. Quarantine decree by the local administration, comprehensive molecular testing coupled to scientific analysis of COVID-19 spreading, prevented the catastrophic consequences of the pandemic as seen in other populous cities within the state of Rio de Janeiro and elsewhere in Brazil.

SARS-CoV2 infection: functional and morphological cardiopulmonary changes in elite handball players.

There is increasing evidence of cardiac involvement post-SARS-CoV-2 infections in symptomatic as well as in oligo- and asymptomatic athletes. This study aimed to characterize the possible early effects of SARS-CoV-2 infections on myocardial morphology and cardiopulmonary function in athletes. Eight male elite handball players (27 ± 3.5 y) with past SARS-CoV-2 infection were compared with four uninfected teammates (22 ± 2.6 y). Infected athletes were examined 19 ± 7 days after the first positive PCR test. Echocardiographic assessment of the global longitudinal strain under resting conditions was not significantly changed (- 17.7% vs. - 18.1%). However, magnetic resonance imaging showed minor signs of acute inflammation/oedema in all infected athletes (T2-mapping: + 4.1 ms, p = 0.034) without reaching the Lake-Louis criteria. Spiroergometric analysis showed a significant reduction in VO2max (- 292 ml/min, - 7.0%), oxygen pulse (- 2.4 ml/beat, - 10.4%), and respiratory minute volume (VE) (- 18.9 l/min, - 13.8%) in athletes with a history of SARS-CoV2 infection (p < 0.05, respectively). The parameters were unchanged in the uninfected teammates. SARS-CoV2 infection caused impairment of cardiopulmonary performance during physical effort in elite athletes. It seems reasonable to screen athletes after SARS-CoV2 infection with spiroergometry to identify performance limitations and to guide the return to competition.

Lack of correlation between the SARS-CoV-2 cycle threshold (Ct ) value and clinical outcomes in patients with COVID-19.

PROBLEM: The utility of the polymerase chain reaction (PCR) cycle threshold (Ct ) values in the management of patients with coronavirus disease 2019 (COVID-19) remains controversial. METHODS: We assessed the correlation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Ct values in nasopharyngeal swab samples with the oxygen requirements at the time of sample collection. Specimens were tested with the Simplexa PCR platform, which targets the SARS-CoV-2 ORF1ab and S genes. RESULTS: We identified 23 COVID-19 patients with 49 Ct values available. While Ct values from ORF1ab and S genes were highly correlated for a given specimen, there was no correlation between Ct values for any of these target genes and the oxygen requirements of the patient at the time of sample collection. We found no differences in the initial nor the nadir Ct values between survivors and non-survivors or mild/moderate versus severe/critical illness at the maximum point of illness. CONCLUSION: SARS-CoV-2 Ct values have limited value in the management of COVID-19.

Cancer and COVID-19: analysis of patient outcomes.

Background: We sought to investigate the outcomes associated with COVID-19 disease in cancer patients. Methods: We conducted a retrospective cohort study of laboratory-confirmed COVID-19 patients. Results: Of the 206 patients included, 57 had at least one preexisting malignancy. Cancer patients were older than noncancer patients. Of the 185 discharged cases, cancer patients had a significantly higher frequency of unplanned reintubation (7.1% vs 0.9%, p < 0.049), and required longer hospital stay (8.58 ± 6.50 days versus 12.83 ± 11.44 days, p < 0.002). Regression analysis revealed that obesity and active smoking were associated with an increased risk of mortality. Conclusion: Outcomes in COVID-19 appear to be driven by obesity as well as active smoking, with no difference in mortality between cancer and noncancer patients.

In this study, we aimed to investigate how COVID-19 affected cancer patients and whether this altered their survival outcomes. To do this, we examined data from a database of patients who have passed through our institution ­ a retrospective cohort analysis. Of the 206 patients we included in the study from this database, 57 had at least one preexisting cancer. Cancer patients tended to be older than noncancer patients. Of the 185 discharged patients, cancer patients required longer hospital stays, but there was no difference in mortality. Disease complications and intensive care unit admission with obesity and active smoking put patients in our cohort at increased risk of death. To conclude, outcomes in COVID-19 patients appear to be driven by obesity as well as active smoking, with no difference in mortality between cancer and noncancer patients.

SARS-CoV-2 PCR positivity rate and seroprevalence of related antibodies among a sample of patients in Cairo: Pre-wave 2 results of a screening program in a university hospital.

