Henoch-Schönlein purpura incidence fell, rose with COVID-19 protective measures
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Key takeaways:
- The incidence of Henoch-Schönlein purpura significantly decreased with the implementation of COVID-19 protective measures.
- Pneumococcus and group A streptococcus had “a key role” in pediatric HSP epidemiology.
Incidence of Henoch-Schönlein purpura waned and waxed significantly with the implementation and relaxation of non-pharmaceutical interventions against COVID-19, according to data published in JAMA Network Open.
The study additionally suggests that approximately 60% of Henoch-Schönlein purpura (HSP) incidence is associated with pneumococcus and group A streptococcus. HSP is the most common type of vasculitis in children, according to the researchers.
“Several seasonal viruses and bacterial infections have been associated with childhood HSP,” Arthur Felix, MD, of Robert-Debré University Hospital, in Paris, and colleagues wrote. “However, differentiating the specific associations of these pathogens with the onset of HSP remains a challenge due to their overlapping seasonal patterns.
“The SARS-CoV-2 pandemic led to a marked reduction in the circulation of pathogens in the pediatric population as a result of international nonpharmaceutical interventions (NPIs), such as social distancing and masking,” they added. “Subsequently, after these NPIs were relaxed in the spring of 2021, unusual outbreaks of viral and bacterial pathogens were reported in France and other countries.”
According to Felix and colleagues, this period represented a “unique opportunity” to study the role individual seasonal pathogens play in HSP. To accomplish this, the researchers conducted a population-based interrupted time-series analysis of data from the French Medicalization of Information Systems Program, a hospital-based national surveillance system.
The study included all 9,790 children in France aged younger than 18 years hospitalized for HSP between January 2015 and March 2023 (median age, 5 years), as well as all 757,110 children hospitalized with infections due to any of 14 common seasonal pathogens (median age, 0.7 years).
The main outcomes were monthly incidence of HSP per 100,000 children, calculated using a quasi-Poisson regression model, and, during the same period, the estimated percentage of HSP potentially associated with the seasonal pathogens.
According to the researchers, HSP incidence decreased significantly after NPIs against COVID-19 were implemented in March 2020 (–53.6%; 95% CI, –66.6% to –40.6%), and then increased significantly after their relaxation in April 2021 (37.2%; 95% CI, 28%-46.3%).
Meanwhile, the multivariate quasi-Poisson regression model demonstrated that the pathogens potentially associated with the greatest percentages of HSP incidence were Streptococcus pneumoniae (37.3%; 95% CI, 22.3%-52.3%), Streptococcus pyogenes (25.6% 95% CI, 16.7%-34.4%) and human rhino enterovirus (17.1% 95% CI, 3.8%-30.4%).
“In addition to confirming the association between infections and HSP epidemiology, this epidemiologic scenario suggested a key role of pneumococcus and group A streptococcus in pediatric HSP epidemiology,” Felix and colleagues wrote. “Further studies are needed to assess the potential effect of preventing streptococcal infections on reducing the incidence of HSP.”