Exploring the Infectious Contribution to Intussusception Causality Using the Effects of COVID-19 Lockdowns in Australia: An Ecological Study.

BACKGROUND: Intussusception is the primary cause of acute bowel obstruction in infants. The majority of cases <2 years of age are classed as idiopathic, with viral infection implicated as one of the causes. Coronavirus disease 2019 (COVID-19) public health measures led to significant decreases in communicable disease prevalence. During these times, reductions in intussusception frequency were greater than would be expected with our previous understanding of its infectious etiology. METHODS: We conducted a retrospective, multistate, ecological study over a 12-year period. Monthly case numbers of "intussusception"-coded admissions (code K56.1; International Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification) were acquired from state-wide admissions data sets from New South Wales, Victoria, and Queensland, representing 77.62% of the eligible Australian population. These counts within differing jurisdictional lockdowns were compared with non-lockdown periods in order to investigate a correlation between intussusception frequency and lockdown periods. RESULTS: We found a negative association between intussusception frequency and lockdown periods in both eligible states. The largest reductions were seen in the <2-year age groups, with Victoria experiencing a 62.7% reduction (rate ratio, 0.37; P < .001) and New South Wales a 40.1% reduction (0.599; P = .006) during lockdown times. Controls for variations in lockdown restrictions between both regional and metropolitan areas also showed expected decreases. CONCLUSIONS: Our ecological study demonstrates significant decreases in the frequency of pediatric intussusception admissions during the COVID-19 lockdown periods. The unexpected magnitude of the reductions suggests that the true proportion of infectious disease-caused idiopathic intussusception is greatly underestimated.

Snotwatch: an ecological analysis of the relationship between febrile seizures and respiratory virus activity.

BACKGROUND: Febrile seizures are the commonest type of seizure in occurring in the first few years of life, mostly affecting children aged six months to five years old. While largely benign, the incidence of each febrile seizure increases the risk of recurrence, afebrile seizures and epilepsy. Viruses are the most frequent cause of febrile illnesses in which a febrile seizure occurs. Febrile seizure presentation patterns appear to follow a seasonal trend. AIMS: To identify patterns of febrile seizure incidence across different seasons with specific viral activity, and to establish a framework for analysing virus circulation data with common illnesses within a shared region and population. SETTING: Our study was a study of febrile seizure presentations in Victoria, Australia and respiratory virus detection. PARTICIPANTS: We obtained independent datasets of emergency department febrile seizure presentations at Monash Health and all respiratory multiplex PCR tests performed at Monash Health from January 2010-December 2019 to observe common trends in virus circulation and febrile seizure incidence. STUDY DESIGN: Trends were studied temporally through mixed effects Poisson regression analysis of the monthly incidence of febrile seizures and the rate of positive PCR tests. Peak viral seasons (95th centile incidence) were compared to median viral circulation (50th centile incidence) to calculate peak season risk ratios. RESULTS: We found a 1.75-2.06 annual risk ratio of febrile seizure incidence in June-September. Temporal analysis of our data showed this peak in febrile seizures was attributable to circulating viruses in this season, and virus modelling showed correlation with increased rates of positive Influenza A (1.48 peak season risk ratio), Influenza B (1.31 peak season risk ratio), Human metapneumovirus (1.19 peak season risk ratio) and Respiratory Syncytial Virus (1.53 peak season risk ratio) on PCR testing. CONCLUSION: Our ecological study statistically demonstrates the recognised winter peak in febrile seizure incidence and ascribes the seasonal relationship to several viral infections which affect the community, including a novel association with Human metapneumovirus.

Kawasaki Disease and Respiratory Viruses: Ecological Spatiotemporal Analysis.