BACKGROUND: Research has revealed that asymptomatic and pre-symptomatic infections are important contributors to the transmission of SARS-CoV-2 in populations. In Egypt, the true prevalence of infections is veiled due to the low number of screening tests. The aim of this study was to determine the SARS-CoV-2 PCR positivity rate as well the seroprevalence of the SARS-CoV-2 antibodies before the ultimate development of a second wave of the epidemic in Cairo, Egypt. METHODS: Our study was carried out between May 5 and the end of October 2020. It included all patients requiring admission to Ain Shams University hospitals. An interview questionnaire was used to collect demographic and clinical data. Laboratory tests for all participants included RT-PCR and total antibody assay for SARS-CoV-2. RESULTS: A total of 4,313 subjects were enrolled in our study, with females representing 56% of the sample. Adults and middle-aged individuals represented around 60% of the study sample. The positivity rate of SARS-CoV-2 PCR was 3.84% (95% CI 3.29-4.48), and the SARS-CoV-2 antibody seroprevalence was 29.82% (95% CI: 28.16-31.51). Males showed a higher risk for getting the COVID-19 infection, while middle-age group had significantly higher antibody seroprevalence rates. CONCLUSION: SARS-CoV-2 infection imposes a high burden on the community as detected by high seroprevalence rates.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27 × 10e-4 (according to official data of new cases diagnosed by PCR) to 4.69 × 10e-4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

SARS-CoV-2 screening among people living in homeless shelters in Brussels, Belgium.

BACKGROUND: Subgroups of precarious populations such as homeless people are more exposed to infection and at higher risk of developing severe forms of COVID-19 compared to the general population. Many of the recommended prevention measures, such as social distancing and self-isolation, are not feasible for a population living in shelters characterised by physical proximity and a high population density. The objective of the study was to describe SARS-CoV-2 infection prevalence in homeless shelters in Brussels (Belgium), and to identify risk factors and infection control practices associated with SARS-CoV-2 positivity rates. METHODS: A total of 1994 adults were tested by quantitative PCR tests in 52 shelters in Brussels (Belgium) between April and June, 2020, in collaboration with Doctors of the World. SARS-CoV-2 prevalence is here described site by site, and we identify risk factors associated with SARS-CoV-2 positivity rates. We also investigate associations between seropositivity and reported symptoms. RESULTS: We found an overall prevalence of 4.6% for the period, and a cluster of high rates of SARS-CoV-2 positivity (20-30% in two shelters). Among homeless people, being under 40 years of age (OR (CI95%) 2.3 (1.2-4.4), p = 0.02), having access to urgent medical care (AMU) (OR(CI95%): 2.4 (1.4-4.4)], p = 0.02), and sharing a room with someone who tested positive (OR(CI95%): 5.3 (2.9-9.9), p<0.0001) were factors associated with SARS-CoV-2 positivity rates. 93% of those who tested positive were asymptomatic. CONCLUSION: This study shows high rates of SARS-COV-2 infection positive tests in some shelters, with a high proportion of asymptomatic cases. The survey reveals how important testing and isolation measures are, together with actions taken by medical and social workers during the outbreak.

Effectiveness of BNT162b2 and ChAdOx1 nCoV-19 COVID-19 vaccination at preventing hospitalisations in people aged at least 80 years: a test-negative, case-control study.

