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Background/Case Studies: Our blood establishment recently introduced systematic nucleic acid testing (NAT) for parvovirus B19 and hepatitis A virus (HAV). This change was mainly driven by the regulatory requirement to test our recovered and source plasma for parvovirus. One recent case of transmission of parvovirus B19 by transfusion was identified in 2019 in our jurisdiction and caused transient aplastic crisis in a patient with sickle cell disease. Hepatitis A is rare and most cases are imported, with an annual rate of 0, 55/100,000. Universal vaccination for hepatitis A was introduced in 2008 at age 9, so that most adults older than 23 are not vaccinated. We present our experience after one year during which we systematically screened our donors for these two infections. Study Design/Methods: Donations were tested in pools of 16 using the Procleix Parvo/HAV Assay on the Procleix Panther System (Grifols). For parvovirus B19, the threshold for positivity was set at 10,000 international units/ mL. Positive cases for each virus were reviewed, and positivity rates were calculated. Results/Findings: Since the introduction of both assays on 12-06-2020, 457,376 products have been tested. Only one was positive for parvovirus B19 (0.22/100,000), and three were positive for hepatitis A (0.66/100,000). All three individuals with hepatitis A were asymptomatic and did not develop any symptoms during follow-up. Neither of them had travelled nor had risk factors for hepatitis A. They all had a recent history of hepatitis A vaccination in the days prior to the donation (Havrix: 2 days and 1 day, Twinrix: 6 days). All three NAT-positive samples were sent for genotyping, but viral loads were too low for sequencing. Conclusion(s): The rate of parvovirus B19 positivity was much lower than expected, possibly because of the sanitary measures during the SARS-CoV-2 pandemic. The three individuals who tested positive for hepatitis A were presumably false positives due to recent vaccination with inactivated viral strains. We introduced a seven-day deferral after HAV vaccination to minimize the negative impacts of false-positive results.
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Background. One of the most striking observations of the COVID-19 pandemic has been the difference in infection among children vs. adults. Overall, children with SARS-CoV-2 infection generally had milder disease compared to adults, though the cause is not clear. The objective of this study was to compare the humoral response to infection in children vs. adults of a same family. Methods. We performed a prospective cohort study at Sainte-Justine University Health Center in Montreal, Canada from July 2020 to March 2021. Children with a positive SARS-CoV-2 PCR were recruited from the COVID-19 clinic (index case), enrollment was offered to all household members. Serum IgG against SARS-CoV-2 native S1/S2 spike proteins was measured using the Diasorin (Liaison XL) assay, 4-6 months following a positive PCR. A mean antibody threshold of 15 Arbitrary unit per ml (AU/ml) was considered seropositive, with 94.4% positive agreement to plaque reduction neutralization tests (PRNT90) at a 1:40 ratio. Antibody titer was compared between children and adults. Results. 111 participants (52 adults and 59 children) were recruited from 50 separate families. Characteristic of participants and their clinical symptoms are described in Table 1. Among all participants, 76.3% children were SARS-CoV-2 seropositive vs. 51.9% of adults (p=0.007). Median antibody titer was significantly higher in children vs. adults (82.8 AU, [IQR: 18.4-130], vs 17.0 AU, [IQR: 6.8-77.8], p=0.006);findings were similar among SARS-CoV-2 PCR positive participants only. Overall, 13 participants were PCR positive but seronegative, 7 were PCR negative and seropositive, while 61 were both PCR positive and seropositive. Older participants and those with any comorbidity. Among the PCR positive group, the seropositive participants were younger (median age 31±17 vs 19±17 years, p=0.003) and more likely to have comorbidity (69% vs 29%, p=0.007). Conclusion. These results suggest that children have a stronger antibody response to SARS-CoV-2 infection than adults, and that older age and presence of comorbidity are associated with a less robust humoral response. Further work on the differences in response between children and adults may help elucidate mechanisms underlying the severity of disease.
