Biotechnology company Moderna has revealed more data from its now-completed Phase 3 COVID-19 vaccine trial. The vaccine is reportedly 94.1 percent effective at preventing COVID-19 and 100 percent effective at preventing severe cases of the disease. An FDA review evaluating Emergency Use Authorization is now scheduled for December 17.
In mid-November Moderna announced the results of its interim Phase 3 trial data analysis. Now the company has revealed the large trial is complete, with market approval submissions sent to regulatory bodies around the world.
Moderna’s COVID-19 vaccine, along with Pfizer’s vaccine, is based on new mRNA technology. These novel mRNA vaccines essentially deliver a manufacturing blueprint to cells in the form of RNA, directing them to produce a viral protein. The immune system then learns to recognize and attack this foreign protein, so when a body is subsequently invaded by the targeted virus there are antibodies already trained to respond.
Moderna’s Phase 3 trial recruited 30,000 participants in the United States. The primary efficacy analysis announced by the company reveals 196 cases of COVID-19 were detected in the trial, with only 11 of those positive cases observed in the vaccine cohort. The final efficacy result is claimed to be 94.1 percent.
A secondary endpoint tracking severe COVID-19 cases reveals 30 severe cases observed in the trial cohort and one COVID-19 death. All severe cases and the single death occurred in the placebo group.
Penny Ward, from King’s College London, suggests this particular finding is encouraging. If a vaccine prevents severe disease it can, at the very least, reduce the load this pandemic is having on hospitals. However, without data on asymptomatic cases it is unclear whether the vaccine is preventing infection, which is vital if the vaccine is to suppress viral transmission and end the pandemic.
“Prevention of severe disease and hospitalization can be expected to significantly reduce pressure on overstretched health services, provided that a sufficient proportion of the high risk population can be vaccinated,” explains Ward. “The protocol was not designed to demonstrate impact of vaccination on asymptomatic infection, or on transmission of disease from a vaccinated person to others and so the potential to use this vaccine for outbreak control cannot be estimated.”
The final results of the Phase 3 trial are yet to be published in a peer-reviewed journal, but Raina MacIntyre, an infectious diseases expert from the University of New South Wales, says the current data promisingly establishes the feasibility of mRNA-based COVID-19 vaccines. However, there are plenty of questions that remain.
“We do need to see the peer-reviewed publication of the Phase 3 trial, and be mindful that the longer-term efficacy is unknown,” says MacIntyre. “Current trials are only reporting efficacy at three months or so. We need to know the duration of immunity over one to five years, and that data will take time to accrue.”
The U.S. Food and Drug Administration (FDA) will convene its Vaccines and Related Biological Products Advisory Committee (VRBPAC) on December 17 and discuss Moderna’s emergency use authorization (EUA) request. The committee will then provide recommendations to the FDA, with a final EUA decision to be determined soon after the meeting.
Pfizer’s similar mRNA COVID-19 vaccine is set for VRBPAC discussions on December 10, so it is possible that both vaccines will begin public distribution in the United States before the end of the year. In the interest of full transparency both meetings will be livestreamed on FDA social media channels.
“The FDA understands there is tremendous public interest regarding vaccines for COVID-19,” says Stephen Hahn, FDA Commissioner. “We remain committed to keeping the public informed about the evaluation of the data of a potential COVID-19 vaccine, so that once available, the public and the medical community can have trust and confidence in receiving the vaccine for our families and ourselves.”