BACKGROUND: On Dec 8, 2020, deployment of the first SARS-CoV-2 vaccination authorised for UK use (BNT162b2 mRNA vaccine) began, followed by an adenoviral vector vaccine ChAdOx1 nCoV-19 on Jan 4, 2021. Care home residents and staff, frontline health-care workers, and adults aged 80 years and older were vaccinated first. However, few data exist regarding the effectiveness of these vaccines in older people with many comorbidities. In this post-implementation evaluation of two COVID-19 vaccines, we aimed to determine the effectiveness of one dose in reducing COVID-19-related admissions to hospital in people of advanced age. METHODS: This prospective test-negative case-control study included adults aged at least 80 years who were admitted to hospital in two NHS trusts in Bristol, UK with signs and symptoms of respiratory disease. Patients who developed symptoms before receiving their vaccine or those who received their vaccine after admission to hospital were excluded, as were those with symptoms that started more than 10 days before hospital admission. We did logistic regression analysis, controlling for time (week), sex, index of multiple deprivations, and care residency status, and sensitivity analyses matched for time and sex using a conditional logistic model adjusting for index of multiple deprivations and care residency status. This study is registered with ISRCTN, number 39557. FINDINGS: Between Dec 18, 2020, and Feb 26, 2021, 466 adults were eligible (144 test-positive and 322 test-negative). 18 (13%) of 135 people with SARS-CoV-2 infection and 90 (34%) of 269 controls received one dose of BNT162b2. The adjusted vaccine effectiveness was 71·4% (95% CI 46·5-90·6). Nine (25%) of 36 people with COVID-19 infection and 53 (59%) of 90 controls received one dose of ChAdOx1 nCoV-19. The adjusted vaccine effectiveness was 80·4% (95% CI 36·4-94·5). When BNT162b2 effectiveness analysis was restricted to the period covered by ChAdOx1 nCoV-19, the estimate was 79·3% (95% CI 47·0-92·5). INTERPRETATION: One dose of either BNT162b2 or ChAdOx1 nCoV-19 resulted in substantial risk reductions of COVID-19-related hospitalisation in people aged at least 80 years. FUNDING: Pfizer.

Mortality and critical care unit admission associated with the SARS-CoV-2 lineage B.1.1.7 in England: an observational cohort study.

BACKGROUND: A more transmissible variant of SARS-CoV-2, the variant of concern 202012/01 or lineage B.1.1.7, has emerged in the UK. We aimed to estimate the risk of critical care admission, mortality in patients who are critically ill, and overall mortality associated with lineage B.1.1.7 compared with non-B.1.1.7. We also compared clinical outcomes between these two groups. METHODS: For this observational cohort study, we linked large primary care (QResearch), national critical care (Intensive Care National Audit & Research Centre Case Mix Programme), and national COVID-19 testing (Public Health England) databases. We used SARS-CoV-2 positive samples with S-gene molecular diagnostic assay failure (SGTF) as a proxy for the presence of lineage B.1.1.7. We extracted two cohorts from the data: the primary care cohort, comprising patients in primary care with a positive community COVID-19 test reported between Nov 1, 2020, and Jan 26, 2021, and known SGTF status; and the critical care cohort, comprising patients admitted for critical care with a positive community COVID-19 test reported between Nov 1, 2020, and Jan 27, 2021, and known SGTF status. We explored the associations between SARS-CoV-2 infection with and without lineage B.1.1.7 and admission to a critical care unit (CCU), 28-day mortality, and 28-day mortality following CCU admission. We used Royston-Parmar models adjusted for age, sex, geographical region, other sociodemographic factors (deprivation index, ethnicity, household housing category, and smoking status for the primary care cohort; and ethnicity, body-mass index, deprivation index, and dependency before admission to acute hospital for the CCU cohort), and comorbidities (asthma, chronic obstructive pulmonary disease, type 1 and 2 diabetes, and hypertension for the primary care cohort; and cardiovascular disease, respiratory disease, metastatic disease, and immunocompromised conditions for the CCU cohort). We reported information on types and duration of organ support for the B.1.1.7 and non-B.1.1.7 groups. FINDINGS: The primary care cohort included 198 420 patients with SARS-CoV-2 infection. Of these, 117 926 (59·4%) had lineage B.1.1.7, 836 (0·4%) were admitted to CCU, and 899 (0·4%) died within 28 days. The critical care cohort included 4272 patients admitted to CCU. Of these, 2685 (62·8%) had lineage B.1.1.7 and 662 (15·5%) died at the end of critical care. In the primary care cohort, we estimated adjusted hazard ratios (HRs) of 2·15 (95% CI 1·75-2·65) for CCU admission and 1·65 (1·36-2·01) for 28-day mortality for patients with lineage B.1.1.7 compared with the non-B.1.1.7 group. The adjusted HR for mortality in critical care, estimated with the critical care cohort, was 0·91 (0·76-1·09) for patients with lineage B.1.1.7 compared with those with non-B.1.1.7 infection. INTERPRETATION: Patients with lineage B.1.1.7 were at increased risk of CCU admission and 28-day mortality compared with patients with non-B.1.1.7 SARS-CoV-2. For patients receiving critical care, mortality appeared to be independent of virus strain. Our findings emphasise the importance of measures to control exposure to and infection with COVID-19. FUNDING: Wellcome Trust, National Institute for Health Research Oxford Biomedical Research Centre, and the Medical Sciences Division of the University of Oxford.

