Data released on 14 July shows that a new COVID-19 vaccine was able to generate a satisfactory immune response.
As with most trials, the vaccine, mRNA-1273, encodes the SARS-CoV-2 spike glycoprotein which mediates host cell attachment and is needed for the virus to enter cells. The Phase I study included 45 healthy volunteers (aged 18 to 55 years) who were split into three groups, with each group receiving either a 25, 100 or 250mcg dose of the vaccine which was administered on days 1 and 29.
The results which cover a period of 43 days after the second vaccination showed that after the first dose, antibody responses were greatest for the two higher strengths and increased further after the second vaccination. In addition, although neutralising antibodies were detected after the first vaccination in less than half of the participants, all had detectable antibodies after the second dose. The vaccine was well tolerated were participants reporting mild-to-moderate severity arthralgia, fatigue and headache with localised mild injection site pain.
The authors report that their findings support the advancement of the vaccine for a Phase II trial (which began in May) and hopefully a Phase III trial starting in July 2020.
Jackson LA et al. An mRNA vaccine against SARS-CoV-2 – Preliminary report. N Engl J Med 2020; July 14: DOI: 10.1056/NEJMoa2022483