MF59 Adjuvanted Seasonal and Pandemic Influenza Vaccines Increase Immune Responses

Seqirus presented data from various clinical studies demonstrating the ability of an MF59® adjuvanted influenza vaccine to increase immune responses when used in both seasonal and pandemic influenza vaccines, across pediatric and adult populations.

MF59 is an oil-in-water emulsion of squalene oil. Squalene, a naturally occurring substance found in humans, animals, and plants, is highly purified for the vaccine manufacturing process, says the Centers for Disease Control and Prevention. 

Adjuvanted influenza vaccines have demonstrated the ability to enhance the production of immune cells in the body and generate more cross-reactive antibodies against influenza virus strains that have mutated, compared to a non-adjuvanted standard-dose vaccine, said Seqirus in an August 30, 2019, press release.

This is important news since pandemic influenza, as with seasonal influenza, is a contagious airborne respiratory disease that is unpredictable and can occur in any age group or any population worldwide. 

These studies found that when an adjuvant such as MF59 is added to a quadrivalent, adjuvanted seasonal influenza vaccine:

• Induced a higher immune response upon two revaccination studies as demonstrated for both homologous and heterologous strains in children (6 months to 72 months old) compared to a non-adjuvanted influenza vaccine.
• Produced a greater magnitude of cross-reactive antibody responses compared to a non-adjuvanted influenza vaccine in children with lower preexisting antibody titers, regardless of age (6 months through 23 months old or 36 months through 71 months old) or vaccination history.

"These studies show that the use of MF59 adjuvant technology can broaden the immune response against influenza viruses," said Russell Basser, MD, Chief Scientist and Senior Vice President of Research and Development at Seqirus. “MF59 adjuvanted seasonal influenza vaccines have a demonstrated safety profile, with more than 100 million doses distributed since the trivalent formulation was first licensed in 1997.”

Additionally, the MF59 adjuvant, combined with a cell-based pandemic influenza A (H5N1) vaccine candidate, was found to induce antibodies that may enhance the immune response against heterologous A (H5N1) strains.

In these clinical studies that examined a first-of-its-kind A (H5N1) adjuvanted,13 cell-based pandemic influenza vaccine, results showed:

• Increased immune responses against heterologous A (H5N1) strains in adults (18 to < 65 years old) and the elderly (≥ 65 years of age) with a full-dose vaccination (7.5 μg hemagglutinin (HA) of H5N1 with 0.25 mL MF59® for a total injection volume of 0.5 mL) 
• Increased immune responses against heterologous A (H5N1) strains in children (6 months to £ 17 years old) with a full-dose vaccination (7.5 μg hemagglutinin (HA) of H5N1 with 0.25 mL MF59® for a total injection volume of 0.5 mL).

Since influenza A (H5N1) viruses have high pandemic potential, vaccines need to be rapidly produced when these strains emerge. Pandemic influenza vaccines with MF59 adjuvant require less antigen per vaccine dose compared to most seasonal formulations, allowing for more rapid vaccine availability.

MF59 adjuvanted vaccine is an important part of pandemic preparedness planning as it has been shown to generate high levels of cross-reactive antibodies against five separate genetic clades of A (H5N1) virus in both pediatric and adult populations, highlighting the potential public health benefits of pandemic vaccine stockpiling.

"The data presented complements previous clinical studies that emphasize the important role of innovative technologies, such as the MF59® adjuvant, in broadening and enhancing the immune response against evolving seasonal and pandemic influenza viruses," said Anjana Narain, Executive Vice President at Seqirus.

The risk of influenza-associated morbidity and mortality is potentially higher with pandemic influenza than with seasonal influenza because of the lack of existing immunity to the virus in the general human population.

An influenza pandemic requires rapid production of very large quantities of vaccine, and Seqirus has the capability to enhance vaccine production by using cell-based vaccine manufacturing in the event of a pandemic as a result of its public-private partnership with the U.S. Biomedical Advanced Research and Development Authority (BARDA).

The U.S. Food and Drug Administration (FDA) recently accepted the supplemental Biologics License Application (sBLA) for the first-ever adjuvanted, cell-based influenza vaccine against the influenza A (H5N1) strain, said the company.

About the Influenza A (H5N1) Vaccine:

• Influenza A (H5N1) Monovalent Vaccine, Adjuvanted is a pandemic influenza vaccine developed by Seqirus. 
• This is the first and only adjuvanted, cell-based pandemic vaccine to provide active immunization against the influenza A virus H5N1 strain. 
• Seqirus has combined two technologies—MF59® adjuvant and cell-based antigen manufacturing—to create this first-of-its-kind pandemic influenza vaccine.

Seqirus is part of CSL Limited, headquartered in Melbourne, Australia. The CSL Group of companies employs more than 22,000 people with operations in more than 60 countries.

Published by Precision Vaccinations