Global Strategy for Asthma Management and Prevention
Asthma Definition and Diagnosis
What is asthma?
- Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms, such as wheeze, shortness of breath, chest tightness and cough, that vary over time and in intensity, together with variable expiratory airflow limitation. Airflow limitation may later become persistent.
- Asthma is usually associated with airway hyperresponsiveness and airway inflammation, but these are not necessary or sufficient to make the diagnosis.
- Recognizable clusters of demographic, clinical and/or pathophysiological characteristics are often called ‘asthma phenotypes’; however, these do not correlate strongly with specific pathological processes or treatment responses.
How is asthma diagnosed?
- The diagnosis of asthma is based on the history of characteristic symptom patterns and evidence of variable expiratory airflow limitation. This should be documented from bronchodilator reversibility testing or other tests.
- Test before treating, wherever possible, i.e. document the evidence for the diagnosis of asthma before starting ICS-containing treatment, as it is often more difficult to confirm the diagnosis once asthma control has improved.
- Additional or alternative strategies may be needed to confirm the diagnosis of asthma in particular populations, including patients already on ICS-containing treatment, the elderly, and those in low-resource settings.
Definition of Asthma
Assessment of Asthma
- The level of asthma control is the extent to which the features of asthma can be observed in the patient, or have been reduced or removed by treatment.
- Asthma control is assessed in two domains: symptom control and risk of adverse outcomes. Poor symptom control is burdensome to patients and increases the risk of exacerbations, but patients with good symptom control can still have severe exacerbations.
- The current definition of asthma severity is based on retrospective assessment, after at least 2–3 months of asthma treatment, from the treatment required to control symptoms and exacerbations.
- This definition is clinically useful for severe asthma, as it identifies patients whose asthma is relatively refractory to conventional treatment with a combination of high-dose inhaled corticosteroid (ICS) and a longacting beta2 agonist (LABA) and who may benefit from additional treatment such as biologic therapy. It is important to distinguish between severe asthma and asthma that is uncontrolled due to modifiable factors such as incorrect inhaler technique and/or poor adherence.
- However, the clinical utility of a retrospective definition of mild asthma as ‘easy to treat’ is less clear, as patients with few interval symptoms can have xacerbations triggered by external factors such as viral infections or allergen exposure, and short-acting beta2 agonist (SABA)-only treatment is a significant risk factor for exacerbations.
- In clinical practice and in the general community, the term ‘mild asthma’ is often used to mean infrequent or mild symptoms, and patients often incorrectly assume that it means they are not at risk and do not need ICS containing treatment.
- For these reasons, GINA suggests that the term ‘mild asthma’ should generally be avoided in clinical practice or, if used, qualified with a reminder that patients with infrequent symptoms can still have severe or fatal exacerbations, and that this risk is substantially reduced with ICS-containing treatment.
- GINA is continuing to engage in stakeholder discussions about the definition of mild asthma, to obtain agreement about the implications for clinical practice and clinical research of the changes in knowledge about asthma pathophysiology and treatment since the current definition of asthma severity was published.
How to assess a patient with asthma
- Assess symptom control from the frequency of daytime and night-time asthma symptoms, night waking and activity limitation and, for patients using SABA reliever, their frequency of SABA use. Other symptom control tools include Asthma Control Test (ACT) and Asthma Control Questionnaire (ACQ).
- Also, separately, assess the patient’s risk factors for exacerbations, even if their symptom control is good. Risk factors for exacerbations that are independent of symptom control include not only a history of ≥1 exacerbation in the previous year, but also SABA-only treatment (without any ICS), over-use of SABA, socioeconomic problems, poor adherence, incorrect inhaler technique, low forced expiratory volume in 1 second (FEV1), exposures such as smoking, and blood eosinophilia. To date, there are no suitable composite tools for assessing exacerbation risk.
- Also assess risk factors for persistent airflow limitation and medication side-effects, treatment issues such as inhaler technique and adherence, and comorbidities, and ask the patient about their asthma goals and treatment preferences.
- Once the diagnosis of asthma has been made, the main role of lung function testing is in the assessment of future risk. It should be recorded at diagnosis, 3–6 months after starting treatment, and periodically thereafter.
- Investigate for impaired perception of bronchoconstriction if there are few symptoms but low lung function, and investigate for alternative diagnoses if there are frequent symptoms despite good lung function.
