GSK presented positive phase 2 data for its mRNA seasonal influenza (flu) vaccine candidate at the Options XIII Conference for the Control of Influenza.
GSK’s vaccine candidate showed higher immune responses against all influenza strains tested compared to licensed standard dose and high dose inactivated flu vaccines in younger and older adults respectively, and was generally well tolerated. Based on these results, GSK intends to start a phase 3 efficacy trial this month.
This will be the first phase 3 trial of an mRNA flu vaccine designed to target both haemagglutinin (HA) and neuraminidase (NA), the primary surface antigens that cause the flu virus to bind and spread. While licensed flu vaccines primarily target HA, GSK’s vaccine candidate is specifically designed to also target NA. Growing evidence suggests this could help improve protection, illness severity and transmission.
Sanjay Gurunathan, GSK Head of Vaccines and Infectious Diseases Research and Development (R&D), said: ‘These promising data support the potential to better protect people from flu with a vaccine designed to target both HA and NA. With one billion flu cases worldwide each year and up to 650,000 deaths there is a need for next generation vaccine approaches.4 This result is a significant advance in our cutting-edge mRNA programme, and we look forward to starting phase 3 imminently.’
In July 2026, the US Food and Drug Administration (FDA) granted the vaccine candidate Fast Track designation for the targeted age indication, reflecting the urgent need to improve flu protection.
GSK’s investigational mRNA seasonal flu vaccine programme is designed to target haemagglutinin (HA) and neuraminidase (NA). It is part of GSK’s respiratory vaccines research and ongoing work to explore new approaches to seasonal flu prevention. GSK’s investigational mRNA seasonal flu vaccine candidate is not approved anywhere in the world.
