The high prevalence of respiratory symptoms following acute SARS-CoV-2 infection has raised concerns about the virus’s long-term impact on lung health. Many individuals who recover experience persistent issues like cough, wheezing, and shortness of breath. This constellation of symptoms closely resembles asthma, prompting the question of whether COVID-19 can lead to the development of a new, chronic asthmatic condition. Research suggests that while not always classic asthma, the infection can trigger a chronic state of airway dysfunction that functionally mimics it.
How COVID-19 Can Trigger Airway Hyperresponsiveness
The SARS-CoV-2 virus initiates an intense inflammatory response, which is the primary driver of persistent respiratory problems. The virus targets cells lining the airways and lungs by binding to the Angiotensin-Converting Enzyme 2 (ACE2) receptor. This initial cellular damage and the resulting immune system overreaction lead to prolonged inflammation in the bronchioles.
This persistent post-viral inflammation can result in airway hyperresponsiveness (AHR). AHR is a state where the airways become overly sensitive and constrict easily in response to non-allergic triggers, such as cold air, exercise, or strong odors. Damage to the epithelial lining of the bronchioles makes these airways vulnerable and prone to spasm, which presents with wheezing and shortness of breath, similar to asthma symptoms.
The infection may also lead to the activation of mast cells in the airways, which release inflammatory mediators like histamine. This contributes to the heightened inflammatory state, mucus overproduction, and airway constriction. Studies show that COVID-19 infection is associated with an increased risk of developing new-onset asthma. This is sometimes linked to eosinophilic inflammation, a specific type of immune cell activity commonly seen in allergic asthma. The incidence of new-onset asthma has been reported to be more than double in those who have had COVID-19 compared to controls.
Distinguishing Persistent Symptoms from New-Onset Asthma
It is important to differentiate between transient respiratory symptoms that linger after an infection and a formal, chronic diagnosis of asthma. Many post-COVID patients experience a persistent dry cough or temporary shortness of breath that is part of “Long COVID” or Post-Acute Sequelae of SARS-CoV-2 infection (PASC). These symptoms may gradually resolve over several weeks or months.
A true asthma diagnosis requires evidence of chronic, variable, and reversible airway obstruction. The symptoms—wheezing, chest tightness, and dyspnea—must be recurrent and often worsen at night or with physical activity. If respiratory symptoms persist for more than 8 to 12 weeks, a comprehensive respiratory evaluation is necessary.
Some post-COVID patients with long-lasting respiratory issues may not meet the full criteria for classic asthma. Instead, they may have conditions like post-infectious cough syndrome or dysfunctional breathing. The significant overlap between Long COVID respiratory dysfunction and asthma symptoms makes accurate clinical assessment challenging. The diagnosis hinges on the stability and duration of the symptoms, moving beyond the acute phase of the viral illness.
Clinical Tools for Diagnosis
A physician utilizes specific objective tests to confirm a diagnosis of new-onset asthma or AHR following a COVID-19 infection. The primary tool is spirometry, a lung function test that measures how much air a person can inhale and exhale, and how quickly air can be exhaled. Spirometry assesses for variable expiratory airflow limitation, a hallmark of asthma.
If initial spirometry results are inconclusive, a Methacholine Challenge Test (MCT) may be performed to confirm airway hyperresponsiveness. During this test, a patient inhales increasing doses of methacholine, a substance that causes airways to narrow in people with AHR. Measuring fractional exhaled nitric oxide (FeNO) can also provide information, as it measures the level of nitric oxide in the breath, which is often elevated with airway inflammation. These objective measurements are used to tailor the treatment plan.
Treatment Approaches for Post-COVID Respiratory Concerns
Once a persistent respiratory issue is identified, therapeutic strategies focus on reducing inflammation and controlling symptoms. Inhaled corticosteroids (ICS) are often the first-line treatment. They work directly in the airways to decrease inflammation and sensitivity, helping manage the underlying post-viral inflammation causing the chronic symptoms.
Short-acting bronchodilators, often called “rescue inhalers,” are prescribed for immediate relief of sudden symptoms like wheezing or shortness of breath. These medications quickly relax the muscles around the airways to open them up when needed. Additionally, non-pharmacological interventions, such as pulmonary rehabilitation, are beneficial for improving lung capacity and respiratory muscle strength. This rehabilitation includes structured breathing exercises and light physical activity to address the deconditioning that frequently accompanies persistent post-COVID symptoms.