Treating Asthma and Controlling Symptoms
General Principles of Asthma Treatment
Goals of asthma management
- The long-term goals of asthma management are to achieve good symptom control, and to minimize future risk of asthma-related mortality, exacerbations, persistent airflow limitation and side-effects of treatment. The patient’s own goals for their asthma and its treatment should also be identified.
The patient-health professional partnership
- Effective asthma management requires a partnership between the person with asthma (or the parent/caregiver) and their health care providers.
- Teaching communication skills to health care providers may lead to increased patient satisfaction, better health outcomes, and reduced use of healthcare resources.
- The patient’s ‘health literacy’ – that is, the patient’s ability to obtain, process and understand basic health information to make appropriate health decisions – should be taken into account.
Making decisions about asthma treatment
- Asthma treatment is adjusted in a continual cycle of assessment, treatment, and review of the patient’s response in both symptom control and future risk (of exacerbations and side-effects), and of patient preferences.
- For population-level decisions about asthma medications, e.g., choices made by national guidelines, insurers, health maintenance organizations or national formularies, the ‘preferred’ regimens in Steps 1–4 represent the best treatments for most patients, based on evidence from randomized controlled trials, meta-analyses and observational studies about safety, efficacy and effectiveness, with a particular emphasis on symptom burden and exacerbation risk. For Steps 1–5, there are different preferred population-level recommendations for different age-groups (adults/adolescents, children 6–11 years, children 5 years and younger). In Step 5, there are also different preferred population-level recommendations depending on the inflammatory phenotype, Type 2 or non-Type 2.
- For individual patients, shared decision-making about treatment should also take into account any patient characteristics or phenotype that predict the patient’s risk of exacerbations or other adverse outcomes, or their likely response to treatment, together with the patient’s goals or concerns and practical issues (inhaler technique, adherence, medication access and cost to the patient).
- For safety, GINA does not recommend treatment of asthma in adults, adolescents or children 6–11 years with SABA alone. Instead, they should receive ICS-containing treatment to reduce their risk of serious exacerbations and to control symptoms.
- ICS-containing treatment can be delivered either with regular daily treatment or, in adults and adolescents with mild asthma, with as-needed low-dose ICS-formoterol taken whenever needed for symptom relief. For children with mild asthma, ICS can be taken whenever the SABA reliever is taken.
- Reduction in severe exacerbations is a high priority across treatment steps, to reduce the risk and burden to patients and the burden to the health system, and to reduce the need for oral corticosteroids (OCS), which have cumulative long-term adverse effects.
Treatment tracks for adults and adolescents
- For clarity, the treatment figure for adults and adolescents shows two ‘tracks’, largely based on the choice of reliever. Treatment may be stepped up or down within a track using the same reliever at each step, or treatment may be switched between tracks, according to the individual patient’s needs.
- Track 1, in which the reliever is low-dose ICS-formoterol, is the preferred approach recommended by GINA. When a patient at any step has asthma symptoms, they use low-dose ICS-formoterol as needed for symptom relief. In Steps 3–5, they also take ICS-formoterol as regular daily treatment. This approach is preferred because it reduces the risk of severe exacerbations compared with using a SABA reliever, with similar symptom control, and because of the simplicity for patients and clinicians of needing only a single medication across treatment steps 1–4. Medications and doses for Track 1 are explained in Box 3-15, p.80.
- Track 2, in which the reliever is a SABA or ICS-SABA, is an alternative if Track 1 is not possible, or if a patient is stable, with good adherence and no exacerbations in the past year on their current therapy. In Step 1, the patient takes a SABA and a low-dose ICS together for symptom relief (in combination if available, or with the ICS taken immediately after the SABA). In Steps 2–5, the reliever is a SABA or combination ICS-SABA. Before considering a SABA reliever, consider whether the patient is likely to be adherent with their ICS-containing treatment, as otherwise they would be at higher risk of exacerbations.
Steps 1 and 2
- Track 1: In adults and adolescents with mild asthma or who are taking SABA alone, treatment with as-needed-only low-dose ICS-formoterol reduces the risk of severe exacerbations and emergency department visits or hospitalizations by about two-thirds compared with SABA-only treatment. As-needed-only low-dose ICS-formoterol reduces the risk of emergency department visits and hospitalizations compared with daily ICS, with no clinically important difference in symptom control. In patients previously using SABA alone, as-needed low-dose ICSformoterol also significantly reduces the risk of severe exacerbations needing OCS, compared with daily ICS.
