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For Seqirus, mRNA Offers The Next Big Breakthrough In Flu Vaccines

Vaccines being packaged
Doses of vaccine being packaged. (Image courtesy Seqirus. Photo by Mehmet Demirci.)

Spare a bit of sympathy for our flu vaccine makers.

Chris Larkins
Chris Larkins, SVP of Global Operations at Seqirus. (Image courtesy Seqirus.)

“For flu, chasing variants is such a challenge in vaccine manufacturing,” said Chris Larkins, SVP of Global Operations at Seqirus, one of the primary producers of flu vaccines worldwide. “The World Health Organization [WHO] has a tough job in predicting which strain is emerging. Then in manufacturing, we’re developing and launching a new product every six months for both the southern and northern hemispheres. It’s exciting, but extremely challenging. Manufacturing windows are tight–we’re producing 90% of supply in a six-month window. It’s an intense manufacturing process, and there’s no safety stock.”

“It all gets used in about 12 weeks,” added David Ross, VP of Commercial Operations, North America at Seqirus. “There’s nothing else like that challenge in manufacturing and distribution.”

David Ross
David Ross, VP of Commercial Operations, North America, at Seqirus. (Image courtesy Seqirus.)

None of those difficulties are anything new for Seqirus, though. The company’s origins go back to 1916, when its parent company CSL Ltd. was founded in Melbourne, Australia, as Commonwealth Serum Laboratories. Seqirus was formed in 2015 when CSL purchased the Novartis influenza vaccines business, including a manufacturing site in Holly Springs, North Carolina. CSL employs around 27,000 people globally, of which 3,300 work for Seqirus, across 20 countries.

Flu took a back seat during the pandemic, but it remains a significant health threat. “Flu is a contagious respiratory disease with effects ranging from potentially minor symptoms to death,” Ross said. “The populations most at risk for mortality are children under three and adults over 65, as well as people with comorbidities. The public health burden in the U.S. is between 10 million and 40 million cases, with 150,000 to 700,000 hospitalizations and 12,000 to 50,000 deaths annually.”

As COVID slowly becomes endemic, that annual flu impact will come back as a top priority, and that’s where Seqirus’ mRNA vaccine research comes in. “Seqirus has been developing a self-amplifying mRNA (sa-mRNA) flu vaccine, the next generation of mRNA technology,” Larkins explained. “There are a lot of potential benefits of the self-amplifying approach. Compared to traditional mRNA vaccines, our sa-mRNA vaccine may possess an overall better immunological efficacy, with the potential to develop effective vaccines with a smaller dosage, which may have a big impact on its safety.”

“One of the things COVID did was educate the population on vaccine technologies,” said Ross. “We see that as an opportunity to continue to educate people about vaccine protection. For over 80 years, the primary vaccine technology has been egg-based, grown in chicken eggs. But there are some limitations to that. As a human virus is grown in an egg, it can adapt, which can lead to a less effective vaccine. We now have technology platforms, including our cell-based technology, designed to be an exact match to the WHO-selected strain, and our MF59 adjuvant, added to the vaccine to boost the immune system’s response.”

Vaccine manufacturing
The Seqirus vaccine manufacturing facility in Holly Springs, North Carolina. (Image courtesy Seqirus. Photo by Mehmet Demirci.)

For some people, an mRNA vaccine could be a tough sell after some of the controversies surrounding the COVID vaccines. “For us, it’s about evidence-based information,” Ross continued. “The best way to combat mis-information is to focus on the science and to share all the information.”

“I think the important thing is for people to know is that influenza vaccines have been around a long time,” added Larkins. “Seqirus has been on the forefront of developing different vaccines for different age groups, including ones that are cell-based for better efficacy and more effective manufacturing. We have three manufacturing plants globally, one of which focuses on cell-based vaccines. When Seqirus was formed, we were producing five million doses a year out of our cell-based manufacturing plant in the U.S., which we’ve now been able to optimize to produce over 50 million doses a year. Making our vaccines in bioreactors helps us improve our volumes and efficiencies since it’s easy to dial production up or down.”

The timing could be just right, as people start once again focusing on illnesses like the flu. “COVID has occupied, and rightly so, the minds of just about everyone,” said Ross. “But flu is still devastating. As the only company totally focused on influenza, our organization is very proud of what we’ve done, and very excited about our differentiated portfolio of influenza vaccines to keep populations safe, including those most vulnerable. “We’re expanding,” added Larkins. “In addition to our existing three manufacturing sites, we’re adding a fourth in Melbourne, Australia. It’s under construction, and will launch production early in 2026. It will be the only cell-based facility in the southern hemisphere.”

Originally published at on May 26, 2022.

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