Most seasonal flu vaccines are designed to train the immune system to defend against three or four different common strains of flu, but a “universal” influenza vaccine might someday provide protection against many more.
The vaccine candidate under investigation, FluMos-v2, was designed by researchers at NIAID’s Vaccine Research Center (VRC). It is an adaptation of an earlier universal flu vaccine candidate, FluMos-v1, which began first-in-human testing in 2021 and is still undergoing trials.
Safety and Efficacy of Flu Vaccines in Animal Trials
FluMos-v2 is designed to induce antibodies against many different influenza virus strains by displaying part of the influenza virus hemagglutinin (HA) protein in repeating patterns on self-assembling nanoparticle scaffolds. Exposure to these harmless fragments of virus proteins prepares the immune system to recognize and fight the actual virus. When tested in animals, the experimental vaccine resulted in robust antibody responses.
While the FluMos-v1 vaccine candidate displays HA from four strains of influenza virus, FluMos-v2 displays HA from six: four influenza A viruses and two influenza B viruses. The researchers anticipate that this will further broaden vaccine recipients’ immunity, providing protection against a wider variety of influenza viruses.
The new clinical trial is expected to enroll 24 healthy volunteers, aged 18-50 years, who will receive two intramuscular injections of the FluMos-v2 vaccine candidate. These injections will be given 16 weeks apart.
At first, participants will be enrolled in the lower dose group (60 mcg per vaccination). If no safety concerns are identified after at least three participants have received this dose, enrollment will begin in the higher dose (180 mcg per vaccination) group. The study team plans to enroll 12 participants in each dosage group.
For 40 weeks after their first vaccination, participants will receive regular follow-up phone calls and examinations to track their responses to the experimental vaccine. Blood samples will be taken during study visits to measure any immune responses to the vaccine candidate.
- Trial to Evaluate the Safety, Tolerability, and Immunogenicity of a Mosaic Hexavalent Influenza Vaccine VRC-FLUMOS0116-00-VP (FluMos-v2) in Healthy Adults – (https://www.clinicaltrials.gov/study/NCT05968989)