Association between the COVID-19 pandemic and pertussis in France using multiple nationwide data sources (preprint)

Background: Interventions to mitigate coronavirus disease 19 (COVID-19) pandemic may impact other respiratory diseases such as pertussis. We aimed to study the course of pertussis in France over an 8-year period and its association with COVID-19 mitigation strategies, using multiple nationwide data sources. Methods: We analyzed the number of French pertussis cases between 2013 and 2020, using the PCR test results from nationwide outpatient laboratories (Source 1) and the pediatric network of 41 hospitals (Source 2), and using the reports of an office-based pediatric national network (Source 3). We conducted a quasi-experimental interrupted time-series analysis, relying on negative binomial regression models. The models accounted for seasonality, longterm cycles, and secular trend, and included a binary variable for the first national lockdown (ordered on March 16, 2021). Results: We identified 19,039 cases of pertussis from the three data sources during the study period. There was a significant decrease of pertussis cases following the implementation of mitigation measures, with adjusted incidence rate ratios of 0.102 (95% CI 0.040-0.256) and 0.216 (95% CI 0.071-0.656) for Source 1 and Source 2, respectively. The association was confirmed in Source 3 (median of 1 [IQR 0-2] vs. 0 [IQR 0-0] pertussis cases per month before and after lockdown, respectively, p=0.0048). Conclusion: The drastic reduction of outpatient and hospitalized cases of pertussis strongly suggests an impact of COVID-19 mitigation measures and their consequences on pertussis epidemiology. Pertussis vaccination recommendations should be carefully followed, and disease monitoring should be continued to detect any resurgence after relaxation of mitigation measures.

Outbreak of Kawasaki disease in children during COVID-19 pandemic: a prospective observational study in Paris, France (preprint)

Background: Acute clinical manifestations of SARS-CoV-2 infection are less frequent and less severe in children than in adults. However, recent observations raised concerns about potential post-viral severe inflammatory reactions in children infected with SARS-CoV-2. Methods: We describe an outbreak of cases of Kawasaki disease (KD) admitted between April 27 and May 7, 2020, in the general paediatrics department of a university hospital in Paris, France. All children prospectively underwent nasopharyngeal swabs for SARS-CoV-2 RT-PCR, SARS-CoV-2 IgG serology testing, and echocardiography. The number of admissions for KD during the study period was compared to that observed since January 1, 2018, based on discharge codes, using Poisson regression. Results: A total of 17 children were admitted for KD over an 11-day period, in contrast with a mean of 1.0 case per 2-week period over 2018-2019 (Poisson incidence rate ratio: 13.2 [95% confidence interval: 7.3-24.1], p <0.001). Their median age was 7.5 (range, 3.7-16.6) years, and 59% of patients originated from sub-Saharan Africa or Caribbean islands. Eleven patients presented with KD shock syndrome (KDSS) requiring intensive care support, and 12 had myocarditis. All children had marked gastrointestinal symptoms at the early stage of illness and high levels of inflammatory markers. Fourteen patients (82%) had evidence of recent SARS-CoV-2 infection (positive RT-PCR 7/17, positive IgG antibody detection 14/16). All patients received immunoglobulins and some received corticosteroids (5/17). The clinical outcome was favourable in all patients. Moderate coronary artery dilations were detected in 5 cases (29%) during hospitalisation. Conclusions: The ongoing outbreak of KD in the Paris might be related to SARS-CoV2, and shows an unusually high proportion of children with gastrointestinal involvement, KDSS and African ancestry.

COVID-19-related mortality by age groups in Europe: A meta-analysis (preprint)

Background and ObjectivesTo date, more than 1,000,000 confirmed cases and 65,000 deaths due to coronavirus disease 2019 (COVID-19) have been reported globally. Early data have indicated that older patients are at higher risk of dying from COVID-19 than younger ones, but precise international estimates of the age-breakdown of COVID-19-related deaths are lacking. Materials and MethodsWe evaluated the distribution of COVID-19-related fatalities by age groups in Europe. On April 6, 2020, we systematically reviewed COVID-19-related mortality data from 32 European countries (European Union/European Economic Area and the United Kingdom). We collated official reports provided by local Public Health or Ministry of Health websites. We included countries if they provided data regarding more than 10 COVID-19-related deaths stratified by age according to pre-specified groups (i.e., < 40, 40-69, [≥] 70 years). We used random-effects meta-analysis to estimate the proportion of age groups among all COVID-19-related fatalities. ResultsThirteen European countries were included in the review, for a total of 31,864 COVID-19-related deaths (range: 27-14,381 per country). In the main meta-analysis (including data from Germany, Hungary, Italy, Netherlands, Portugal, Spain, Switzerland; 21,522 COVID-19-related fatalities), the summary proportions of persons < 40, 40-69, and [≥] 70 years of age among all COVID-19-related deaths were 0.1% (0.0-0.2%; I2 24%), 12.8% (10.3-15.6%; I2 94%), and 84.8% (81.3-88.1%; I2 96%), respectively. ConclusionsPeople under 40 years of age represent a small fraction of the total number of COVID-19-related deaths in Europe. These results may help health authorities respond to public concerns and guide future physical distancing and mitigation strategies.