heterologous boost immunization with ad5-ncov after three-dose priming with an inactivated sars-cov-2 vaccine

Conditions: COVID-19

Summary: this is an open-label, randomized, parallel-controlled clinical trial to evaluate the safety and immunogenicity of heterologous prime-boost immunization with an aerosolized (ad5-ncov-ih) or intramuscular (ad5-ncov-im) ad5-ncov after three-dose priming with an inactivated covid-19 vaccine (coronavac) in adults aged 18 years and above. a total of 360 subjects will be included. approximately 210 subjects who have completed three doses of coronavac more than 6 months ago in the prior clinical trial and other 150 eligible subjects will be recruited and randomized respectively in a ratio of 1:1:1 to receive a booster dose of ad5-ncov-ih or ad5-ncov-im or icv. the occurrence of adverse reactions within 28 days and serious adverse events within 6 months after vaccination will be observed in all participants. in addition, blood and saliva samples will be collected from all participants on the day 0 before and 14, 28 days and 3, 6 months after the booster vaccination. each subject will remain in this study for approximately 6 months.


Eligibility criteria:
inclusion criteria: * health subjects aged ≥18 years * the subject can provide with informed consent and sign informed consent form (icf). * the subjects are able to and willing to comply with the requirements of the clinical trial program and could complete the 6-month follow-up of the study. * participants who have received three-dose of inactivated sars-cov-2 vaccine more than 6 months ago. exclusion criteria: * have the medical history or family history of convulsion, epilepsy, encephalopathy and psychosis. * be allergic to any component of the research vaccines, or used to have a history of hypersensitivity or serious reactions to vaccination. * vaccine-related sae occurred after previous vaccination with covid-19 vaccine. * women with positive urine pregnancy test or in lactation. * have acute febrile diseases or infectious diseases or have a history of sars. * axillary temperature\>37.0℃ * have serious cardiovascular diseases, such as arrhythmia, conduction block, myocardial infarction, severe hypertension that cannot be controlled by medication (systolic blood pressure ≥180mmhg and/or diastolic blood pressure ≥110mmhg when measured in the field) * have severe chronic diseases or condition is not stable, such as asthma, diabetes, thyroid disease * congenital or acquired angioedema / neuroedema. * have the history of urticaria 1 year before. * have asplenia or functional asplenia. * patients with chronic obstructive pulmonary disease, pulmonary fibrosis and other pulmonary abnormalities. * have history of sars-cov-2 infection or covid-19. * have symptoms of upper respiratory tract infection. * have traveled to medium or high risk areas or traveled abroad in the past 21 days, and epidemiologically contacted with sars-cov-2. * any medical, psychological, social, or other conditions that, in the investigator's judgment, are inconsistent with the protocol or affect the subject's informed consent.

Keywords: sars-cov-2 ad5-ncov inactivated vaccine safety immunogenicity