COVID-19 initially reduced asthma attacks but widened socioeconomic disparities, study finds

By Pooja Toshniwal PahariaReviewed by Susha Cheriyedath, M.Sc.Feb 25 2026

A six-year analysis from a major Bronx health system reveals how the pandemic reshaped asthma exacerbation patterns, exposing persistent racial disparities and deepening socioeconomic divides in one of the nation’s most vulnerable urban communities.

Study: Effects of COVID-19 pandemic on incidence of asthma exacerbation in an urban population. Image Credit: Prostock-studio / Shutterstock

In a recent study published in the journal Scientific Reports, researchers examined the effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak on asthma exacerbations in a racially and socioeconomically diverse urban population in the Bronx.

Analyzing trends from 2018 to 2024, the team found that asthma exacerbations initially declined following the onset of the pandemic, a change hypothesized to reflect reduced exposure to common triggers rather than a proven causal effect, before gradually returning to pre-pandemic levels. However, this rebound was uneven, with widening gaps linked to income, insurance status, age, and documented unaddressed social needs, underscoring persistent inequities in asthma care.

Asthma Burden and the Disruptive Impact of COVID-19

Asthma remains one of the most common chronic respiratory diseases worldwide. The condition disproportionately affects urban and underserved communities, where environmental exposures, limited access to health resources, and socioeconomic disadvantage often intersect.

Coronavirus disease 2019 (COVID-19) disrupted routine care globally and introduced social and biological stressors that may have reshaped asthma management and exacerbation patterns. Early public health policies, including lockdowns and school closures, were associated with temporary declines in viral spread and air pollution. These changes may have contributed to short-term reductions in asthma flare-ups.

However, delayed care, reduced preventive interventions, and heightened barriers may have counterbalanced these gains, particularly in communities like the Bronx, where asthma burden and social vulnerability are high.

Study Design and Population

Researchers retrospectively analyzed Montefiore Health System records covering a large and socioeconomically diverse Bronx population, an early United States epicenter of COVID-19. The study aimed to assess pandemic-related shifts in asthma exacerbation risk.

The team analyzed electronic health records from 162,113 asthma patients between March 2018 and February 2024. Key variables were validated through regular chart reviews in a subset of patients. Asthma cases and exacerbations were identified using ICD-10 diagnostic codes. Exacerbations were defined by healthcare encounters, including emergency visits, hospitalizations, or systemic corticosteroid treatment codes recorded in the electronic health record.

Study variables included age, sex, ethnicity, race, household income quartile, insurance type, and documented unaddressed social needs.

The primary outcome was the annual proportion of asthma exacerbations per 100 patients, from March to February in each study year. Patients were counted once per year if active in the health system. Logistic regression and difference-in-differences (DiD) analyses compared exacerbation risk before and after COVID-19 onset, contrasting pre-pandemic (2018 to 2020) and late-pandemic (2022 to 2024) periods using odds ratios (OR).

Monthly exacerbation trends were evaluated using an interrupted time-series analysis, excluding March to May 2020 due to major healthcare disruptions and treating March 2020 as the interruption point. Sensitivity analyses included alternative exclusion windows and autoregressive integrated moving average models with exogenous variables.

Pre-Pandemic Disparities in Asthma Exacerbations

The cohort was predominantly female (61 percent), with 40 percent identified as Hispanic, 32 percent as Black, and 9.5 percent as non-Hispanic White. Over half (52 percent) were covered by Medicaid, and nearly one-third were in the two lowest household-income quartiles. Adults comprised 69 percent of participants, while children comprised 31 percent. Exacerbations followed seasonal trends, peaking in early fall and declining during summer months.

Before the pandemic, approximately 25 percent of children and 12 percent of adults experienced annual exacerbations. Higher risk was observed among males (OR 1.37), Medicaid beneficiaries (OR 1.41), individuals in income quartile 2 compared with the highest quartile (OR 1.16), and those with at least one unaddressed social need (OR 1.20). Hispanic (OR 1.47), Black (OR 1.37), and other non-Hispanic racial groups (OR 1.45) had significantly greater odds of exacerbation compared with non-Hispanic White patients.

Post-Pandemic Decline and Uneven Rebound

After March 2020, asthma exacerbations declined sharply in both children and adults. Interrupted time series analyses confirmed significant immediate reductions in monthly rates.

Over time, children’s exacerbation rates rebounded toward pre-pandemic levels by 2023, whereas adult rates remained comparatively lower. The authors interpret this cautiously and suggest it may reflect sustained environmental or behavioral changes rather than confirmed causal mechanisms.

DiD analyses indicated that racial and ethnic disparities persisted but did not significantly widen after the pandemic. In contrast, disparities related to Medicaid coverage, lower- and middle-income quartiles, and unaddressed social needs widened. Sensitivity analyses supported the robustness of these findings.

Implications for Equity in Asthma Care

The findings suggest that COVID-19 acted as both a disruptor and amplifier of existing inequities in asthma care. Although racial and ethnic disparities in exacerbation risk remained largely stable, socioeconomic gaps widened, particularly among Medicaid beneficiaries, certain lower and middle-income groups, children, and individuals with documented unaddressed social needs.

Children experienced a temporary decline followed by a return to baseline exacerbation rates, while adults showed a more sustained reduction. However, the observational design limits causal inference.

The results highlight the importance of addressing housing instability, food insecurity, insurance barriers, and preventive care access. The authors note that documentation of unaddressed social needs was incomplete in many patients, which may affect the precision of the estimate. Broader multicenter studies and a deeper examination of social determinants, including potential links to long COVID, may help inform more equitable asthma care strategies in future public health crises.