There will be 12 study groups and it is anticipated that a total of 12,390 volunteers will be enrolled. Groups 1, 7 & 9 are adults aged 56-69 years; groups 2, 8 & 10 are adults 70 years and over; groups 4, 5 & 6 are adults aged 18-55 years; group 11 is adults aged 18-55 years who have previously received a ChAdOx vectored vaccine; group 12 is HIV positive adults aged 18-55 years.

The vaccine will be administered intramuscularly into the deltoid of the non-dominant arm (preferably).

All subjects will undergo follow-up for a total of 1 year post last vaccination. Additional visits or procedures may be performed at the discretion of the investigators, e.g., further medical history and physical examination, or additional blood tests and other investigations if clinically relevant

Cell-mediated and humoral responses against SARS-Cov-2 These will be measured by the following:

1. Proportion of seroconversion to antibodies (Ab) against SARS-CoV-2 spike protein measured by ELISA.
2. Interferon-gamma enzyme linked immunospot (ELISpot) responses to SARS-CoV-2 spike protein
3. Intracellular Cytokine analyses of CD4 and CD8-specific SARS-CoV-2 spike protein responses
4. Further exploratory immunology including immune responses to a further dose administered via the NHS national roll out

Measured by the following:

1. Occurrence of serious adverse events (SAEs) throughout the study duration
2. Occurrence of solicited local reactogenicity signs and symptoms for 7 days following vaccination
3. Occurrence of solicited systemic signs and symptoms for 7 days following each vaccination
4. Occurrence of unsolicited AEs for 28 days following each vaccination

Inclusion Criteria:

• Adults aged 56 or older (groups 1 and 2)
• Adults aged 18 or older (group 4)
• Children aged 5-12 inclusive (group 3)
• Able and willing (in the Investigator's opinion) to comply with all study requirements.
• Willing to allow the investigators to discuss the volunteer's medical history with their General Practitioner and access all medical records when relevant to study procedures.
• For females of childbearing potential only, willingness to practice continuous effective contraception (see below) during the study and a negative pregnancy test on the day(s) of screening and vaccination.
• Agreement to refrain from blood donation during the course of the study.
• Provide written informed consent.
• Parent/Guardian provides informed consent

Exclusion Criteria:

• Current or planned participation in other clinical trial of an investigational medicinal product
• Prior receipt of any vaccines (licensed or investigational) ≤30 days before enrolment
• Planned receipt of any vaccine other than the study intervention within 30 days before and after each study vaccination.
• Prior receipt of an investigational or licensed vaccine likely to impact on interpretation of the trial data (e.g. Adenovirus vectored vaccines, any coronavirus vaccines).
• Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate.
• Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent severe infections and chronic use (more than 14 days) immunosuppressant medication within the past 6 months (topical steroids are allowed).
• History of allergic disease or reactions likely to be exacerbated by any component of ChAdOx1 nCoV-19 or MenACWY
• Any history of hereditary angioedema or idiopathic angioedema.
• Any history of anaphylaxis.
• Pregnancy, lactation or willingness/intention to become pregnant during the study.
• Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
• History of serious psychiatric condition likely to affect participation in the study.
• Bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture.
• Suspected or known current alcohol abuse as defined by an alcohol intake of greater than 42 units every week.
• Suspected or known injecting drug abuse in the 5 years preceding enrolment.
• Any other significant disease, disorder or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.
• History of laboratory confirmed COVID-19.
• New onset of fever or a cough or shortness of breath since February 2020
• Those who have been at high risk of exposure before enrolment, including but not limited to: close contacts of confirmed COVID-19 cases, anyone who had to self-isolate as a result of a symptomatic household member, frontline healthcare professionals working in A&E, ICU and other higher risk areas and significant exposure associated with travel abroad to high incidence areas since January 2020.
• Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e. warfarin) or novel oral anticoagulants (i.e. apixaban, rivaroxaban, dabigatran and edoxaban) Additional Exclusion criteria to Groups 1 and 2
• Chronic respiratory disease, including asthma
• Severe and/or uncontrolled cardiovascular disease, gastrointestinal disease, liver disease, renal disease, endocrine disorder and neurological illness (mild well controlled comorbidities are allowed)
• Seriously overweight (BMI≥40 Kg/m2)
• History of auto-immune disease

