study to evaluate the inhaled recombinant covid-19 vaccine (adenovirus type 5 vector) on the protective-efficacy in adults (seihope)

Conditions: COVID-19

Summary: this phase iii clinical trial is an endpoint-driven randomized, double-blind, parallel-controlled, multicenter clinical trial, and around 13,000 subjects aged 18 years and above who have previously received 1 dose of intramuscular ad5-ncov will be recruited. volunteers should have been vaccinated with intramuscular ad5-ncov \> 56 days prior to enrollment. all subjects will receive 1 dose of investigational vaccine or placebo through nebulized inhalation. the ratio of subjects in the vaccine group and placebo group is 1:1 and the efficacy and safety of the investigational vaccine will be followed up for 52 weeks after vaccination.


Eligibility criteria:
inclusion criteria: * adult volunteers aged 18 years and above who have received 1 dose of intramuscular ad5-ncov \> 56 days at the enrollment. * volunteers who have provided informed consent and signed the informed consent form. * volunteers who are able and willing to comply with the requirements of the clinical study protocol, and can complete the entire follow-up period of this study. exclusion criteria: * allergic to the active ingredient, any non-active ingredient, or substances used in the manufacturing process, or developed an allergy to similar vaccines in the past. * history of severe anaphylactic reaction to vaccines (e.g., acute anaphylactic reactions, angioedema, dyspnea). * history or family history of seizures, epilepsy, encephalopathy, or psychosis. * severe nasal or oral diseases, such as acute rhinitis (sinusitis), allergic rhinitis, oral ulcers, throat redness, and swelling. * history of a definite diagnosis of covid-19. * positive sars-cov-2 n antibody rapid screening kit (igg and igm) results. * received covid-19 vaccine other than ad5-ncov. * axillary temperature \> 37.0°c. * severe cardiovascular diseases, such as arrhythmia, conduction block, myocardial infarction, or severe hypertension and cannot be controlled by drugs. * lung function abnormalities such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. * acute febrile illness, symptoms of upper respiratory tract infection, or infectious diseases. * severe chronic diseases, or diseases of the progressive stage that cannot be steadily controlled, such as diabetes or thyroid disorders. * asplenia or functional asplenia. * thrombocytopenia or other coagulation disorder. * received immunosuppressant or immunomodulatory therapy (continuous oral or intravenous infusion for more than 14 days), anti-allergic therapy, cytotoxic therapy within the past 6 months. inhalational and local steroids are allowed. * received blood products within 4 months before receiving the investigational vaccine. * received other vaccines within the past 14 days or plan to receive other vaccines 14 days after scheduled immunization with the investigational vaccine. * volunteers under antituberculous treatment or with active tuberculosis. * received blood/plasma products or immunoglobulin 60 days before immunization with the investigational vaccine or planned to receive blood/plasma products or immunoglobulin during the entire study period. * females who are positive for the urine pregnancy test, pregnant, or breastfeeding, or females who plan to conceive within 3 months (urine pregnancy test will only be performed in female volunteers of childbearing age). * volunteers who are judged by the investigator with any contradiction to the study protocol or affected the signing of informed consent due to various medical, psychological,social, or other conditions.

Keywords: covid-19 vaccine inhalation ad5 efficacy safety immunogenicity