- Track 2: Treatment with regular daily low-dose ICS plus as-needed SABA is highly effective in reducing asthma symptoms and reducing the risk of asthma-related exacerbations, hospitalization and death. However, adherence with ICS in the community is poor, leaving patients taking SABA alone and at increased risk of exacerbations. While as-needed-only ICS-SABA could be an option at this step, current evidence is limited to small studies that were not powered to detect differences in exacerbation rates.
Stepping up if asthma remains uncontrolled despite good adherence and inhaler technique
- Before considering any step up, first confirm that the symptoms are due to asthma and identify and address common problems such as inhaler technique, adherence, allergen exposure and multimorbidity; provide patient education.
- For adults and adolescents, the preferred Step 3 treatment is the Track 1 regimen with low-dose ICS-formoterol as maintenance-and-reliever therapy (MART). This reduces the risk of severe exacerbations, with similar or better symptom control, compared with maintenance treatment using a combination of an ICS and a long-acting beta2 agonist (LABA) as controller, plus as-needed SABA. If needed, the maintenance dose of ICS-formoterol can be increased to medium (i.e. Step 4) by increasing the number of maintenance inhalations. MART is also a preferred treatment option at Steps 3 and 4 for children 6–11 years, with a lower dose ICS-formoterol inhaler.
- ICS-formoterol should not be used as the reliever for patients taking a different ICS-LABA maintenance treatment, because clinical evidence for safety and efficacy is lacking.
- Other Step 3 options for adults and adolescents in Track 2, and in children, include maintenance ICS-LABA plus asneeded SABA or plus as-needed ICS-SABA (if available) or, for children 6–11 years, medium-dose ICS plus asneeded SABA.
- For children, try other controller options at the same step before stepping up.
Stepping down to find the minimum effective dose
- Once good asthma control has been achieved and maintained for 2–3 months, consider stepping down gradually to find the patient’s lowest treatment that controls both symptoms and exacerbations
- Provide the patient with a written asthma action plan, monitor closely, and schedule a follow-up visit.
- Do not completely withdraw ICS unless this is needed temporarily to confirm the diagnosis of asthma.
For all patients with asthma, providing asthma education and training in essential skills
- After choosing the right class of medication for the patient, the choice of inhaler device depends on which inhalers are available for the patient for that medication, which of these inhalers the patient can use correctly after training, and their relative environmental impact. Check inhaler technique frequently.
- Provide inhaler skills training: this is essential for medications to be effective, but technique is often incorrect.
- Encourage adherence with controller medication, even when symptoms are infrequent.
- Provide training in asthma self-management (self-monitoring of symptoms and/or peak expiratory flow (PEF), written asthma action plan and regular medical review) to control symptoms and minimize the risk of exacerbations.
For patients with one or more risk factors for exacerbations
- Prescribe ICS-containing medication, preferably from Track 1 options, i.e., with as-needed low-dose ICS-formoterol as reliever; provide a written asthma action plan; and arrange review more frequently than for lower-risk patients.
- Identify and address modifiable risk factors (e.g., smoking, low lung function, over-use of SABA).
- Consider non-pharmacological strategies and interventions to assist with symptom control and risk reduction, (e.g., smoking cessation advice, breathing exercises, some avoidance strategies).
Difficult-to-treat and severe asthma
- Patients who have poor symptom control and/or exacerbations, despite medium- or high-dose ICS-LABA treatment, should be assessed for contributing factors, and asthma treatment optimized.
- If the problems continue or diagnosis is uncertain, refer to a specialist center for phenotypic assessment and consideration of add-on therapy including biologics.
Guided Asthma Self-Management Education and Skills Training
- As with other chronic diseases, people with asthma need education and skills training to manage it well. This is most effectively achieved through a partnership between the patient and their health care providers. The essential components for this include:
- Choosing the most appropriate inhaler for the patient’s asthma treatment: consider available devices, cost, the ability of the patient to use the inhaler after training, environmental impact, and patient satisfaction
- Skills training to use inhaler devices effectively
- Encouraging adherence with medications, appointments and other advice, within an agreed management strategy
- Asthma information
- Training in guided self-management, with self-monitoring of symptoms or peak flow; a written asthma action plan to show how to recognize and respond to worsening asthma; and regular review by a health care provider or trained health care worker.
