- Clinical investigators and laboratory team were blinded to group allocation
- Using block randomisation (block sizes=2 and 4) stratified by study group and study site, “participants were randomly assigned (1:1) to receive either the ChAdOx1 nCoV-19 vaccine or the MenACWY vaccine”--The MenACWY vaccine was used as a placebo to induce the same local systemic reactions which are often associated with viral vector vaccines, maintaining blinding


Smith College

- Study design and participants
- Randomisation and masking
- Procedures
- Outcomes
- Results

Methods of Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial

Folegatti, Pedro  M. “Safety and Immunogenicity of the ChAdOx1 NCoV-19 Vaccine against SARS-CoV-2: a Preliminary Report of a Phase 1/2, Single-Blind, Randomised Controlled Trial.” The Lancet, vol. 396, no. 10249, 15 Aug. 2020, pp. 467–478., www.sciencedirect.com/science/article/pii/S0140673620316044. 

Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial

- Phase 1/2, participant blinded, multicentre, randomised, controlled trial--Took place across 5 centres in the UK
- Participants were 18-55 years old and recruited through local advertisements--Underwent screening (medical history, blood test, urine test, and including COVID-19 screening) to ensure participants didn’t have other medical conditions


Study design and participants

Randomisation and masking

- Primary outcome was to see the confirmed COVID-19 cases that were symptomatic virologically to able to use the developing vaccine  & test the safety of the vaccine to see if there were any serious harmful effects

- Secondary outcomes include the safety, reactogenicity, and immunogenicity 
of ChAdOx1 nCoV-19



Outcomes

In a Phase 1/2 trial conducted between April 23 and May 21, 2020, participants were assigned to receive either the ChAdOx1 nCoV-19 or the MenACWY vaccine. A subset of participants (56 in the ChAdOx1 nCoV-19 group and 57 in the MenACWY group) took paracetamol. Participants who did not take paracetamol in both groups reported mild to moderate pain after vaccination. The use of paracetamol mitigated these local reactions: 50% of those receiving the ChAdOx1 nCoV-19 vaccine with paracetamol and 32% of those receiving the MenACWY vaccine with paracetamol reported less pain. Furthermore, less tenderness was reported in the groups taking paracetamol compared to those who did not.

ChAdOx1 nCoV-19 Phase 1/2 Trial Results: Paracetamol Effects on Pain and Tenderness

In the phase 1/2 trial, the ChAdOx1 nCoV-19 vaccine (a chimpanzee adenovirus vector) was administered as a single intramuscular injection to the deltoid area at a dose of $$ 5 	imes 10^{10} $$ viral particles. Participants were recruited into four groups, with blood drawn from all of them:
- Group 1: Received the vaccine only, with early follow-up visits.
- Group 2: Had higher blood volumes drawn to assess humoral and cellular immunogenicity.
- Group 3: Consisted of 10 participants who received a booster after the first dose, with follow-ups similar to Group 1.

Additionally, paracetamol was administered at two out of the five trial sites before and after vaccination to manage vaccine-associated reactions.

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