Additional Exclusion Criteria to Group 3

• Chronic medical conditions such as chronic lung disease, chronic liver disease, chronic renal failure, chronic heart disease, congenital genetic syndromes (e.g. Trisomy 21)
• Fulfil any of the contraindications to vaccination as specified in The Green Book

Re-vaccination exclusion criteria (two-dose groups only)

• Anaphylactic reaction following administration of vaccine
• Pregnancy

Inclusion Criteria:

• Adults aged 18 - 55 years (groups 4, 5, 6 and 11)
• Adults aged 56-69 years (groups 1, 7, and 9)
• Adults aged 70 years and older (groups 2, 8, and 10)
• Able and willing (in the Investigator's opinion) to comply with all study requirements.
• Willing to allow the investigators to discuss the volunteer's medical history with their General Practitioner and access all medical records when relevant to study procedures.
• For females of childbearing potential only, willingness to practice continuous effective contraception (see below) during the study and a negative pregnancy test on the day(s) of screening and vaccination.
• Agreement to refrain from blood donation during the course of the study.
• Provide written informed consent.

Additional Inclusion criteria to Group 12 (HIV sub-study):

• HIV positive
• Receiving antiretroviral therapy
• Undetectable HIV viral load
• CD4>350 cells/mL

Exclusion Criteria:

• Participation in COVID-19 prophylactic drug trials for the duration of the study.

Note: Participation in COVID-19 treatment trials is allowed in the event of hospitalisation due to COVID-19. The COV002 study team should be informed as soon as possible.

• Participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study.

Note: Disclosure of serostatus post enrolment may accidently unblind participants to group allocation. Participation in COV002 can only be allowed if volunteers are kept blinded to their serology results from local/national serological surveys

• Receipt of any vaccine (licensed or investigational) other than the study intervention within 30 days before and after each study vaccination, with the exception of the licensed seasonal influenza vaccination and the licensed pneumococcal vaccination. Participants will be encouraged to receive these vaccinations at least 7 days before or after their study vaccine.
• Prior or planned receipt of an investigational or licensed vaccine or product likely to impact on interpretation of the trial data (e.g. Adenovirus vectored vaccines, any coronavirus vaccines). This exclusion criteria will not apply to group 11, as recruitment will be targeted at those volunteers who previously received a ChAdOx1 vectored vaccine.
• Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate.
• Any confirmed or suspected immunosuppressive or immunodeficient state (except group 12, where HIV infected participants are allowed); asplenia; recurrent severe infections and use of immunosuppressant medication within the past 6 months, except topical steroids or short-term oral steroids (course lasting ≤14 days)
• History of allergic disease or reactions likely to be exacerbated by any component of ChAdOx1 nCoV-19 or MenACWY
• Any history of angioedema.
• Any history of anaphylaxis.
• Pregnancy, lactation or willingness/intention to become pregnant during the study.
• Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
• History of serious psychiatric condition likely to affect participation in the study.
• Bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture.
• Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e. warfarin) or novel oral anticoagulants (i.e. apixaban, rivaroxaban, dabigatran and edoxaban)
• Suspected or known current alcohol or drug dependency.
• Any other significant disease, disorder or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.
• Severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, liver disease, renal disease, endocrine disorder and neurological illness (mild/moderate well controlled comorbidities are allowed)
• History of laboratory confirmed COVID-19 (except groups 5d, 5e, 5f, 9, 10 and 11).
• Seropositivity to SARS-CoV-2 before enrolment (except groups 5d, 5e, 5f, 9, 10 and 11)
• NB: volunteers with previous NAAT positive results are also allowed in groups 9, 10 and 11

Additional Exclusion criteria to Groups 4, 6, 9 and 10

• History of allergic disease or reactions likely to be exacerbated by Paracetamol
• Note: Caution should be taken when recommending paracetamol to adults who already take paracetamol chronically

Re-vaccination exclusion criteria (two-dose groups only)

• Anaphylactic reaction following administration of vaccine
• Pregnancy. An exception to this will be prior to receipt of a booster dose at extra visit B. If a pregnant woman has discussed vaccination with their usual clinician (e.g. GP) and chooses to receive a COVID-19 vaccination, this may be administered by the trial team as part of extra visit B. (Protocol 19.0) or as part of the provision of treatment to controls.
• Any AE that in the opinion of the Investigator may affect the safety of the participant or the interpretation of the study results