Asthma Drug Prescriptions in Norwegian Children Plunged and Surged Through the Pandemic

Inhaled corticosteroids are the cornerstone of modern asthma therapy, yet the way doctors prescribe them to the youngest children has long puzzled pediatric researchers. Preschoolers receive these anti-inflammatory inhalers at rates far higher than older children, a gap that cannot be explained by how common asthma actually is in each age group. A new nationwide study from Norway has now tracked how prescriptions of inhaled corticosteroids in children shifted before, during, and after the COVID-19 pandemic, and the results reveal a strikingly sensitive barometer of both viral circulation and prescribing habits. Drawing on more than a decade of national dispensing data, the researchers show that the pandemic did not simply suppress prescriptions across the board. Instead, it reshaped them in age-specific waves, with a dramatic collapse in the youngest children, a delayed surge in school-age groups, and persistent regional differences that survived every phase of the pandemic.

The study, published in BMC Pediatrics by Knut Øymar and Ingvild Bruun Mikalsen of Stavanger University Hospital and the University of Bergen, together with Ketil Størdal of the University of Oslo and Oslo University Hospital and statistician Ingvild Dalen of Stavanger University Hospital, exploited one of the richest data resources available anywhere in the world for this kind of question. The Norwegian Prescribed Drug Registry, maintained by the Norwegian Institute of Public Health, records every prescription drug dispensed to Norwegian residents, linked to anonymized demographic information. The team extracted annual counts of children aged zero to fourteen years with at least one dispensed inhaled corticosteroid prescription for every year from 2013 through 2025, and then added monthly resolution for the critical pandemic window from 2019 to 2022. Crucially, the data were stratified by three age bands, zero to four years, five to nine years, and ten to fourteen years, as well as by sex and by county, allowing the researchers to dissect trends with unusual granularity.

To convert raw dispensing counts into comparable rates, the investigators calculated prescriptions per 1000 children in each stratum and modeled the time trends using Poisson regression, the standard statistical framework for count data such as disease events or prescriptions in a defined population. This approach let them estimate whether year-to-year changes were statistically meaningful rather than random noise, and to quantify the size of shifts such as the pandemic-era decline in the youngest group. Because the registry captures dispensed drugs rather than merely written prescriptions, the data reflect what families actually collected from pharmacies, a stronger signal of real-world treatment than prescription records alone. The researchers also emphasize that the database is fully anonymized, that no personally identifiable information was available to them, and that the analysis of anonymous statistics did not require ethics committee approval under Norwegian regulations.

The headline finding concerns the preschool children, the group with the highest prescription rates and the greatest volatility. Before the pandemic, rates in children aged zero to four years were already drifting gently downward. When COVID-19 arrived in Norway in early 2020, that gentle decline turned into a sharp drop: prescription rates fell by a further 19 percent in 2020 compared with the pre-pandemic trajectory. The most plausible explanation, the authors suggest, is the near-disappearance of respiratory infections during the strict infection-control period. Viral wheezing illnesses in toddlers are frequently mislabeled and treated as asthma, so when the viruses vanished, so did much of the trigger for prescribing inhaled steroids. By 2022, however, rates had climbed back above pre-pandemic levels, a rebound that coincided with the intense wave of respiratory syncytial virus and other infections that swept through young children as immunity debts were repaid. Since that peak, rates have declined again through 2025, hinting at a slow correction back toward baseline.

The monthly data add a vivid, almost cinematic dimension to this story. At the onset of the pandemic in March 2020, prescriptions in young children spiked sharply, likely reflecting a last surge of consultations before lockdowns took hold and families avoided health services. Rates then fell to markedly low levels for the remainder of the period when infections were suppressed. When society reopened and viruses returned, the monthly curves revealed pronounced winter peaks in subsequent seasons, echoing the seasonal rhythm of respiratory infections. This seasonal signature is important because it reinforces the interpretation that a substantial share of inhaled corticosteroid prescribing in preschoolers tracks infection-related respiratory symptoms rather than confirmed chronic asthma. In other words, the pandemic functioned as an unplanned natural experiment: remove the viruses, and a large fraction of the prescribing pressure evaporates.

