Trial ISRCTN27841311; EudraCT 2021-001275-16
Publication Stuart A, Lancet, 2021
Dates: 2021-04-19 to 2021-05-14
Funding: Mixed (UK Government through the National Institute for Health Research, the Vaccine Task Force, and the Coalition for Epidemic Preparedness Innovations.NVX vaccine was supplied for use in the trial by Novavax.)
Conflict of interest: Yes

Methods
RCT
Location : Multicenter / UK
Follow-up duration (months): 3
ChAdOx1 nCoV-19/NVX-CoV2373 (n=179) ChAdOx1 nCoV-19/mRNA-1273 (n=181) ChAdOx1 nCoV-19/ChAdOx1 nCoV-19 (n=180)
Inclusion criteria
  • 50 years or older
  • having received a single dose of ChAdOx1 by routine immunisation 8–12 weeks earlier
Exclusion criteria
  • History of confirmed SARS-CoV-2 infection
  • comorbidities that were considered severe or poorly controlled
  • anaphylaxis or allergy to a vaccine component
  • pregnancy, or intent to conceive
  • breastfeeding
  • use of anticoagulants
Interventions
Intervention
1 IM dose ChAdOx 5x10^¹⁰ vp, 1 IM dose NVX-CoV2373 5 mcg SARS-CoV-2 rS + 50 mcg Matrix-M1 adjuvant, 56-84 days apart
1 IM dose ChAdOx 5x10^¹⁰ vp, 1 IM dose mRNA-1273 0.10mg, 56-84 days apart
Control
2 IM doses ChAdOx 5x10^¹⁰ vp, 56-84 days apart
Participants
Randomized
540 participants
Characteristics of participants
Type of participants: Older adults
N=540
299 males
Children: 0
Pregnant women: 0
Immunocompromized patients: 0
Mean age:
Age range: 50.1-74.6
Description of participants
Healthy adults over 50 years previously vaccinated with one dose of ChAdOx1 nCoV-19 in 9 centres in the UK
Primary outcome
In the register
Quantity of anti-spike immunoglobulins measured with ELISA at Day 28
In the report
Geometric mean ratio (GMR) of serum SARS-CoV-2 anti-spike IgG concentrations measured by ELISA in heterologous versus homologous schedules at 28 days after the second dose
Documents
available

Protocol

Yes. In English

Statistical plan

Yes

Data-sharing stated: Yes, when the trial is complete
Data accessibility: Individual participant data will be made available when the trial is complete, upon requests directed to the corresponding author; after approval of a proposal, data can be shared through a secure online platform. Corresponding author: Dr Matthew D Snape, matthew.snape@paediatrics.ox.ac.uk
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, the supplementary materials, prospective study registry, and protocol were used in data extraction and risk of bias assessment. The target sample size specified in the registry was achieved. There were no important differences between protocol/registry and published report in population, procedures, or interventions. The primary and secondary outcomes in the article reflect those in the prospective registry.