Saliva for molecular detection of SARS-CoV-2 in pre-school and school-age children.

SARS-CoV-2 diagnosis is a cornerstone for the management of coronavirus disease 2019 (COVID-19). Numerous studies have assessed saliva performance over nasopharyngeal sampling (NPS), but data in young children are still rare. We explored saliva performance for SARS-CoV-2 detection by RT-PCR according to the time interval from initial symptoms or patient serological status. We collected 509 NPS and saliva paired samples at initial diagnosis from 166 children under 12 years of age (including 57 children under 6), 106 between 12 and 17, and 237 adults. In children under 12, overall detection rate for SARS-CoV-2 was comparable in saliva and NPS, with an overall agreement of 89.8%. Saliva sensitivity was significantly lower than that of NPS (77.1% compared to 95.8%) in pre-school and school-age children but regained 96% when considering seronegative children only. This pattern was also observed to a lesser degree in adolescents but not in adults. Sensitivity of saliva was independent of symptoms, in contrary to NPS, whose sensitivity decreased significantly in asymptomatic subjects. Performance of saliva is excellent in children under 12 at early stages of infection. This reinforces saliva as a collection method for early and unbiased SARS-CoV-2 detection and a less invasive alternative for young children.

1-Year Follow-Up Data of Arterial Abnormalities Identified in Kidneys Transplanted into Children During the First Covid-19 Pandemic Wave

BACKGROUND AND AIMS Graft artery stenosis can have a significant short- and long-term negative impact on kidney graft function. We previously reported an unusual number of graft-arterial anomalies following kidney transplantation (KTx) in children during the first coronavirus disease (COVID-19) pandemic wave (Berteloot et al.) [1]. We report herein the 1-year follow-up of these patients. METHOD In this retrospective study, we included all children who received a KTx at our centre from February to July 2020. We compared their outcome to that of paediatric recipients who were transplanted at our centre from 2015 to 2019 and presented an allograft vascular complication (‘Historic’ group) by querying our local data warehouse. RESULTS Among the 9 children who received a KTx at our centre between February and July 2020 [8 boys, median age 10 years (3–17)], 8 presented Doppler features suggesting arterial stenosis, with an unusual extensive pattern (Figure 1) after a median delay of 13 days (8–113). For comparison, persistent spectral Doppler arterial anomalies were observed in only 5% of children following KTx at our centre over the previous 5-year period and were all focal anastomotic stenoses. In addition, five children had lymphoceles, which required surgical management as compared to only one patient in the 5 previous years (1%).  We retrospectively diagnosed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-20 infection in 6/8 children with arterial stenosis on serologies performed at D0, including one boy with a history of positive real time reverse transcription-polymerase chain reaction (RT-PCR) 120 days before KTx. None of the patients had reported any symptom suggestive of COVID-19. The remaining two patients had received a graft from an asymptomatic deceased adolescent donor with a positive serology at D0. These data led us to suspect immune post-viral graft vasculitis, triggered by SARS-CoV-2. At 1-year post-transplantation, the outcome was favourable in the 8 isolated KTx recipients. A total of 4/8 children had normal blood pressure and 4 had controlled high blood pressure on mono or bi-therapy. Doppler anomalies had resolved in 5/8 and persisted in 3/8 with a trend for improvement of peak systolic velocities and no severe consequences on kidney function and histology. Indeed, the median glomerular filtration rate (GFR) was 91 mL/min/1.73 m² (65–129), with unspecific and mild lesions on 4/8 protocol kidney biopsies (IFTA 1 or Cpt 1). One liver-kidney graft recipient had persistent hypertension and diffuse irregular inflammatory parietal thickening of the whole vascular graft associated with a parietal thrombus upstream of the birth of the two hepatic arteries (Figure 2);treated with anti-aggregation and prednisone 10 mg/d. CONCLUSION Our case series suggests a risk of post-viral kidney graft vasculitis in children with recent SARS-CoV-2 infection in the recipient or donor. Pre-transplant vaccination against COVID-19 is mandatory in children > 5 years and their kidney donor candidates at our centre. We also strongly recommend vaccination of all people aged > 5 years in the household.FIGURE 1: Angio-CT scan of a KTx recipient showing an atypical extensive stenosis, with a diffuse, thin and irregular appearance of the graft artery.FIGURE 2: Angio-CT scan of the liver-kidney graft recipient showing an atypical diffuse irregular inflammatory parietal thickening of the whole vascular graft associated with a parietal thrombus upstream of the birth of the two hepatic arteries.

Arterial abnormalities identified in kidneys transplanted into children during the COVID-19 pandemic.

Graft artery stenosis can have a significant short- and long-term negative impact on renal graft function. From the beginning of the COVID-19 pandemic, we noticed an unusual number of graft arterial anomalies following kidney transplant (KTx) in children. Nine children received a KTx at our center between February and July 2020, eight boys and one girl, of median age of 10 years. Seven presented Doppler features suggesting arterial stenosis, with an unusual extensive pattern. For comparison, over the previous 5-year period, persistent spectral Doppler arterial anomalies (focal anastomotic stenoses) following KTx were seen in 5% of children at our center. We retrospectively evidenced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in five of seven children with arterial stenosis. The remaining two patients had received a graft from a deceased adolescent donor with a positive serology at D0. These data led us to suspect immune postviral graft vasculitis, triggered by SARS-CoV-2. Because the diagnosis of COVID-19 is challenging in children, we recommend pretransplant monitoring of graft recipients and their parents by monthly RT-PCR and serology. We suggest balancing the risk of postviral graft vasculitis against the risk of prolonged dialysis when considering transplantation in a child during the pandemic.