An inflammatory syndrome in children and adolescents, believed to be linked to COVID-19, seems to be more common among children of African ancestry, finds a small study from researchers at Necker-Enfants Malades University Hospital, Assistance Publique – Hôpitaux de Paris (AP-HP), Université de Paris, Institut Pasteur, The Rockefeller Unversity and the Howard Hughes Medical Institute. The syndrome has been compared with Kawasaki disease, a rare condition which mainly affects children under five. Experts have said that it may be an "antibody mediated or delayed response" to covid-19 that happens several weeks after infection. Cases have also been seen in Italy, the UK and the US.
In this study, patients had characteristics that differ from those with classic Kawasaki disease. For example, an unusually high proportion had gastrointestinal symptoms (abdominal pain, often with vomiting and diarrhoea), unstable blood pressure, and inflammation of the heart muscle (myocarditis).
The researchers say further studies are needed, but these findings "should prompt high vigilance" among doctors, particularly in countries with a high proportion of children of African ancestry.
They describe 21 children and adolescents (average age 7.9 years) with features of Kawasaki disease who were admitted to a hospital in Paris between 27 April and 11 May 2020. Over half of the children (12; 57%) were of African ancestry. Twelve children presented with Kawasaki disease shock syndrome and 16 (76%) with myocarditis. Nineteen (90%) had evidence of recent COVID-19 infection.
All 21 patients had noticeable gastrointestinal symptoms during the early stage of illness and high levels of inflammatory markers in their bloodstream. Despite 17 patients (81%) needing intensive care support, all patients were discharged home by 15 May 2020, after an average of 8 days in hospital, with no serious complications.
The researchers point to some limitations, such as the small number of patients, and stress that this is an observational study, so can't establish a causal link with COVID-19 infection.
Nevertheless, they say this Kawasaki-like multi-system inflammatory syndrome seems to be more common in children of African ancestry, suggesting an effect of either social and living conditions or genetic susceptibility, and shows different clinical symptoms to classic Kawasaki disease.
"These clinical findings should prompt high vigilance among primary care and emergency doctors, and preparedness during the coronavirus disease 2019 pandemic in countries with a high proportion of children of African ancestry and high levels of community transmission," they conclude.
The researchers have added an important layer to the growing knowledge of this disorder, strengthening the connection between covid-19 infection and this condition, says Mary Beth Son at Boston Children's Hospital, in a linked editorial. She stresses that this condition is so far rare but potentially severe, and warrants surveillance as well as collaborative research.
It seems highly likely that more reports will appear from around the globe, she warns, but says the rapid release of publications such as this, "is the first step in this critical process."
Objectives: To describe the characteristics of children and adolescents affected by an outbreak of Kawasaki-like multisystem inflammatory syndrome and to evaluate a potential temporal association with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Design: Prospective observational study.
Setting: General paediatric department of a university hospital in Paris, France.
Participants: 21 children and adolescents (aged ≤18 years) with features of Kawasaki disease who were admitted to hospital between 27 April and 11 May 2020 and followed up until discharge by 15 May 2020.
Main outcome measures: The primary outcomes were clinical and biological data, imaging and echocardiographic findings, treatment, and outcomes. Nasopharyngeal swabs were prospectively tested for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR) and blood samples were tested for IgG antibodies to the virus.
Results: 21 children and adolescents (median age 7.9 (range 3.7-16.6) years) were admitted with features of Kawasaki disease over a 15 day period, with 12 (57%) of African ancestry. 12 (57%) presented with Kawasaki disease shock syndrome and 16 (76%) with myocarditis. 17 (81%) required intensive care support. All 21 patients had noticeable gastrointestinal symptoms during the early stage of illness and high levels of inflammatory markers. 19 (90%) had evidence of recent SARS-CoV-2 infection (positive RT-PCR result in 8/21, positive IgG antibody detection in 19/21). All 21 patients received intravenous immunoglobulin and 10 (48%) also received corticosteroids. The clinical outcome was favourable in all patients. Moderate coronary artery dilations were detected in 5 (24%) of the patients during hospital stay. By 15 May 2020, after 8 (5-17) days of hospital stay, all patients were discharged home.
Conclusions: The ongoing outbreak of Kawasaki-like multisystem inflammatory syndrome among children and adolescents in the Paris area might be related to SARS-CoV-2. In this study an unusually high proportion of the affected children and adolescents had gastrointestinal symptoms, Kawasaki disease shock syndrome, and were of African ancestry.
Julie Toubiana, Clément Poirault, Alice Corsia, Fanny Bajolle, Jacques Fourgeaud, François Angoulvant, Agathe Debray, Romain Basmaci, Elodie Salvador, Sandra Biscardi, Pierre Frange, Martin Chalumeau, Jean-Laurent Casanova, Jérémie F Cohen, Slimane Allal
BMJ linked editorial