The unexpected decrease of Kawasaki syndrome during the second COVID-19 wave: the report from the COVASAKI survey

Introduction: During the first pandemic wave, Tuscany reported the fifth Italian highest number of COVID-19 cases in Italy even if this prevalence was lower if compared to other high-prevalence regions in the North of Italy. From September 2020, Tuscany situation has deeply changed with a significant increase of SARS CoV-2 positive cases, currently standing almost 234,000. Objectives: The Pediatric Tuscany Network continued the COVASAKI survey with the aim to track children who received a Kawasaki Syndrome (KS) or Multisystem Infalmmatory syndrome (MIS-C) diagnosis during the second vawe of COVID-19 pandemic. Methods: We retrospectively collected demographics, clinical findings, treatment and outcome of KS and MIS-C children between November 1st, 2020 to April 30th,2021 and compared the number of KS cases during this period to the number of reported KS children in the first pandemic vawe and in the previous five years in the same region. Results: 14 MIS-C children were admitted to 5 Paediatric Units (incidence 2.3/month), 10 boys and 4 girls (mean age of 9.6 years [IQR] 8.8-12). 11/14 patients required intensive care unit admission: 10 needed amines and 3 underwent mechanical ventilation. Echocardiography revealed a reduced left ventricular ejection fraction in 8/14. A diffuse coronary artery ectasia was found in 1. All children completely recovered with a timely immunomodulatory treatment with intravenous immunoglobulins, steroids and, in case of severe cardiac involvement, anakinra. Nasopharyngeal swabs and serological test for SARS CoV-2 resulted positive in 5/13 and 14/14 respectively. The MIS-C incidence rate, adjusted for the 5,170 children hospitalized, resulted 0.27% and represented the 13.9 % of paediatric COVID 19- related hospital admissions in Tuscany. Conversely, the number of observed KS significantly reduced comparing to the first six months of COVASAKI survey: 3 cases, 0.5 incidence/month vs 11 cases, 1.8 incidence/ month (p <0.03, RR 0.27, 95% CI 0.06 to 0.92). Comparing the 2.7 incidence/month of the 165 diagnosed KS from 1st January 2015 to 31th January 2020, a statistically significant difference has been detected (p <0.0005, RR 0.24, 95% CI 0.07 to 0.59). The same result has been found limiting the analysis to the 92 children with KS diagnosed during the same corresponding 6 months of the last 5 years: 3.0 versus 0.7 incidence/month (p <0.0002, RR 0.21, 95% CI 0.06 to 0.53). Conclusion: Our results seem in accordance with the hypothesis of an infectious trigger in KS pathogenesis. The stay-home imposed by pandemic and the extensive adoption of barrier protection devices have concomitantly reduced the incidence of respiratory infections among general and paediatric population. At this regard, the massive drop in the number of influenza and Syncytial Virus infections during the winter months results emblematic. From this point of view, it could be hypothesized that, in contrast to what had been previously reported in the early stages of its outbreak, the SARS CoV-2 pandemic could lead to a reduction rather than a substantial increase in the number of KS cases. Although indirectly, the behavioural measures adopted to contain the contagion or maybe further mechanisms not yet identified might be the reason.

The recommended lifetime immunization schedule from the board of vaccination calendar for life in Italy: A continuing example of impact on public health policies.

The Vaccination Calendar for Life is an alliance of scientific and professional societies of public health physicians, paediatricians and general practitioners in Italy which provides a periodical update on the ideal, scientifically driven vaccination calendar throughout lifetime. Since 2012, the Lifetime Immunization Schedule has represented a benchmark for Regional and National Authorities to set up the updated list of vaccines provided actively and free of charge to infants, children, adolescents, adults and the elderly by inclusion in the Triennial National Vaccination Plan (TNVP), and in the Essential Levels of Care (LEA). The impact of the different editions of the Lifetime Immunization Schedule on the TNVP was deep, representing the inspiring source for the present vaccination policy. The 2019 edition called for more attention to pregnant women immunization; risk groups vaccination; uniform high coverage with the MMRV vaccine; extension of Meningococcal B vaccination also at adolescent age; use of quadrivalent conjugate meningococcal vaccine also at 1 year of life; progressive decrease of the age of free-of-charge offer of influenza to ≥ 60 and then to ≥ 50 year-old population; implementation of flu immunization ages 6 months-6 years; HPV vaccination also offered to 25-year old women at the time of the first screening (gender neutral immunization already offered); sequential PCV13-PPV23 pneumococcal vaccination in 65 year-old subjects; increased coverage with rotavirus vaccine in infants and zoster vaccine in the elderly.

Maintain and increase vaccination coverage in children, adolescents, adults and elderly people: Let's avoid adding epidemics to the pandemic: Appeal from the Board of the Vaccination Calendar for Life in Italy: Maintain and increase coverage also by re-organizing vaccination services and reassuring the population.

The Board of the Vaccination Calendar for Life (Bonanni et al., 2014, 2017) [1,2]), a coalition of four major scientific and professional societies of public health physicians, pediatricians and general practitioners in Italy, made an appeal to health authorities in order to sustain vaccination in COVID-19 times. The five pillars to maintain and increase vaccination coverage at all ages are described as follows: 1) Guarantee paediatric vaccination coverage to all newborns and paediatric boosters and adolescent immunizations, not interrupting active calls and scheduled sessions. 2) Re-organise the way paediatric and adolescent vaccinations are offered. 3) Set-up recovery programs for vaccinations not carried out after the start of the COVID-19 emergency. 4) Provide the preparation of tenders for the supply of flu vaccines with suitable quantities to increase coverage in all Regions and Autonomous Provinces with extreme urgency. 5) Prepare plans to increase coverage for influenza, pneumococcal, tetanus diphtheria and shingles. The Board of the Calendar for Life appeals to the National and Local Health Authorities for a strong and coordinated commitment in favor of the widest offer and acceptance of vaccinations, whose vital importance for collective health is now even more evident to all, in order to avoid that delays in the necessary initiatives should add damage from other epidemics to those suffered by our population due to the COVID-19 pandemic.