- In developing, customizing and evaluating self-management interventions for different cultures, sociocultural factors should be taken into account.
Managing Astma with Multimorbidity And In Specific Populations
- Multimorbidity is common in patients with chronic diseases such as asthma. It is important to identify and manage multimorbidity, as it contributes to impaired quality of life, increased healthcare utilization, and adverse effects of medications. In addition, comorbidities such as rhinosinusitis, obesity and gastro-esophageal reflux disease (GERD) may contribute to respiratory symptoms and some contribute to poor asthma control.
- For patients with dyspnea or wheezing on exertion:
- Distinguish between exercise-induced bronchoconstriction (EIB) and symptoms that result from obesity or a lack of fitness or are the result of alternative conditions such as inducible laryngeal obstruction.
- Provide advice about preventing and managing EIB.
- All adolescents and adults with asthma should receive ICS-containing treatment to reduce their risk of severe exacerbations. It should be taken every day or, as an alternative in mild asthma, by as-needed ICS-formoterol for symptom relief.
- Refer patients with difficult-to-treat or severe asthma to a specialist or severe asthma service, after addressing common problems such as incorrect diagnosis, incorrect inhaler technique, ongoing environmental exposures, and poor adherence (see Section 3.5, p.120).
Difficult to Treat and Severe Asthma in Adults and Adolescents
What are difficult to treat and severe asthma?
- Difficult-to-treat asthma is asthma that is uncontrolled despite prescribing of medium or high-dose ICS-LABA treatment or that requires high-dose ICS-LABA treatment to maintain good symptom control and reduce exacerbations. It does not mean a ‘difficult patient’.
- Severe asthma is asthma that is uncontrolled despite adherence with optimized high-dose ICS-LABA therapy and treatment of contributory factors, or that worsens when high-dose treatment is decreased. Approximately 3–10% of people with asthma have severe asthma.
- Severe asthma places a large physical, mental, emotional, social and economic burden on patients. It is often associated with multimorbidity.
How should these patients be assessed?
- Assess all patients with difficult-to-treat asthma to confirm the diagnosis of asthma, and to identify and manage factors that may be contributing to symptoms, poor quality of life, or exacerbations.
- Refer for expert advice at any stage, or if asthma does not improve in response to optimizing treatment.
- For patients with persistent symptoms and/or exacerbations despite high-dose ICS, the clinical or inflammatory phenotype should be assessed, as this may guide the selection of add-on treatment.
Management of severe asthma
- Depending on the inflammatory phenotype and other clinical features, add-on treatments for severe asthma include LAMA, LTRA, low-dose azithromycin (adults), and biologic agents for severe asthma.
- Low-dose maintenance OCS should be considered only as a last resort if no other options are available, because of their serious long-term side-effects.
- Assess the response to any add-on treatment, stop ineffective treatments, and consider other options.
- Utilize specialist multidisciplinary team care for severe asthma, if available.
- For patients with severe asthma, continue to optimize patient care in collaboration with the primary care clinician, and taking into account the patient’s social and emotional needs.
- Invite patients with severe asthma to enroll in a registry or clinical trial, if available and relevant, to help fill evidence gaps.
Duagnosis and Initial Treatment of Adults with Features of Asthma and COPD or Both
Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous and overlapping conditions
- ‘Asthma’ and ‘COPD’ are umbrella labels for heterogeneous conditions characterized by chronic airway and/or lung disease. Asthma and COPD each include several different clinical phenotypes, and are likely to have several different underlying mechanisms, some of which may be common to both asthma and COPD.
- Symptoms of asthma and COPD may be similar, and the diagnostic criteria overlap.
Why are the labels ‘asthma’ and ‘COPD’ still important?
- There are extremely important differences in evidence-based treatment recommendations for asthma and COPD: treatment with a long-acting beta2 agonist (LABA) and/or long-acting muscarinic antagonist (LAMA) alone (i.e., without inhaled corticosteroids [ICS]) is recommended as initial treatment in COPD but contraindicated in asthma due to the risk of severe exacerbations and death.
