Phase III Double-Blind, Placebo-Controlled Study of AZD1222 for the Prevention of COVID-19 in Adults

Clinical Trial Title

A phase III randomized, double-blind, placebo-controlled multicenter study in adults to determine the safety, efficacy, and immunogenicity of AZD1222, a non-replicating ChAdOx1 vector vaccine, for the prevention of COVID-19.

National Clinical Trial Number:


Clinical Trial Protocol Description:

D8110C00001 is a Phase III randomized, double-blind, placebo-controlled multicenter study assessing the safety, efficacy, and immunogenicity of AZD1222 compared to placebo for the prevention of COVID-19. 

Participants will be adults ≥ 18 years of age who are healthy or have medically-stable chronic diseases, and are at increased risk for SARS-CoV-2 acquisition and COVID-19. Approximately 30 000 participants will be randomized in a 2:1 ratio to receive 2 IM doses of either 5 × 1010 vp (nominal, ± 1.5 × 1010 vp) AZD1222 (n = approximately 20 000) or saline placebo (n = approximately 10 000) 4 weeks apart, on Days 1 and 29. Randomization will be stratified by age (≥ 18 to < 65 years, and ≥ 65 years), with at least 25% of participants to be enrolled in the older age stratum. All participants will be assessed for efficacy and safety.

The first participants randomized in each age group, including 1,500 participants 18 to 55 years of age, 750 participants 56 to 69 years of age, and 750 participants ≥ 70 years of age, will also participate in a substudy assessing the reactogenicity and immunogenicity of AZD1222.

A Protocol Safety Review Team will provide safety surveillance during the study. Additionally, an independent COVID-19 Vaccine DSMB organized by the National Institutes of Health, National Institute for Allergy and Infectious Diseases, will provide oversight, to ensure safe and ethical conduct of the study.

Participants will remain on study for 2 years following administration of the first dose of study intervention (Day 730). If AZD1222 is proven to be safe and efficacious based on the primary Clinical Study Protocol - Amendment 2 AstraZeneca AZD1222 - endpoint analysis, following discussion at that time with the US FDA, other Regulators if appropriate, and the COVID-19 Vaccine DSMB, participants allocated to the placebo group may be offered AZD1222 if doses are available. Placebo participants treated with AZD1222 will continue to be followed in the study.

Clinical Trial Eligibility Criteria:

In order to participate you must meet the following criteria:

  • Are an adult, ≥ 18 years of age. Women of child-bearing age are required to use highly effective birth control for at least 28 days prior to vaccination and through 60 days after vaccination.
  • Have increased risk of SARS-CoV-2 infection.
  • Are defined as an adult whose locations or circumstances put them at appreciable risk of exposure to SARS-CoV-2 and COVID-19, based on available risk assessment.
  • Are medically stable such that, according to the judgment of the investigator, hospitalization within the study period is not anticipated and the participant appears likely to be able to remain on study through the end of protocol-specified follow-up.
  • Are able to understand and comply with study requirements/procedures (if applicable, with assistance by caregiver, surrogate, or legally authorized representative) based on the assessment of the investigator

You will be excluded from the study if any of the following criteria apply to you:

  • Have a history of allergy to any component of the vaccine.
  • Have a history of Guillain-Barré syndrome or any other demyelinating condition.
  • Have any confirmed or suspected immunosuppressive or immunodeficient state, including asplenia.
  • Have a history of laboratory-confirmed SARS-CoV-2 infection.
  • Have recurrent severe infections and use of immunosuppressant medication within the past 6 months (≥ 20 mg per day of prednisone or its equivalent, given daily or on alternate days for ≥ 15 days within 30 days prior to administration of study intervention).  The following exceptions are permitted:
    • Topical/inhaled steroids or short-term oral steroids (course lasting ≤ 14 days)
    • Human immunodeficiency virus-positive stable participants on stable antiretroviral therapy
  • Have a history of primary malignancy except for:
    • Malignancy with low potential risk for recurrence after curative treatment (for example, history of childhood leukaemia) or metastasis (for example, indolent prostate cancer) in the opinion of the site investigator.
    • Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease
    • Adequately treated uterine cervical carcinoma in situ without evidence of disease
    • Localized prostate cancer
  • Have a clinically significant bleeding disorder (eg, factor deficiency, coagulopathy, or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venipuncture.
  • Have severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, liver disease, renal disease, endocrine disorder, and neurological illness, as judged by the Investigator. (Mild/moderate well-controlled comorbidities are allowed.)
  • Have received immunoglobulins and/or any blood products within 3 months prior to administration of study intervention or expected receipt during the period of study follow-up.
  • For women only: Are currently pregnant (confirmed with positive pregnancy test) or breast-feeding.

This is a partial list of eligibility requirements. To inquire about your eligibility, please call the contact number provided. If you wish to inquire via email, please include the title of the study in your message.

Study Details

Clinical Trial Investigator

Beverly E. Sha, MD

Contact Information

Beverly E. Sha, MD