When preexisting asthma and influenza collide – vaccination is critical
Published: November 12, 2022
Children with asthma are at increased risk for respiratory illness necessitating admission to a pediatric intensive care unit (PICU) due to infection with influenza viruses. Vaccination against influenza decreases this risk.
In this issue of The Journal of Allergy and Clinical Immunology: In Practice, Maddux, Grunwell, and colleagues examined hospital treatments and post-discharge respiratory sequelae in children who were admitted to a pediatric intensive care or high-acuity unit between November 2019 and April 2020 for influenza as part of the 17-site Pediatric Intensive Care Influenza Network Investigators (PICFLU) network. The authors hypothesized that children with pre-existing asthma were at higher risk of persistent respiratory impairments after discharge.
This study evaluated 165 children with critical influenza including 56 (34%) with preexisting asthma. In this cohort, influenza vaccination rates were low (~40%) amongst children with and without pre-existing asthma. During hospitalization, children with asthma more commonly received medicines used to treat asthma exacerbations (77%) compared to those without an asthma history (28%). Other hospitalization characteristics were similar between children with and without asthma: approximately one in four required ventilator support and similar average length of PICU (~2.5 days) and hospital stays (~5 days). Survey data were collected approximately 3 months after discharge from 46 of 55 (84%) patients with pre-existing asthma and 90 of 107 (84%) without pre-existing asthma. After discharge, children with pre-existing asthma reported asthma symptoms more frequently than those without asthma (78% vs. 3%) and were more likely to visit a respiratory specialist for their symptoms (52% vs. 20%). A similar proportion of children with versus without asthma had an emergency department visit (4.3% vs. 6.6%) or hospital readmission (8.6% vs. 3.3%) for a respiratory condition. Notably, one in ten children without preexisting asthma were newly diagnosed with asthma after hospitalization.
These results suggest that patients with and without pre-existing asthma had similar manifestations of severe illness including need for invasive ventilation. After discharge, respiratory symptoms were common, particularly amongst those with pre-existing asthma, and less than half of the cohort was evaluated by a respiratory specialist. Additionally, less than half were vaccinated against influenza. Advocating for infection prevention through vaccination and treatment of post-discharge morbidities may mitigate morbidities resulting from critical illness caused by influenza, particularly in children with pre-existing asthma.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.