Inclusion criteria

- Has voluntarily signed the written informed consent

- Male or female aged ≥18 to ≤75 years

- Good general health based upon the results of the medical history, laboratory tests,
physical examination, ENT clinical examination, and vital signs as assessed by the
investigator

- Prior vaccination with at least two doses of any COVID-19 vaccine with last dose
obtained ≥180 days before the planned baseline (Day 0) visit

- Has a personal smartphone, tablet or computer with internet access, and is
considered willing and able to report the data in the ePRO and to comply with the
reporting timelines

- Willing and able to comply with the instructions to participants

- Not of childbearing potential or willing and able to use a highly effective
contraception method consistently and correctly during the entire trial

Exclusion criteria

- Pregnant, planning to become pregnant, or breastfeeding women

- Received any investigational drug < 180 days prior baseline

- Antigen positivity or PCR confirmed SARS-CoV-2 infection less than 180 days apart
from screening or during screening and/or baseline

- Any SARS-CoV vaccination was administrated < 180 days prior the planned baseline
(Day 0) visit

- Any other vaccination within 60 days prior the planned baseline (Day 0) visit

- Administration of immunoglobulins or blood products within 90 days prior baseline

- Current use of immunosuppressant medication (except topical and inhaled steroids,
which are permitted in indications not prohibited in the exclusion criteria)

- Use of steroid nasal sprays within 30 days prior to screening

- Use of any oral or nasal decongestants within 7 days prior to screening

- Any confirmed or suspected immunodeficient state

- Chronic respiratory diseases (except treatment -controlled asthma)

- Severe chronic cardiovascular and endocrinological diseases (e.g., medicine or
insulin treated diabetes), liver and renal insufficiency or serious psychiatric
diseases

- Medication for elevated cholesterol or blood pressure or dietary treated diabetes
or hypothyreosis are not exclusion criteria

- Any diagnosed disease or abnormality in the nasal or upper respiratory tract, such
as acute/chronic rhinosinusitis; nasal polyposis; mucosal pathology or tumor of
nasal cavity, pharynx or nasopharynx; significant obstructive nasal deformity;
recurrent epistaxis; sleep apnea; anosmia

- History of adenoidectomy and/or tonsillectomy are not exclusion criteria

- Severe obesity (BMI ≥ 35)

- Cancer treated within 5 years

- Known allergy/hypersensitivity to any ingredients of the COV2 vaccine

- Previous anaphylactic reaction

- Any clinically significant abnormal finding in the screening laboratory tests

- Inability to sign ICF or to understand and comply with trial related instructions
and requirements

- Individuals who are employees of, or directly affiliated with, the sponsor, or site
staff or their immediate family members.