- These risks are also seen in patients who have diagnoses of both asthma and COPD, making it important to identify adult patients who, for safety, should not be treated with long-acting bronchodilators alone.
- In COPD, high-dose ICS should not be used because of the risk of pneumonia.
Many patients have features of both asthma and COPD
- Distinguishing asthma from COPD can be difficult, particularly in smokers and older adults, and some patients may have features of both asthma and COPD.
- The terms ‘asthma-COPD overlap’ (ACO) or ‘asthma+COPD’ are simple descriptors for patients who have features of both asthma and COPD.
- These terms do not refer to a single disease entity. They include patients with several clinical phenotypes that are likely caused by a range of different underlying mechanisms.
- More research is needed to better define these phenotypes and mechanisms, but in the meantime, safety of pharmacologic treatment is a high priority.
- Diagnosis in patients with chronic respiratory symptoms involves a stepwise approach, first recognizing that the patient is likely to have chronic airways disease, then syndromic categorization as characteristic asthma, characteristic COPD, with features of both or having other conditions such as bronchiectasis.
- Lung function testing is essential for confirming persistent airflow limitation, but variable airflow obstruction can be detected with serial peak flow measurements and/or measurements before and after bronchodilator.
Initial treatment for safety and clinical efficacy
- For asthma: ICS are essential either alone or in combination with a long-acting bronchodilator (LABA), to reduce the risk of severe exacerbations and death. Do not treat with LABA and/or LAMA alone, without ICS.
- For patients with features of both asthma and COPD, treat as asthma. ICS-containing therapy is important to reduce the risk of severe exacerbations and death. Do not give LABA and/or LAMA alone without ICS.
- For COPD: Treat according to current GOLD 2023721 recommendations, i.e. initial treatment with LAMA and LABA, plus as-needed SABA; with ICS for patients with any hospitalizations, ≥2 exacerbations/year requiring OCS, or blood eosinophils ≥300/μl.
- All patients: provide structured education especially focusing on inhaler technique and adherence; assess for, and treat, other clinical problems, including advice about smoking cessation, immunizations, physical activity, and management of multimorbidity.
- Specialist referral for additional investigations in patients with asthma+COPD is encouraged, as they often have worse outcomes than patients with asthma or COPD alone.
Children 6 Years and Younger
- Recurrent wheezing occurs in a large proportion of children 5 years and younger, typically with viral upper respiratory tract infections. It is difficult to discern when this is the initial presentation of asthma.
- Previous classifications of wheezing phenotypes (episodic wheeze and multiple-trigger wheeze; or transient wheeze, persistent wheeze and late-onset wheeze) do not appear to identify stable phenotypes, and their clinical usefulness is uncertain. However, emerging research suggest that more clinically relevant phenotypes will be described and phenotype-directed therapy possible.
- A diagnosis of asthma in young children with a history of wheezing is more likely if they have:
- Wheezing or coughing that occurs with exercise, laughing or crying, or in the absence of an apparent respiratory infection
- A history of other allergic disease (eczema or allergic rhinitis), allergen sensitization or asthma in first-degree relatives
- Clinical improvement during 2–3 months of low-dose inhaled corticosteroid (ICS) treatment plus as-needed short-acting beta2 agonist (SABA) reliever, and worsening after cessation.
Assessment and Management
- The goals of asthma management in young children are similar to those in older patients:
- To achieve good control of symptoms and maintain normal activity levels
- To minimize the risk of asthma flare-ups, impaired lung development and medication side-effects.
- Wheezing episodes in young children should be treated initially with inhaled SABA, regardless of whether the diagnosis of asthma has been made. However, for initial episodes of wheeze in children <1 year in the setting of infectious bronchiolitis, SABAs are generally ineffective.
- A trial of low-dose ICS treatment should be given if the symptom pattern suggests asthma, alternative diagnoses have been excluded and respiratory symptoms are uncontrolled and/or wheezing episodes are frequent or severe.
- Response to treatment should be reviewed before deciding whether to continue it. If the response is absent or incomplete, reconsider alternative diagnoses.