The older age groups told a different and arguably more surprising story. Among children aged five to nine years, prescription rates were essentially stable through the pandemic itself, but then rose significantly from 2021 to 2024. Children aged ten to fourteen years also showed stable rates overall, with a moderate increase beginning from 2022. These delayed increases contrast sharply with the collapse-and-rebound pattern seen in toddlers, and they suggest that the pandemic’s aftermath affected school-age children in the opposite direction. One candidate explanation is the wave of asthma diagnoses and symptom flare-ups that followed the return of viral circulation and, in some countries, a documented rise in asthma presentations after restrictions eased. Another possibility raised by the authors is improved adherence to clinical guidelines, with doctors better initiating controller therapy in school-age children who genuinely need it. The data cannot separate these mechanisms definitively, but the timing and age pattern provide important clues for clinicians and guideline developers.

Perhaps the most sobering finding is geographic. Prescription rates varied substantially between Norwegian counties, and the variation was greatest precisely where prescribing was most volatile: among children aged zero to four years, rates differed more than threefold between counties. For older children the regional spread was narrower but still evident. Remarkably, these regional differences were largely consistent over time, persisting through the pre-pandemic years, the pandemic disruption, and the post-pandemic rebound. Such stability suggests that the differences are not driven by transient outbreaks or random fluctuation but by durable local factors: differing diagnostic traditions, local guidelines and referral pathways, the composition of primary care, or genuine regional variation in disease burden and environmental exposures. A threefold difference in dispensed steroid prescriptions between regions of a single country with a unified health system is difficult to reconcile with uniform disease epidemiology alone, and it strengthens the authors’ suspicion that some prescribing in young children reflects practice variation rather than clinical necessity.

Taken together, the findings point toward a conclusion with real clinical weight: inhaled corticosteroids may be overprescribed for infection-related respiratory symptoms in young children. Inhaled corticosteroids are the basic, guideline-recommended treatment for asthma, and when used appropriately they transform outcomes for children with persistent disease. But in toddlers with recurrent viral wheeze, the evidence for maintenance steroid therapy is weaker, symptoms often remit as the child grows, and unnecessary exposure carries avoidable costs, both systemic side effects in growing bodies and the burden of daily medication for families. The pandemic-era collapse in prescriptions among zero-to-four-year-olds, followed by a rebound tied to viral resurgence, is exactly the pattern one would expect if a meaningful share of that prescribing was responding to transient infections rather than stable asthma. At the same time, the authors are careful to note the more optimistic reading of the recent trends: the rising rates in school-age children and the post-2022 dynamics may partly reflect better guideline adherence, meaning some of the change could represent improved care rather than excess treatment.

The study also demonstrates the power of nationwide dispensing registries to expose prescribing epidemiology that no clinical trial could capture. By spanning thirteen years, three age bands, monthly resolution during the pandemic, and every Norwegian county, the analysis turned an ordinary medication into a probe of how infections, health system behavior, and local practice interact. For pediatricians, the practical message is to scrutinize the indication before starting maintenance inhaled steroids in preschool children, particularly during winter infection seasons and in regions with historically high prescribing rates. For policymakers, the persistent regional disparities identify a concrete target for harmonizing guidelines and audit practices. And for researchers, the pandemic has left behind an invaluable dataset: a multi-year record of what happened to pediatric asthma treatment when the viruses that drive so much of childhood respiratory morbidity were suddenly switched off and then switched back on. As Norway’s prescription rates continue to evolve through 2025 and beyond, this study provides the baseline against which the long-term legacy of COVID-19 on children’s respiratory care will be measured.

Subject of Research: Time trends and regional variation in inhaled corticosteroid prescriptions to Norwegian children before, during, and after the COVID-19 pandemic

Article Title: Prescription of inhaled corticosteroid in children before, during, and after the COVID-19 pandemic: time trends and regional differences in Norway

Article References: Øymar, K., Størdal, K., Dalen, I., & Mikalsen, I. B. (2026). Prescription of inhaled corticosteroid in children before, during, and after the COVID-19 pandemic: time trends and regional differences in Norway. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07791-6

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07791-6

Keywords: inhaled corticosteroids, asthma, children, preschool children, COVID-19 pandemic, respiratory infections, Norwegian Prescription Database, prescription trends, regional variation, pediatrics, viral wheeze, pharmacoepidemiology