- Patients requiring hospitalization at the time of enrolment,- Simultaneous participation in other clinical trials or previous participation within 30 days before inclusion,- Being in any relationship or dependence with the Sponsor, CRO and/or Investigator,- Inability to understand instructions/study documents,- Inability to administer the nasal spray- Specific vulnerable patients: subjects who are detained or committed to institutions by law court or by legal authorities, such as psychiatric wards, prisons or other state institutions- Any additional antihistamine therapy from Day 1 of the trial to Day 16 (locally or systemically applied), any antihistamine therapy 7 days prior to enrolment- Any concurrent nasalia including nasal lavage fluids- Any concurrent anti-COVID therapy (including off-label use) such as (inhalative) corticosteroids or anti-viral and immune-modulatory active substances, for example Sotrovimab, Molnupiravir, Paxlovid (Nirmatrelvir and Ritonavir).- Unvaccinated patients who are eligible for therapy with already approved COVID-19 medicinal products- Females who are pregnant, lactating, or of child-bearing potential and not using an adequate contraceptive method until D60. Females in post-menopausal state may be included.- Having any contraindication for the use of azelastine nasal spray (incl. hypersensitivity to the active substance or other ingredients).

- Patients requiring hospitalization at the time of enrolment,- Simultaneous participation in other clinical trials or previous participation within 30 days before inclusion,- Being in any relationship or dependence with the Sponsor, CRO and/or Investigator,- Inability to understand instructions/study documents,- Inability to administer the nasal spray- Specific vulnerable patients: subjects who are detained or committed to institutions by law court or by legal authorities, such as psychiatric wards, prisons or other state institutions- Any additional antihistamine therapy from Day 1 of the trial to Day 16 (locally or systemically applied), any antihistamine therapy 7 days prior to enrolment- Any concurrent nasalia including nasal lavage fluids- Any concurrent anti-COVID therapy (including off-label use) such as (inhalative) corticosteroids or anti-viral and immune-modulatory active substances, for example Sotrovimab, Molnupiravir, Paxlovid (Nirmatrelvir and Ritonavir).- Unvaccinated patients who are eligible for therapy with already approved COVID-19 medicinal products- Females who are pregnant, lactating, or of child-bearing potential and not using an adequate contraceptive method until D60. Females in post-menopausal state may be included.- Having any contraindication for the use of azelastine nasal spray (incl. hypersensitivity to the active substance or other ingredients).