Comparison of infection control strategies to reduce COVID-19 outbreaks in homeless shelters in the United States: a simulation study.

BACKGROUND: COVID-19 outbreaks have occurred in homeless shelters across the US, highlighting an urgent need to identify the most effective infection control strategy to prevent future outbreaks. METHODS: We developed a microsimulation model of SARS-CoV-2 transmission in a homeless shelter and calibrated it to data from cross-sectional polymerase chain reaction (PCR) surveys conducted during COVID-19 outbreaks in five homeless shelters in three US cities from March 28 to April 10, 2020. We estimated the probability of averting a COVID-19 outbreak when an exposed individual is introduced into a representative homeless shelter of 250 residents and 50 staff over 30 days under different infection control strategies, including daily symptom-based screening, twice-weekly PCR testing, and universal mask wearing. RESULTS: The proportion of PCR-positive residents and staff at the shelters with observed outbreaks ranged from 2.6 to 51.6%, which translated to the basic reproduction number (R0) estimates of 2.9-6.2. With moderate community incidence (~ 30 confirmed cases/1,000,000 people/day), the estimated probabilities of averting an outbreak in a low-risk (R0 = 1.5), moderate-risk (R0 = 2.9), and high-risk (R0 = 6.2) shelter were respectively 0.35, 0.13, and 0.04 for daily symptom-based screening; 0.53, 0.20, and 0.09 for twice-weekly PCR testing; 0.62, 0.27, and 0.08 for universal masking; and 0.74, 0.42, and 0.19 for these strategies in combination. The probability of averting an outbreak diminished with higher transmissibility (R0) within the simulated shelter and increasing incidence in the local community. CONCLUSIONS: In high-risk homeless shelter environments and locations with high community incidence of COVID-19, even intensive infection control strategies (incorporating daily symptom screening, frequent PCR testing, and universal mask wearing) are unlikely to prevent outbreaks, suggesting a need for non-congregate housing arrangements for people experiencing homelessness. In lower-risk environments, combined interventions should be employed to reduce outbreak risk.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence. / Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

High prevalence of SARS-CoV-2 infection in patients scheduled for digestive endoscopy after the peak of the first wave of the pandemic. / Alta prevalencia de infección por SARS-CoV-2 en pacientes programados para endoscopia digestiva después del pico de la primera onda pandémica.

Healthcare professionals in endoscopy units have a possible risk of SARS-CoV-2 infection by different routes: inhalation of airborne droplets, aerosols, conjunctival contact and faecal-oral transmission. OBJECTIVE: To describe the detection of SARS-CoV-2 in a series of patients scheduled for digestive endoscopy at the Hospital Santa Caterina. Salt. (Girona). METHODS: Descriptive study of a series of cases of patients scheduled for endoscopy during the month of May 2020, when endoscopic activity was resumed after the peak of the pandemic, following SCD, SEED, AEG and ESGE recommendations. We examined nasopharyngeal samples 48-72 hours before the appointment, by RT-PCR, in all patients. RNA extraction was performed using the kits: Qiagen®-adapted, BiosSprint®96-DNA-Blood-Kit (384). For amplification-detection of SARS-CoV-2, methods recommended by the WHO and the CDC were followed. RESULTS: 110 asymptomatic patients without close contact with a positive case in the previous 14 days were scheduled; 105 (96.4%) were negative and five (4.5%) were positive. Two patients developed respiratory symptoms after diagnosis (presymptomatic) and three remained asymptomatic. Allfive5 patients were autochthonous cases with no history of travel or residence in another city or country associated with high prevalence of infection. Four cases were women aged 60-81 years. The N gene was detected in all cases. CONCLUSIONS: A high prevalence of SARS-CoV-2 infection was detected in patients scheduled for digestive endoscopy. Given the risk of transmission to professionals, we consider it advisable to perform SARS-CoV-2 RT-PCR 48-72 hours before the examination in situations of high incidence in the population.

Management of patients with cancer during the COVID-19 pandemic: The Italian perspective on the second wave.

