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Our take —

By utilizing a vaccine construct design that has previously been shown to be safe and generate a moderate immune response to MERS (another coronavirus), the researchers were able to combine a phase 1 and 2 trial together, which may speed up the process for identifying if this vaccine will be effective against COVID-19 infection.

Study design

Randomized Controlled Trial

Study population and setting

This is a phase I/II clinical trial examining the safety and ability to generate an immune response to SARS-CoV-2 of an attenuated adenovirus vaccine that produces the spike (S) protein of SARS-CoV-2. This same strategy has been used to generate a Middle Eastern Respiratory Syndrom (MERS) vaccine, which was found to be safe and generated moderate immune responses to MERS (another coronavirus). The trial aims to recruit 1112 volunteers (age 18-55 years) that will be randomly assigned to 4 study groups. One group will receive two doses of the Covid vaccine. The other groups will all receive either one dose of the Covid vaccine, or a dose of MenACWY (a vaccine against Meningococcal bacteria) as a control. The study is being done in the United Kingdom, and has started recruiting volunteers in April 2020. The study will last 6 months.

Summary of Main Findings

N/A, study incomplete

Study Strengths

The sample size will be large and is examining two dose strategies of a single dose, known as a “prime boost” strategy. The size of the study will allow for analysis of accurate immunogenicity for the single dose regimen, which has shown promise in MERS using a similar construct. By combining the phase 1 and 2 stages of the vaccine approval process, it may speed up the regulatory process to see if the vaccine is likely to be effective in preventing infection.


Primary findings will not be for 6 months, however, safety analyses will be done at days 7 and 28, as well as 6 months.

Value added

There is currently no approved, effective vaccine available for SARS-CoV-2 infection.