Kathrin Jansen, Pfizer Inc, poses for a portrait in one of her labs in Pearl River, New York.Carlo Allegri | ReutersThe mRNA technology used to develop the Pfizer-BioNTech Covid-19 vaccine could also help create “more potent” seasonal flu shots, Kathrin Jansen, head of Pfizer’s vaccine research and development, told CNBC.How well flu vaccines work can vary from season to season. But generally, flu inoculations reduce the risk of illness from influenza viruses by between 40% and 60%, according to the Centers for Disease Control and Prevention.Jansen said the reason why flu vaccine effectiveness varies is due to the fact that influenza viruses are always changing and a strain that was common in a previous season may not be as prevalent in the next. Scientists have to constantly monitor strains and select which ones will be included in the flu vaccine each year.Sometimes scientists make selections that don’t match well, Jansen said. But with the flexibility of mRNA technology, scientists could quickly “pivot” and adjust the flu vaccine to match the more dominant strain, she said.”I think the great success of the mRNA vaccines in addressing Covid-19 has clearly opened up a large number of possibilities,” Jansen said in comments that aired Tuesday during CNBC’s Healthy Returns Summit.”We want to have better vaccines for older individuals” who are at risk for severe disease, she said in the interview with CNBC’s Meg Tirrell. “This is in my mind a very powerful approach to get us to ultimately more potent seasonal influenza vaccines.”Jansen’s comments come after Pfizer had huge success with its mRNA-based Covid-19 vaccine.Messenger RNA, or mRNA, technology has been under development for years, but Pfizer’s and Moderna’s Covid-19 vaccines are the first time mRNA has been cleared for use in humans. The mRNA-based Covid vaccine works by tricking the body to produce a harmless piece of the virus, triggering an immune response. It’s said to be easier to produce over traditional vaccines, which generally use a dead or weakened virus to produce an immune response.Pfizer and its German partner BioNTech announced plans to develop a coronavirus vaccine in March of last year and submitted an application to the Food and Drug Administration for emergency use authorization in November.The two-dose vaccine, given three weeks apart, was found in a clinical trial to be about 95% effective.In releasing its first-quarter earnings report last week, Pfizer said it expects full-year sales of $26 billion from the vaccine, up from its previous forecast of about $15 billion. It expects an adjusted pretax profit in the high 20% range of revenue for the vaccine.Pfizer executives told investors that they also hope to make improvements over current flu vaccines. They said given the strong immune response for the Covid-19 vaccine, they hope it will be the same for an mRNA-based flu vaccine. Rival Moderna is also working on a flu vaccine using mRNA technology. Stay connected with Healthy ReturnsFor a front row seat at CNBC Events, you can hear directly from the visionary executives, innovators, leaders and influencers taking the stage in “The Keynote Podcast.” Listen now, however you get your podcasts.For more exclusive insights from our reporters and speakers, sign up for our Healthy Returns newsletter to get the latest delivered straight to your inbox weekly.