Originally published at sciencepolicyforall.wordpress.com
On Monday, biotech firm Moderna announced preliminary findings of their COVID-19 vaccine clinical trial demonstrating 94.5% efficacy. Moderna reported that 90 people who had received placebo shots became ill with COVID-19, compared to only 5 in the vaccine group. Moreover, of the 90 positive patients in the placebo group 11 developed severe cases of COVID-19, compared to no severe cases in the treatment group. These findings come a week after Pfizer and Biontech announced that preliminary findings from their own vaccine clinical trial had demonstrated that the vaccine was more than 90% effective.
Both Moderna’s vaccine and the vaccine from Pfizer and Biontech are mRNA vaccines, as opposed to the traditional live attenuated (where a weakened pathogen is given to the patient) or inactivated pathogen (where a dead pathogen is delivered) vaccine models. Instead of using isolated virus, mRNA vaccines deliver a messenger ribonucleic acid molecule that shows cells how to produce specific viral proteins, inducing an immune response resulting in immunity to COVID-19. The vaccines created by Modern and Pfizer are the first mRNA vaccines to be tested in late stage clinical trials and could indicate new strategies for vaccine development moving forward.
While the preliminary results of both vaccines are exciting, questions remain about both vaccines. No actual data have been published outside of press releases, and the safety and efficacy data of both remain unknown. Furthermore, the Pfizer vaccine must stay at -70 degrees Celsius at all times, with the Moderna vaccine requiring a more generous -20 degrees Celsius for long term storage and is stable from 2-8 degrees Celsius for 30 days. This may restrict transport and storage, especially in lower income countries.
It also remains to be seen how many vaccine doses can be produced and how quickly. As Stéphane Bancel, CEO of Moderna, stated, “We don’t have a billion-dose manufacturing capacity sitting idle somewhere”. While Moderna estimates they could produce between 500 million and 1 billion doses in 2021, far more will be required to end the pandemic.
(Jon Cohen, Science Magazine )