Randomized Controlled Trial
Study population and setting
This study was a phase 1 clinical trial including 45 healthy adults between the ages of 18 and 55 years old divided evenly into three groups receiving low, medium, and high doses of Moderna’s mRNA-1273 vaccine in two injections 28 days apart. This analysis includes results through follow-up on day 57.
Summary of Main Findings
Following the first vaccination, antibody responses increased in a dose dependent fashion, with seroconversion in all participants by day 15. Antibody titers increased dose-dependently again after the second dose vaccination. Neutralizing antibodies were detected in all participants after the second dose via two methods. This supports the need for a two-dose vaccination schedule. Neutralizing antibodies in trial participants reached similar levels to those in convalescent serum samples. The most common adverse events included fatigue, chills, headache, myalgia, and pain at injection site, with a greater incidence following the second vaccine dose. All 15 participants in the medium dose group and 14/15 in the high dose group reported solicited systemic adverse events following the second dose. The highest number of overall adverse events was in the high dose group, and 3/15 in this group reported severe adverse events, including fever.
This study was an example of deployment of a vaccine for human clinical trials in record time, taking only two months to accomplish a task that normally takes years to complete. The safety profile of this vaccine is similar to that of other previously published Moderna influenza mRNA vaccines. The mRNA-1273 vaccine proved to be immunogenic in all participants, with all showing binding and neutralizing antibody responses. These responses were similar to antibody levels detected in convalescent serum specimens.
This trial included a small number of participants, which is consistent with phase 1 study design. However, 89% of participants were white. More diversity is needed in the phase 2 cohort, especially since SARS-CoV-2 has disproportionately affected minority populations in the US. Additionally, most patients were around 30 years of age, while the older population is a group that needs the most protection from the virus. There were a few instances of severe adverse events reported in the high dose group. Additionally, no detection of a T-cell response was mentioned for the high dose group.
First report of results from the mRNA-1273 vaccine’s phase 1 trial, with promising findings warranting proceeding to phase 2 trials.
This review was posted on: 18 July 2020