A Study to Determine Safety and Immunogenicity of the Candidate COVID-19 Vaccine AZD1222 Delivered by Aerosol in Healthy Adult Volunteers

This is a Phase I, open label non-randomised dose escalation study in healthy adults aged 30-55 years recruited in the UK. AZD1222 will be administered by inhalation via vibrating mesh nebuliser. The study will assess safety and immunogenicity of AZD1222 with blood and respiratory tract samples. The dose evaluation will be conducted in a single centre supervised by the Chief Investigator and senior clinician experienced in first-in human studies in a cohort of 30 individuals. Approximately 14 days before vaccination, participants will undergo bronchoscopy to sample their lower airways, obtaining bronchoalveolar lavage (BAL), bronchial lining fluid and bronchial tissue. This will be repeated at day +21 and day +182 post-vaccination. The dose escalation cohort will proceed through low (1x10\^9), medium (5x10\^9) and high (1x10\^10 vp) dose as follows: The first participant will receive the low dose and be invited to enter information on local and systemic reactions into a diary that evening and daily thereafter for 6 days. At 48 hours post-vaccination, the team will call the first participant and go through their diary. If the reactions are Grade 1-2 or transient Grade 3 that resolved within 24 hours, two further participants will receive the same dose. At 48 hours post-vaccination, the team will call participants 2 and 3 to go through their diaries. Provided there are no safety concerns, the fourth participant can proceed to receive the medium dose. The steps above will be repeated in order to escalate to the highest dose (1x 10\^10 vp). Provided there are no safety concerns outlined, a further 6 participants will be vaccinated at the maximum tolerated dose - a total of 9 individuals vaccinated with the maximum tolerated dose. The DSMB chair will review safety data before each dose escalation and the full DSMB will periodically assess safety data every 4-8 weeks and/or as required.