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Introduction: Since the beginning of SARS-Cov-2 pandemic, children represent a small proportion of patients with an acute disease and present with mild symptoms or are either asymptomatic. However pediatric patients might present with late, post infectious, manifestations of COVID 19, namely Pediatric Inflammatory Multisystemic Syndrome temporally associated with COVID 19 (PIMS-TS). Objectives: We aim to describe the characteristics of pediatric patients with PIMS-TS hospitalised in Sainte Justine Hospital and report their evolution according to their treatment and care. Methods: Patients were recruited prospectively since April 2020. Patient were included if they were less than 18 years old, had at least 2 days of fever, had multisystemic involvement (at least 2 systems) and had a temporal association with COVID 19. This temporal association was defined as: positive reverse transcription (RT)-PCR or antibodies to SARS-Cov2, history of contact with a confirmed or suspected SARS-Cov 2 infected individual or symptom appearance during the pandemic. Patient were excluded if they had an alternative diagnosis that explained the symptoms. Patient were sub categorized into two categories depending on their clinical presentation: 1- Complete or incomplete Kawasaki disease (KD), following the American Heart Association Criteria;or 2- Toxic shock syndrome (TSS). Data were collected during the hospitalization and the follow up. Results: Between April 30th, 2020 and April 30th, 2021, 72 patients were included, 13 (18.1%) with complete KD, 40 (55.6%) with incomplete KD and 19 (26.4%) with TSS. There was more male in the complete KD group (69.2%) and more female in the TSS group (52.6%) but there was no significative difference between the two groups (p = 0.35). Patient with TSS presentation were significatively older than those with KD presentation (10.3 years vs 4.9 years, p < 0.01). Caucasian patients are the most represented ethnic group in the cohort (26.4 %) but Afro-American patient are over-represented in the TSS group (6/19 patients, 31.6%;p= 0.2). Gastro-intestinal symptoms were seen in 50.9% (27/53) and 94.7% (18/19) patients with KD and TSS respectively (p < 0.001). Patients in the TSS group had higher mean value of PCR (239.1 mg/L vs 143.9 mg/L;p< 0.001) and more frequent lymphopenia (89.5% vs 34%;p< 0.001) than those in KD group. Only 40/72 (55.6%) patients in the cohort had either a positive RT-PCR and/or positive antibodies to SARS-Cov-2 and/or a contact with confirmed or suspected infected individual. These proportion increase to 18/19 (94.7%) in the TSS group (p < 0.001). Twenty-three patients (31.9%) required ICU hospitalization including 17 on 19 patients in the TSS group (89.5%;p < 0.001). Cardiac involvement was the most frequent complication either as coronary aneurysm, (15/72 - 20.8%) mainly in patient with KD presentation or as cardiac dysfunction (24/72 - 33.3%), mainly in patient with TSS presentation. Patient received intravenous immunoglobulins (69/72 - 95.8%), steroids (49/72 - 68.1%), sometimes both (48/72 - 66.7%). Five patients (6.9%) required biotherapy: 1 with Enbrel and 4 with Anakinra. Patient received a treatment 6.6 days after the beginning of the symptoms. After 3 months, 4 patients (0.5%) had persistent coronary dilatation and 2 (0.3%) had mitral insufficiency. Conclusion: This cohort study enables a better description of PIMS clinical and biological presentation, which can sometimes be confusing. It also highlights the importance of fast and adequate diagnosis and treatment to avoid the risk of acute and chronic complications, especially cardiac complications.
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As the coronavirus disease 2019 (COVID-19) pandemic second wave is emerging, it is of the upmost importance to screen the population immunity in order to keep track of infected individuals. Consequently, immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high specificity and positive predictive values are needed to obtain an accurate epidemiological picture. As more data accumulate about the immune responses and the kinetics of neutralizing-antibody (nAb) production in SARS-CoV-2-infected individuals, new applications are forecast for serological assays such as nAb activity prediction in convalescent-phase plasma from recovered patients. This multicenter study, involving six hospital centers, determined the baseline clinical performances, reproducibility, and nAb level correlations of 10 commercially available immunoassays. In addition, three lateral-flow chromatography assays were evaluated, as these devices can be used in logistically challenged areas. All assays were evaluated using the same patient panels in duplicate, thus enabling accurate comparison of the tests. Seven immunoassays examined in this study were shown to have excellent specificity (98 to 100%) and good to excellent positive predictive values (82 to 100%) when used in a low (5%)-seroprevalence setting. We observed sensitivities as low as 74% and as high as 95% at ≥15 days after symptom onset. The determination of optimized cutoff values through receiver operating characteristic (ROC) curve analyses had a significant impact on the diagnostic resolution of several enzyme immunoassays by increasing the sensitivity significantly without a large trade-off in specificity. We found that spike-based immunoassays seem to be better correlates of nAb activity. Finally, the results reported here will add to the general knowledge of the interlaboratory reproducibility of clinical performance parameters of immunoassays and provide new evidence about nAb activity prediction.