Two recent Phase III mRNA COVID-19 vaccine trials resulted in 95% efficacy and generally well-tolerated safety profiles for vaccines BNT162b2 and mRNA-1273, developed by Pfizer/BioNTech and Moderna, respectively. As no mRNA vaccines had been approved for human use, these clinical trials have created optimism in this research space, says GlobalData, a leading data and analytics company.

Mohamed Abukar, Pharma Analyst at GlobalData, comments: “The storage conditions of mRNA vaccines are a critical issue, with Pfizer’s and Moderna’s vaccines requiring environments of -70°C and -20°C, respectively – although Moderna’s candidate is able to be stored at fridge and room temperatures for short periods of time. These low-temperature storage requirements increase the complexity of logistics, as there may not be enough low-temperature freezers available and shipping will require tracking using GPS-enabled thermal sensors to monitor the temperature of each shipment.”

Vaccine storage is less of an issue for AstraZeneca’s vaccine candidate AZD1222, as it requires storage conditions between 2°C and 8°C, allowing for easier transportation and administration across a variety of settings. However, both mRNA vaccines have superior efficacies compared with AZD1222, which displays an efficacy of 70%.

Abukar continues: “Questions remain over the results obtained in the AZD1222 Phase III study, as the smaller second cohort presented with a superior efficacy of 90% compared with the 62% observed in the first group. However, the second group constitutes participants ages 55 and below, who may be less likely to become critically ill, which could allow for better efficacy results. It is likely that AstraZeneca will conduct a new trial to validate the increased efficacy observed in the older alternatively dosed cohort.”

The Russian adenovirus-based vaccine Sputnik V has also shown an efficacy of 95% in its Phase III trials, which is equal to that of the mRNA vaccines and requires storage conditions of -18°C or lower, similar to that of the Moderna vaccine, with further trials ongoing testing a freeze-dried version that could be stored between 2°C and 8°C. A higher storage temperature could be a competitive edge for the distribution of these vaccines.

Abukar concludes: “Pressure is now on for countries to issue approvals; the FDA has scheduled public hearings for both Pfizer/BioNTech and Moderna, on 10 and 17 December, respectively. Given the urgency of the pandemic and the need for a vaccine along with the efficacy results, it is likely that these will receive approval.”