Study Design and Participants
- Multicenter, randomized, double-blind, placebo-controlled trial
- Evaluating safety, reactogenicity and immunogenicity of Ad26.COV2.S at intramuscularly at doses 5x10^10 or 1x10^11 vp 
-Single dose or two-dose schedules 8 weeks apart
- Cohort 1a &1b of adults aged 18-55 and Cohort 3 adults > 65 years old
Randomization and Blinding
- Patients randomly assigned to either one dose or two dose schedule with all possible combinations of high dose, low dose and placebo
-Sponsor and Statisticians group-unblinded for interim analysis after 29 day visit.
Procedures
- S-specific binding bodies were measured by ELISA
- SARS-COV2 neutralizing antibody tigers measured in microneutralization wtVNA
- SARS-COV2 S-specific T cell responses were measured by ICS
Statistical Methods


Ad26.COV2.S Phase 1/2a Study Methods

- Study Participants
- Vaccine Safety and Reactogenicity of Ad26.COV2.S
- Immunogenicity of Ad26.COV2.S

Ad266.COV2.S Phase 1/2a Study Results

- Investigates the Safety and Immunogenicity of the Ad26.COV2.S vaccine in 3 cohorts of people.
- Administered at dose levels of 5x10^10 or 1x10^11 either as single dose or two doses spaced by 56 days.
- Measured S specific antibodies by ELISA, neutralizing titers by wtVNA and CD4+ Th1 and Th2 and CD8+ immune responses by ICS.
- Concluded that the safety profile and immunogenicity after one dose at the lower dosage were sufficient as a potentially protective vaccine and therefore moved to phase 3 testing. 

- Methods
- Results 
- Discussion

Bowdoin College

- Ad26.COV2.S is a vaccine candidate designed by Johnson & Johnson.
- It utilizes a non-replicating adenovirus 26 as a vector expressing the stabilized pre-fusion SARS-CoV-2 spike protein.
- It entered Phase 3 clinical testing in late September, becoming the fourth large-scale vaccine in phase 3 in the United States.

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From our Literary Review:
Johnson & Johnson vaccine candidate is phase 1/2a randomized, double blinded, placebo-controlled clinical study. The purpose of the study was to assess the safety, reactogenicity and immunogenicity of the Ad26.COV2.S. Ad26.COV2.S is a non-replicating adenovirus. The safety and immunogenicity data collected after only a single dose are supportive for further clinical development of Ad26.COV2.S.It is a 26 based vector aiming to express the spike protein of SARS-CoV-2. 


Ad26.COV2.S (Johnson& Johnson) Vaccine Overview

Sadoff, J., Gars, M. L., Shukarev, G., Heerwegh, D., Truyers, C., Groot, A. M., . . . Schuitemaker, H. (2020). Safety and immunogenicity of the Ad26.COV2.S COVID-19 vaccine candidate: Interim results of a phase 1/2a, double-blind, randomized, placebo-controlled trial. MedRxiv. doi:10.1101/2020.09.23.20199604

Safety and immunogenicity of the Ad26.COV2.S COVID-19 vaccine candidate: interim results of a phase 1/2a, double-blind, randomized, placebo-controlled trial

•  The vaccine uses adenovirus serotype 26 as a vector encoding a prefusion stabilized SARS-CoV-2-spike immunogen, a protein which mediates entry of the SARS-CoV-2 into host cells. 

•  A single immunization induced a neutralizing antibody response and complete protection against SARS-CoV-2 in 5 out of 6 rhesus macaques.

•  The phase 1/2a clinical trial is now underway in Belgium and the United States with phase 3 starting in September if results are positive.

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