Trial ISRCTN69254139, EudraCT: 2020-005085-33
Publication Liu X, Lancet, 2022
Dates: 2021-02-11 to 2021-02-26
Funding: Public/non profit (UK Vaccine Task Force (VTF) and National Institute for Health Research (NIHR))
Conflict of interest: Yes

Methods
RCT
Location : Multicenter / UK
Follow-up duration (months): 8.3
• ChAdOx1-S/ChAdOx1-S (n=115)
• ChAdOx1-S/BNT162b2 (n=114)
• BNT162b2/BNT162b2 (n=119)
• BNT162b2/ChAdOx1-S (n=115)
Inclusion criteria
  • COVID-19 vaccine-naïve adults aged 50 years and over
  • none or well-controlled mild-moderate comorbidities
Exclusion criteria
  • Previous laboratory confirmed SARS-CoV-2 infection
  • history of anaphylaxis
  • history of allergy to a vaccine ingredient
  • pregnancy
  • breastfeeding or intent to conceive
  • current use of anticoagulants
Interventions
Intervention
1 IM dose of 5.5×10^10 vp ChAdOx1 and 1 IM dose of 30 mcg BNT162b2, 28 days apart
1 IM dose of 30 mcg BNT162b2 and 1 IM dose of 5.5×10^10 vp ChAdOx1, 28 days apart
Control
2 IM doses of 5.5×10^10 vp ChAdOx1, 28 days apart2 IM doses of 30 mcg BNT162b2, 28 days apart
Participants
Randomized
463 participants
Characteristics of participants
Type of participants: Adults
N=463
251 males
Children: 0
Pregnant women: 0
Immunocompromized patients: 0
Mean age:
Age range: 50-68
Description of participants
Adults 50 years or older with no previous SARS-CoV-2 infection, no or well-controlled mild-moderate comorbidities and HIV-negative in 8 centers in the UK
Primary outcome
In the register
Serum level of anti-spike immunoglobulins using ELISA at 56 days
In the report
Serum SARS-CoV-2 anti-spike IgG concentration at 28 days post boost for those with a prime-boost interval of 28 days in participants who were seronegative for COVID infection at baseline
Documents
available

Protocol

Yes. In English

Statistical plan

Yes

Data-sharing stated: Yes, When the trial is complete
Data accessibility: Requests directed to the corresponding author: Matthew D Snape, Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford OX3 9DU, UK, matthew.snape@paediatrics.ox.ac.uk, Phone 01865611400; after approval of a proposal, data can be shared through a secure online platform
Risk of bias
Overall
The overall risk of bias reported in the table corresponds to the highest risk of bias for the outcomes assessed for the systematic review
Some concerns
General comment In addition to the published article with supplementary appendices, the study registries and protocol were used in data extraction and risk of bias assessment. There were no substantive differences in population, procedures, interventions or outcomes between the pre-print article and the trial registry/protocol. The article reports 4 arms of an 8-arm trial in which participants were randomized to either homologous or heterologous vaccination schedules with either a 28 or 84 day interval: the article reports only on the 28 day interval arms. The report is an interim analysis of short-term outcomes, with one-year outcomes not yet measured. The trial achieved its target sample size.
This study was updated on August 23rd, 2021, after publication of trial report.
This trial was further updated on November 9th 2022 after publication of results at a longer follow up.