Dose, Safety and Pathogenicity of SARS-CoV-2 (COVID-19) Omicron Virus (BA.5)

Inclusion Criteria:

• Written informed consent

• Adult male or female aged between 18 and 40 years

• A total body weight ≥50 kg and body mass index (BMI) ≥18 kg/m2 and ≤28kg/m2. Theupper limit of BMI may be increased to ≤30kg/m2 at the PI's discretion, in the caseof physically fit muscular individuals.

• In good health with no history, or current evidence, of clinically significantmedical conditions, and no clinically significant test abnormalities that willinterfere with participant safety.

• Documented medical history

• Adherence to contraception requirements

• Serosuitable for the challenge virus

• Participants must have been previously vaccinated with a COVID-19 vaccine licensedfor use in the UK and completed the course

Exclusion Criteria:

• History of, or currently active, symptoms or signs suggestive of upper or lowerrespiratory tract (LRT) infection within 4 weeks prior to the first study visit.

• Any history or evidence of any clinically significant or currently active disease.

• Any participants who have smoked ≥5 pack years at any time.

• Female participants who are breastfeeding, or have been pregnant within 6 monthsprior to the study, or have a positive pregnancy test at any point during screeningor prior to inoculation.

• Any history of anaphylaxis and/or a any history of severe allergic reaction.

• Venous access deemed inadequate for the phlebotomy and cannulation demands of thestudy.

• History of severe COVID-19 or severe complication of any other viral disease.

• Participants with no knowledge of their family history, as deemed appropriate by thePI

• Significant abnormality of the nose, includes loss of or alterations in smell ortaste,nasal polyps, epistaxis, nasal or sinus surgery.

• Recent vaccinations or intention to receive vaccination before the Day 28 follow upvisit. Receipt of COVID-19 vaccine in the last 3 months prior to inoculation and/ora diagnosis of COVID 19 confirmed by a physician within the last 6 months prior toscreening or at any time between screening and quarantine admission.

• Receipt of blood or blood products, or loss (including blood donations) of 550 mL ormore of blood during the 3 months prior to the planned inoculation or planned duringthe 3 months after the final visit.

• Recent receipt of investigational drugs or challenge viruses.

• Use or anticipated use during the conduct of the study of concomitant medications (prescription and/or non-prescription), including vitamins or herbal and dietarysupplements within the specified windows.

• Positive drugs of abuse test or recent history or presence of alcohol addiction

• A forced expiratory volume in 1 second (FEV1) <80%.

• Positive HIV, hepatitis B virus, or hepatitis C virus test.

• Presence of fever, defined as participant presenting with a temperature reading of ≥37.9°C on Day -2/-1 and/or pre-inoculation on Day 0.

• Those employed or immediate relatives of those employed at hVIVO or the sponsor.

• Any other reason, in the opinion of the investigator deems the participantunsuitable for the study

• Sensitivity to any of the study interventions, challenge agent or components thereof (including lactose), or drug or other allergy that, in the opinion of thePI/investigator, contraindicates participation in the study.