- The choice of inhaler device should be based on the child’s age and capability. The preferred device is a pressurized metered dose inhaler and spacer, with face mask for <3 years and mouthpiece for most children aged 3–5 years. Children should be switched from a face mask to mouthpiece as soon as they are able to demonstrate good technique.
- Review the need for asthma treatment frequently, as asthma-like symptoms remit in many young children.
Worsening Asthma and Exacerbations
- Symptoms of exacerbation in young children
- Early symptoms of exacerbations in young children may include increased symptoms; increased coughing, especially at night; lethargy or reduced exercise tolerance; impaired daily activities including feeding; and a poor response to reliever medication.
- Home management in a written asthma action plan
- Give a written asthma action plan to parents/caregivers of young children with asthma so they can recognize an impending severe attack, start treatment, and identify when urgent hospital treatment is required.
- Initial treatment at home is with inhaled short-acting beta2-agonist (SABA), with review after 1 hour or earlier.
- Parents/caregivers should seek urgent medical care if the child is acutely distressed, lethargic, fails to respond to initial bronchodilator therapy, or is worsening, especially in children <1 year of age.
- Medical attention should be sought on the same day if inhaled SABA is needed more often than 3-hourly or for more than 24 hours.
- There is no compelling evidence to support parent/caregiver-initiated oral corticosteroids.
- Management of exacerbations in primary care or acute care facility
- Assess severity of the exacerbation while initiating treatment with SABA (2–6 puffs every 20 minutes for first hour) and oxygen (to maintain saturation 94–98%).
- Recommend immediate transfer to hospital if there is no response to inhaled SABA within 1–2 hours; if the child is unable to speak or drink, has a respiratory rate >40/minute or is cyanosed, if resources are lacking in the home, or if oxygen saturation is <92% on room air.
- Consider oral prednisone/prednisolone 1–2 mg/kg/day for children attending an Emergency Department (ED) or admitted to hospital, up to a maximum of 20 mg/day for children aged 0–2 years, and 30 mg/day for children aged 3–5 years, for up to 5 days; or dexamethasone 0.6 mg/kg/day for 2 days. If there is failure of resolution, or relapse of symptoms with dexamethasone, consideration should be given to switching to prednisolone.
- Arrange early follow-up after an exacerbation
- Children who have experienced an asthma exacerbation are at risk of further exacerbations. Arrange follow-up within 1–2 days of an exacerbation and again 1–2 months later to plan ongoing asthma management.
Primary Prevention of Asthma in Children
- The development and persistence of asthma are driven by gene–environment interactions. For children, a ‘window of opportunity’ to prevent asthma exists in utero and in early life, but intervention studies are limited.
- With regard to allergen avoidance strategies aimed at preventing asthma in children:
- Strategies directed at a single allergen have not been effective in reducing the incidence of asthma
- Multifaceted strategies may be effective, but the essential components have not been identified.
- Current recommendations for preventing asthma in children, based on high-quality evidence or consensus, include:
- Avoid exposure to environmental tobacco smoke during pregnancy and the first year of life.
- Encourage vaginal delivery.
- Where possible, avoid use of broad-spectrum antibiotics during the first year of life.
- Breast-feeding is advised, not for prevention of allergy and asthma, but for its other positive health benefits).
- In order to improve asthma care and patient outcomes, evidence-based recommendations must not only be developed, but also disseminated and implemented at a national and local level, and integrated into clinical practice.
- Recommendations for implementing asthma care strategies are based on many successful programs worldwide.
- Implementation requires an evidence-based strategy involving professional groups and stakeholders, and should take into account local cultural and socioeconomic conditions.
- Cost-effectiveness of implementation programs should be assessed so a decision can be made to pursue or modify them.
- Local adaptation and implementation of asthma care strategies is aided by the use of tools developed for this purpose.
Global Strategy for Asthma Management and Prevention
May 11, 2023
Supplemental Implementation Tools
External Publication Status
Country of Publication
Male, Female, Adolescent, Adult, Child, Older adult
Health Care Settings
Ambulatory, Childcare center
Nurse, nurse practitioner, physician, physician assistant
Diagnosis, Assessment and screening, Treatment, Management, Prevention
D029424 - Pulmonary Disease, Chronic Obstructive, D001249 - Asthma
chronic obstructive pulmonary disease (COPD), asthma, Exacerbations
Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2023.
Updated May 2023. Available from: www.ginasthma.org