The novel coronavirus disease 2019 (COVID-19) pandemic has been an overwhelming challenge for worldwide health systems. Since the beginning of year 2020, COVID-19 has represented a potential harm for cancer patients and has often hindered oncology care. The Collegio Italiano dei Primari Oncologi Medici (CIPOMO) is an Italian association of head physicians in oncology departments, which promotes working and research activities in oncology on a national basis. During the second wave of COVID-19 pandemic, the CIPOMO promoted a national survey aiming to evaluate the impact of COVID-19 on oncologists' clinical activity and what changes have been made compared with the Italian situation during the first wave of the pandemic. Overall, 138 heads of medical oncology departments participated in this survey: 75 (54%) from the North, 24 (17%) from the Centre and 39 (28%) from the South of Italy and islands. This survey provides an overview of Italian oncologists facing the second wave of COVID-19 pandemic. The lesson learned during the first wave of COVID-19 pandemic has led to a better organisation of clinical activities, and regular testing among healthcare practitioners, with better chances to grant patients' protection. However, the lack of standardised informatic platforms results in serious challenges in replacing frontal visits, often making a concrete reduction of patients' hospital accesses unfeasible. Oncologists need to keep preserving the continuum of care of patients. Standardisation of safety measures, together with the implementation of informatic platforms, can significantly improve oncology pathways during this second wave of COVID-19 pandemic.

Assessing the feasibility and effectiveness of household-pooled universal testing to control COVID-19 epidemics.

Outbreaks of SARS-CoV-2 are threatening the health care systems of several countries around the world. The initial control of SARS-CoV-2 epidemics relied on non-pharmaceutical interventions, such as social distancing, teleworking, mouth masks and contact tracing. However, as pre-symptomatic transmission remains an important driver of the epidemic, contact tracing efforts struggle to fully control SARS-CoV-2 epidemics. Therefore, in this work, we investigate to what extent the use of universal testing, i.e., an approach in which we screen the entire population, can be utilized to mitigate this epidemic. To this end, we rely on PCR test pooling of individuals that belong to the same households, to allow for a universal testing procedure that is feasible with the limited testing capacity. We evaluate two isolation strategies: on the one hand pool isolation, where we isolate all individuals that belong to a positive PCR test pool, and on the other hand individual isolation, where we determine which of the individuals that belong to the positive PCR pool are positive, through an additional testing step. We evaluate this universal testing approach in the STRIDE individual-based epidemiological model in the context of the Belgian COVID-19 epidemic. As the organisation of universal testing will be challenging, we discuss the different aspects related to sample extraction and PCR testing, to demonstrate the feasibility of universal testing when a decentralized testing approach is used. We show through simulation, that weekly universal testing is able to control the epidemic, even when many of the contact reductions are relieved. Finally, our model shows that the use of universal testing in combination with stringent contact reductions could be considered as a strategy to eradicate the virus.

[Intensive covid-19 care in general practice; nationwide registration study, initiated by General Practice Research Consortium Netherlands]. / Intensieve en palliatieve covid-19-zorg door huisarts.

METHOD: Registration system initiated by General Practice Research Consortium Netherlands (GPRC-NL). AIM: To obtain national estimates on clinically suspected Covid-19 mortality in general practice and on intensive and palliative covid-19 care provided by general practitioners (GPs) outside hospital, including palliative medication, availability of personal protective equipment, and reasons for not referring to hospital of vulnerable patients during the first three months of the Covid-19 pandemic in The Netherlands. DESIGN: Nationwide registration study, in which 2.331 GP practices in The Netherlands participated from March-June 2020. METHOD: Registration system initiated by General Practice Research Consortium Netherlands (GPRC-NL) through existing digital referral platform ZorgDomein, in which GPs could report PCR-proven and clinically suspected Covid-19 deceased patients to estimate the impact of the Covid-19 pandemic in primary care. RESULTS: GPs reported 1,566 Covid-19 deceased patients, of which 61% (949/1,566) were clinically suspected but not PCR-tested, with large regional differences, and most deaths being reported in the provinces of Brabant and Limburg. Patients had a median duration from onset of symptoms to death of 8 days and a median age of 87 years. GPs reported 1,030 patients for which they delivered intensive or palliative care, of which 56% had a Clinical Frailty Score higher or equal to six. Most mentioned reason for GPs and patients in the decision not going to hospital were the explicit wish of the patient (59%) and somatic vulnerability (52%). CONCLUSION: GPs provided palliative care to a large number of clinically suspected Covid-19 vulnerable patients with large regional differences across The Netherlands. Reported GPs' and patients' considerations to refrain from hospital care can be used to guide future primary care for vulnerable Covid-19 patients.