Background: Kawasaki disease is an uncommon vasculitis affecting young children. Its etiology is not completely understood, although infections have been frequently postulated as the triggers. Respiratory viruses, specifically, have often been implicated as causative agents for Kawasaki disease presentations. Objective: We aimed to conduct an ecological spatiotemporal analysis to determine whether Kawasaki disease incidence was related to community respiratory virus circulation in a shared region and population, and to describe viral associations before and during the COVID-19 pandemic. Methods: We obtained independent statewide data sets of hospital admissions of Kawasaki disease and respiratory multiplex polymerase chain reaction tests performed at two large hospital networks in Victoria, Australia, from July 2011 to November 2021. We studied spatiotemporal relationships by negative binomial regression analysis of the monthly incidence of Kawasaki disease and the rate of positive respiratory polymerase chain reaction tests in different regions of Victoria. Peak viral seasons (95th percentile incidence) were compared to median viral circulation (50th percentile incidence) to calculate peak season increased rate ratios. Results: While no seasonal trend in Kawasaki disease incidence was identified throughout the study period, we found a 1.52 (99% CI 1.27-1.82) and a 1.43 (99% CI 1.17-1.73) increased rate ratio of Kawasaki disease presentations in association with human metapneumovirus and respiratory syncytial virus circulation, respectively, before the COVID-19 pandemic. No respiratory viral associations with Kawasaki disease were observed during the COVID-19 pandemic. Conclusions: Our large ecological analysis demonstrates novel spatiotemporal relationships between human metapneumovirus and respiratory syncytial virus circulation with Kawasaki disease. The disappearance of these associations in the COVID-19 pandemic may reflect the reduced circulation of non-SARS-CoV-2 viruses during this period, supporting the prepandemic associations identified in this study. The roles of human metapneumovirus and respiratory syncytial virus in Kawasaki disease etiology warrant further investigation.

Pediatric Hepatitis and Respiratory Viruses: A Spatiotemporal Ecologic Analysis.

INTRODUCTION: Beginning in early 2022, clusters of severe pediatric hepatitis were reported in Europe and the United States. To date, no cause has been identified although human adenovirus 41 has been proposed in a proportion of cases. We examined population data >11 years for hepatitis clusters in Victoria, Australia, and whether any were spatiotemporally associated with community transmission of common respiratory viruses. METHODS: We used SaTScan to analyze for clusters of pediatric hepatitis and respiratory adenoviruses in Victoria. Negative binomial regression analysis was performed to determine any associations between hepatitis and respiratory viruses across Victoria between July 1, 2011, and June 30, 2022. RESULTS: A number of positive associations were observed in Victoria between pediatric hepatitis clusters and respiratory viruses in our spatiotemporal analysis. A positive association was not found with respiratory adenoviruses or SARS-CoV-2. Increased hepatitis clusters were observed in 2021 and 2022 as noted internationally. CONCLUSION: The current hepatitis outbreak is novel and, although respiratory viruses are broadly associated with hepatitis, SARS-CoV-2 and respiratory adenoviruses are unlikely to be related.

Snotwatch COVID-toes: An ecological study of chilblains and COVID-19 diagnoses in Victoria, Australia.

The COVID-19 pandemic has caused widespread illness with varying clinical manifestations. One less-commonly-reported presentation of COVID-19 infection is chilblain-like lesions. We conducted an ecological analysis of chilblain presentations in comparison with confirmed and suspected COVID-19 infections in a primary care setting to establish that a relationship exists between the two. Our study collated data from three Primary Health Networks across Victoria, Australia, from 2017-2021, to understand patterns of chilblain presentations prior to and throughout the pandemic. Using a zero-inflated negative binomial regression analysis, we estimated the relationship between local minimum temperature, COVID-19 infections and the frequency of chilblain presentations. We found a 5.72 risk ratio of chilblain incidence in relation to COVID-19 infections and a 3.23 risk ratio associated with suspected COVID-19 infections. COVID-19 infections were also more strongly associated with chilblain presentations in 0-16-year-olds throughout the pandemic in Victoria. Our study statistically suggests that chilblains are significantly associated with COVID-19 infections in a primary care setting. This has major implications for clinicians aiming to diagnose COVID-19 infections or determine the cause of a presentation of chilblains. Additionally, we demonstrate the utility of large-scale primary care data in identifying an uncommon manifestation of COVID-19 infections, which will be significantly beneficial to treating physicians.

A Review of Febrile Seizures: Recent Advances in Understanding of Febrile Seizure Pathophysiology and Commonly Implicated Viral Triggers.

Febrile seizures are one of the commonest presentations in young children, with a 2-5% incidence in Western countries. Though they are generally benign, with rare long-term sequelae, there is much to be learned about their pathophysiology and risk factors. Febrile seizures are propagated by a variety of genetic and environmental factors, including viruses and vaccines. These factors must be taken into consideration by a clinician aiming to assess, diagnose and treat a child presenting with fevers and seizures, as well as to explain the sequelae of the febrile seizures to the concerned parents of the child. Our article provides an overview of this common childhood condition, outlining both the underlying mechanisms and the appropriate clinical approach to a child presenting with febrile seizures.