mRNA COVID vaccines: Omicron variant tests platform adaptability and regulatory flexibility

Over the last week, more new cases of the COVID-19 Omicron variant have been detected across the globe. While we don't yet know how serious this new variant will be, experts are concerned that the number of variations to the COVID-19 spike protein which are present in the Omicron variant may mean that current vaccines are less effective than they have been against the "wild type" and previous variants. 

Amid this concern, vaccine makers have each been quick to announce a double pronged strategy. With research already underway to assess the effectiveness of current vaccines against the Omicron variant, Moderna, Pfizer-BioNTech, Johnson & Johnson and AstraZeneca have each announced they are working on new Omicron specific COVID vaccines.  

As we discussed earlier this year in our mini series focussing on mRNA (link here), the mRNA platform technology used in the Moderna and Pfizer-BioNTech vaccines can broadly be described as a "plug and play" technology. If you have the genetic sequence of the protein you want to produce in the body, it is relatively quick and simple to design and synthesise an mRNA for it. This speed of design is one of the most attractive features of mRNA as a platform (not only for vaccines, but also for a variety of other uses including treatment of genetic disease and cancer immunotherapy). The Omicron variant (also known as B.1.1.529) was first spotted in genome-sequencing data from Botswana and the availability of this sequence data has enabled vaccine scientists to quickly begin work on new vaccines.  

However, how quickly an Omicron specific mRNA vaccine can be brought to market depends not only on the agility of the vaccine companies and the adaptability of the vaccine platforms, but also on the flexibility of regulators. The scramble to bring new Omicron specific COVID vaccines to market raises some interesting regulatory questions, in particular how the current medicines regulatory framework should apply to vaccines for new variants. As has been well publicised, the Omicron variant includes  more than 30 mutations to the spike protein (the SARS-CoV-2 protein which current vaccines are designed to generate an immune response against). Regulators could potentially therefore consider a change in the mRNA code of an authorised vaccine as a new medicinal product, requiring new clinical trials to demonstrate safety, efficacy and immunogenicity. However, in the context of COVID-19 vaccines, regulators have been willing to take a more flexible approach. This is an issue my colleagues Julian Hitchcock and Hugo Kent-Egan considered in some detail just last month which you can view here.

As more data emerges on the Omicron variant over the coming weeks, we will continue to watch with interest as vaccine manufacturers and regulators react.