Interpreting the Oxford, Moderna COVID-19 Vaccine Data

July 23, 2020

Angela Rasmussen, PhD, explains how preliminary findings for both candidates define their potential for preventing or lessening coronavirus.

On Monday, preliminary results from the phase 1/2 clinical trial of the adenovirus vaccine candidate from the University of Oxford showed healthy adult participants had strong antibody and T cell immune responses up to 56 days in the ongoing study.

The trial, in which 1077 healthy adults in the UK are being assessing for the vaccine comprised of the ChAdOx1 virus for the prevention of SARS-CoV-2, shows enough promise for further assessment and the introduction of older adults in clinical research.

In new data published to The Lancet Monday morning, Oxford investigators led by Professor Andrew Pollard found the chimpanzee-based adenovirus strain that constitutes their vaccine candidate is capable of provoking a T cell response within 14 days of administration, and an antibody response within 28 days.

Investigators expressed the need for greater work to be done prior to confirming the vaccine's benefit in managing COVID-19. However, they conceded the 56-day results show promise.

The week prior, the Moderna candidate mRNA-1273 was reported to have induced immune responses in all 45 of its volunteer patients administered doses in the phase 1, dose-escalation, open-label trial.

New findings showed the vaccine candidate, encoded with a stabilized prefusion SARS-CoV-2 spike protein, induced anti-SARS-CoV-2 immune responses in all of the trial’s participants, without any trial-limiting safety concerns identified.

Investigators described the immunogenicity profile of mRNA-1273 as “rapid and robust,” particularly noting the 100-mcg dose vaccine eliciting high neutralization responses, Th1-skewed CD4 T cell responses, as well as a reactogenicity profile more favorable than the observed higher and lower doses.

The findings, reported by the mRNA-1273 Study Group, supported the advancement of a 100-mcg dose vaccine to a phase 3 trial assessment in later summer 2020, while a phase 2 trial of a pair of different doses of the potential vaccine continue among 600 healthy adults.

What’s to be made of this new data? How does it influence the already unprecedented trend of vaccine development in response to the pandemic?

In an interview with Contagion, Angela Rasmussen, PhD, a virologist from Columbia Public Health, discussed the findings and what may come next in research and progression of vaccine options.