As scientists scramble to understand what the real-world implications are from the many novel mutations seen in Omicron, the new SARS-CoV-2 variant, both Pfizer and Moderna are racing to update their mRNA vaccines. Although it is still unknown how well current COVID-19 vaccines protect from Omicron, drug makers are already preparing new mRNA formulations just in case.
“From the beginning, we have said that as we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves,” says CEO of Moderna, Stéphane Bancel. “The mutations in the Omicron variant are concerning and for several days, we have been moving as fast as possible to execute our strategy to address this variant.”
Within days of the Omicron SARS-CoV-2 variant being identified mRNA vaccine maker Moderna responded with a multi-pronged development approach. As well as starting lab-work on an Omicron-specific mRNA vaccine, the company is rapidly looking at how effectively its previously developed Beta and Delta variant-specific mRNA formulations will work against Omicron.
“We have three lines of defense that we are advancing in parallel: we have already evaluated a higher dose booster of mRNA-1273 (100 µg), second, we are already studying two multi-valent booster candidates in the clinic that were designed to anticipate mutations such as those that have emerged in the Omicron variant and data is expected in the coming weeks, and third, we are rapidly advancing a Omicron-specific booster candidate (mRNA-1273.529),” says Bancel in a statement released barely 48 hours after the new variant was reported to the World Health Organization.
BioNTech, the German company that developed the world’s first mRNA COVID-19 vaccine in association with Pfizer, also swiftly responded to the emergence of the Omicron variant. It is currently conducting lab experiments to determine what kind of resistance this new variant may have to its current mRNA COVID-19 vaccine.
“Pfizer and BioNTech have taken actions months ago to be able to adapt the mRNA vaccine within six weeks and ship initial batches within 100 days in the event of an escape variant,” BioNTech recently said in a statement.
What happened to the Delta variant-specific COVID-19 vaccines?
Early on in 2021, as several novel SARS-CoV-2 variants appeared, vaccine makers leapt to action announcing the development of new mRNA formulations. Both Pfizer and Moderna revealed the rapid development of vaccines specifically designed to target Alpha, Beta and Delta variants.
By August these variant-specific mRNA vaccines commenced human trials. But as time passed, and real-world data accumulated, it became clear that while the Delta variant was much more transmissible than prior iterations of the virus, our current vaccines still worked incredibly well.
In October Philip Dormitzer, Pfizer’s chief scientific officer of viral vaccines and mRNA, indicated the company had shifted its COVID variant development strategy. Instead of actively working to create a Delta variant vaccine it was now using these new formulations as a dress rehearsal in case of the need for a new vaccine in light of a truly vaccine-evasive variant emerging.
“We want to practise all aspects of executing a strain change — the preclinical research, the manufacturing, the clinical testing and the regulatory submissions — so that if we do see a variant out there that truly escapes vaccine immunity, we’re ready to go fast,” Dormitzer said recently to Nature.
Moderna is in a similar position, although it says its new formulations could still be effective against future variants, including Omicron. One of its new formulations was designed to specifically target eight key spike protein mutations seen in Beta and Delta variants.
Moderna’s new Beta/Delta mRNA formulation is already in advanced stages of human clinical trials with more than 500 people enrolled in the study. The company says it is possible this vaccine could provide protection from the Omicron variant, and studies are underway exploring this particular possibility.
Regardless of the clinical success of these previously developed variant-specific vaccines, the last six months has offered drug makers a perfect test bed for refining its responses to newly emerging SARS-CoV-2 variants. In many ways the world has been fortunate that, so far, the SARS-CoV-2 virus has not mutated into a form that evades our current immunity (derived either from vaccines or infections).
Over the coming weeks and months we will learn how well our current vaccines can deal with the new Omicron variant. And if this new variant proves able to slip past our immune protections then scientists are ready to pull the trigger on new targeted vaccines.
