Multisystem inflammatory syndrome in children and SARS-CoV-2 variants: a two-year ambispective multicentric cohort study in Catalonia, Spain.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe disease temporarily related to SARS-CoV-2. We aimed to describe the epidemiological, clinical, and laboratory findings of all MIS-C cases diagnosed in children < 18 years old in Catalonia (Spain) to study their trend throughout the pandemic. This was a multicenter ambispective observational cohort study (April 2020-April 2022). Data were obtained from the COVID-19 Catalan surveillance system and from all hospitals in Catalonia. We analyzed MIS-C cases regarding SARS-CoV-2 variants for demographics, symptoms, severity, monthly MIS-C incidence, ratio between MIS-C and accumulated COVID-19 cases, and associated rate ratios (RR). Among 555,848 SARS-CoV-2 infections, 152 children were diagnosed with MIS-C. The monthly MIS-C incidence was 4.1 (95% CI: 3.4-4.8) per 1,000,000 people, and 273 (95% CI: 230-316) per 1,000,000 SARS-CoV-2 infections (i.e., one case per 3,700 SARS-CoV-2 infections). During the Omicron period, the MIS-C RR was 8.2 (95% CI: 5.7-11.7) per 1,000,000 SARS-CoV-2 infections, which was significantly lower (p < 0.001) than that for previous variant periods in all age groups. The median [IQR] age of MIS-C was 8 [4-11] years, 62.5% male, and 80.2% without comorbidities. Common symptoms were gastrointestinal findings (88.2%) and fever > 39 °C (81.6%); nearly 40% had an abnormal echocardiography, and 7% had coronary aneurysm. Clinical manifestations and laboratory data were not different throughout the variant periods (p > 0.05).  Conclusion: The RR between MIS-C cases and SARS-CoV-2 infections was significantly lower in the Omicron period for all age groups, including those not vaccinated, suggesting that the variant could be the main factor for this shift in the MISC trend. Regardless of variant type, the patients had similar phenotypes and severity throughout the pandemic. What is Known: • Before our study, only two publications investigated the incidence of MIS-C regarding SARS-CoV-2 variants in Europe, one from Southeast England and another from Denmark. What is New: • To our knowledge, this is the first study investigating MIS-C incidence in Southern Europe, with the ability to recruit all MIS-C cases in a determined area and analyze the rate ratio for MIS-C among SARS-CoV-2 infections throughout variant periods. • We found a lower rate ratio of MISC/infections with SARS-CoV-2 in the Omicron period for all age groups, including those not eligible for vaccination, suggesting that the variant could be the main factor for this shift in the MISC trend.

Cytomegalovirus and paediatric renal transplants: is this a current issue?

OBJECTIVE: An observational retrospective multicentre study of kidney transplants in paediatric patients was performed to evaluate the current situation of cytomegalovirus (CMV) in this population, before our participation in an international clinical trial of prophylaxis for 6 months. MATERIAL AND METHOD: Our study included 239 patients aged <19 years, from 5 Spanish centres between 2005-2009, with 1 year of follow-up. RESULTS: Pretransplant CMV serology was negative in 54% of recipients and 34.7% of donors. Sixty patients (25.1%) were considered at high risk (D+/R-) for CMV infection. Prophylaxis was used in 80.8% of recipients, including all high-risk patients, for an average time of 65.5 days. CMV viraemia occurred in 24.26% (58 cases among 239 patients), and disease in 6.7%. CMV infection was associated with serological status (D/R) (P<.001), positive serology of the donor (P<.001) and duration of prophylaxis <20 days (P<.05). There were no cases of patient or graft loss secondary to infection, nor resistance to treatment. CONCLUSIONS: The main preventative strategy against CMV in paediatric renal transplantation in our country is chemical prophylaxis (81%), with an incidence of infection and disease of 24% and 6.7%, respectively. There were no serious direct or indirect effects in the first year post-transplant. The incidence is mainly linked with serological D/R and positive donor status.