What is the evidence supporting the use of azelastine (antihistamine nasal spray) to prevent COVID-19 or influenza in patients with a history of allergic rhinitis?

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Azelastine Nasal Spray for COVID-19 and Influenza Prevention

Direct Answer

Azelastine nasal spray shows promising evidence for reducing SARS-CoV-2 infections by approximately 69% in healthy adults, but there is no evidence supporting its use for influenza prevention. 1

Evidence for COVID-19 Prevention

Recent Clinical Trial Data

The most compelling evidence comes from a 2025 phase 2 randomized controlled trial that demonstrated significant prophylactic efficacy:

  • Azelastine 0.1% nasal spray (3 times daily for 56 days) reduced PCR-confirmed SARS-CoV-2 infections from 6.7% to 2.2% (OR 0.31; 95% CI 0.11-0.87) in healthy adults 1

  • Among infected participants, azelastine delayed time to infection by approximately 12 days (mean 31.2 vs 19.5 days) 1

  • The treatment also reduced overall symptomatic respiratory infections (21/227 vs 49/223 participants) and rhinovirus infections (1.8% vs 6.3%) 1

Mechanism Supporting Antiviral Activity

The rationale for COVID-19 prevention stems from azelastine's demonstrated in vitro antiviral activity against SARS-CoV-2 and other respiratory viruses, though the exact mechanism remains under investigation 1

A separate 2024 phase 2 trial in patients with established mild COVID-19 infection showed that azelastine 0.1% nasal spray significantly reduced viral load compared to placebo by day 11 (log10 5.93 vs 5.85 copies/mL, p=0.0041), though this addresses treatment rather than prevention 2

Evidence for Influenza Prevention

No evidence exists supporting azelastine nasal spray for influenza prevention. The available literature focuses exclusively on:

  • Allergic rhinitis treatment 3, 4
  • COVID-19 prevention and treatment 1, 2

The 2020 European Position Paper on Rhinosinusitis makes no mention of azelastine for viral respiratory infection prevention beyond COVID-19 3

Safety Profile

Azelastine demonstrates excellent tolerability in both short-term allergic rhinitis use and extended prophylactic use:

  • Adverse events were comparable between azelastine and placebo groups in the COVID-19 prevention trial 1
  • Common side effects include bitter taste (4.5-19.7%), minimal somnolence (0.4-3%), and epistaxis (≤4.5%) 4, 5
  • No cardiovascular or serious safety concerns emerged in clinical trials 5

Clinical Recommendations

For COVID-19 Prevention in High-Risk Exposure Settings

Consider azelastine 0.1% nasal spray, 2 sprays per nostril 3 times daily, based on the phase 2 trial protocol that demonstrated efficacy 1

Important caveats:

  • This represents emerging evidence from a single-center trial requiring confirmation in larger multicentric studies 1
  • The study population consisted primarily of healthy adults (mean age 33 years), so generalizability to elderly or immunocompromised populations is unknown 1
  • Vaccination remains the primary prevention strategy; azelastine should be considered as adjunctive prophylaxis, not replacement for standard preventive measures 1

For Influenza Prevention

Do not use azelastine nasal spray for influenza prevention as no supporting evidence exists. Standard influenza prevention relies on annual vaccination and antiviral prophylaxis (oseltamivir, zanamivir) in specific high-risk scenarios.

For Patients with Allergic Rhinitis

If prescribing azelastine for its FDA-approved indication (allergic rhinitis), patients may experience the secondary benefit of reduced respiratory viral infections, though this should not be the primary indication 4, 1

Knowledge Gaps

The current evidence base has significant limitations:

  • No head-to-head comparison with other prophylactic strategies (monoclonal antibodies, antiviral medications) 1
  • Unknown efficacy against current SARS-CoV-2 variants as the trial was conducted in 2023-2024 1
  • No data on optimal treatment duration beyond the 56-day protocol studied 1
  • Complete absence of influenza-specific data despite theoretical antiviral mechanisms 1, 5

References

3
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

4
Guideline

Azelastine Nasal Spray for Acute Allergic Rhinitis with Uncontrolled Asthma

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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