Background There is paucity of information on rituximab-associated hypogammaglobulinemia (HGG) and its potential infectious consequences in children treated for idiopathic nephrotic syndrome (INS). Methods A survey was distributed by the European Society Pediatric Nephrology to its members. It addressed the screening and management practices of pediatric nephrology units for recognizing and treating RTX-associated HGG and its morbidity and mortality. Eighty-four centers which had treated an overall 1328 INS children with RTX responded. Results The majority of centers administered several courses of RTX and continued concomitant immunosuppressive therapy. Sixty-five percent of centers routinely screened children for HGG prior to RTX infusion, 59% during, and 52% following RTX treatment. Forty-seven percent had observed HGG prior to RTX administration, 61% during and 47% >9 months following treatment in 121, 210, and 128 subjects respectively. Thirty-three severe infections were reported among the cohort of 1328 RTX-treated subjects, of whom 3 children died. HGG had been recognized in 30/33 (80%) of them. Conclusions HGG in steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS) children is probably multifactorial and can be observed prior to RTX administration in children with SDNS/FRNS. Persistent HGG lasting >9 months from RTX infusion is not uncommon and may increase the risk of severe infections in this cohort. We advocate for the obligatory screening for HGG in children with SDNS/FRNS prior to, during, and following RTX treatment. Further research is necessary to identify risk factors for developing both HGG and severe infections before recommendations are made for its optimal management. Graphical abstract

Background Nursing homes (NHs) have been particularly affected by COVID-19. The aim of this study is to estimate the burden of COVID-19 and to investigate factors associated with mortality during the first epidemic wave in a large French NHs network. Methods An observational cross-sectional study was conducted in September-October 2020. 290 NHs were asked to complete an online questionnaire covering the first epidemic wave on facilities and resident characteristics, number of suspected/confirmed COVID-19 deaths, and preventive/control measures taken at the facility level. Data were crosschecked using routinely collected administrative data on the facilities. The statistical unit of the study was the NH. Overall COVID-19 mortality rate was estimated. Factors associated with COVID-19 mortality were investigated using a multivariable multinomial logistic regression. The outcome was classified in 3 categories: “no COVID-19 death in a given NH”, occurrence of an “episode of concern” (at least 10% of the residents died from COVID-19), occurrence of a “moderate episode” (deaths of COVID-19, less than 10% of the residents). Results Of the 192 (66%) participating NHs, 28 (15%) were classified as having an “episode of concern”. In the multinomial logistic regression, moderate epidemic magnitude in the NHs county (adjusted OR = 9.3; 95%CI=[2.6–33.3]), high number of healthcare and housekeeping staff (aOR = 3.7 [1.2–11.4]) and presence of an Alzheimer’s unit (aOR = 0.2 [0.07–0.7]) were significantly associated with an “episode of concern”. Conclusions We found a significant association between the occurrence of an “episode of concern” in a NH and some of its organizational characteristics and the epidemic magnitude in the area. These results can be used to improve the epidemic preparedness of NHs, particularly regarding the organization of NHs in small units with dedicated staff. Brief summary Factors associated with COVID-19 mortality and preventive measures taken in nursing homes in France during the first epidemic wave.