NIH-funding Seasonal Flu Vaccines Test With Experimental Adjuvants

Novel adjuvants have shown promise in animal models at enhancing the immune response to influenza vaccines

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The National Institute of Allergy and Infectious Diseases (NIAID) announced it is funding a phase 1 clinical trial evaluating 2 seasonal influenza vaccines.

In a press release published on August 8, 2019, this study will evaluate flu shots administered with or without novel adjuvants, for their safety and ability to generate an immune response. 

This limited trial will enroll 240 healthy volunteers ages 18 to 5 years at Vaccine and Treatment Evaluation Units, which is a network of clinical trial sites funded by NIAID. 

Volunteers will be randomly assigned to receive 1-dose of either the Fluzone® Quadrivalent Influenza Vaccine or Flublok® Quadrivalent Influenza Vaccine. 

These flu vaccines are manufactured by Sanofi Pasteur and are reformulated each year to best match the anticipated seasonal influenza strains selected by the World Health Organization.

Participants will receive the northern hemisphere 2018-2019 influenza season formulations of Fluzone and Flublok at the start of the trial. Fluzone is made from inactivated influenza viruses grown in chicken eggs. 

Flublok is an egg-free recombinant vaccine comprised of a surface protein of influenza virus, hemagglutinin, specifically engineered to achieve an exact genetic match to the WHO-selected influenza strains each year. The Flublok proteins are manufactured in insect cells using a genetically engineered baculovirus.

The vaccine will be given alone or in combination with either the AF03 or the Advax-CpG55.2™ adjuvant. The two novel adjuvants being tested have shown promise in animal models at enhancing the immune response to influenza vaccines. 

In additional animal studies, both were shown to be well-tolerated when given in conjunction with either Flublok or Fluzone. 

One of the adjuvants, AF03, developed by Sanofi Pasteur, has also been shown to substantially improve humans’ immune responses to avian influenza vaccines.

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The other adjuvant, Advax-CpG55.2™ developed by Vaxine Pty Ltd, based in Adelaide, Australia is the most recent formulation of a sugar-based adjuvant that has been shown to increase the immune response elicited by vaccines for influenza in humans. 

NIAID supported the development of the Advax-CpG55.2™ combination through its Adjuvant Discovery and Development Program.

According to the Centers for Disease Control and Prevention (CDC), influenza vaccination can greatly reduce the risk of infection or severe influenza-related illness that may require hospitalization. 

Although seasonal influenza vaccines have been widely available for decades, their effectiveness varies from year to year, depending on how well the vaccine matches the disease-causing influenza virus strains that are circulating at that time, says the CDC.

When a person receives a vaccine containing an adjuvant, they are more likely to produce a stronger immune response to the vaccine, which may better protect them from the disease.

“As part of a comprehensive research effort to develop more effective and durable influenza vaccines, NIAID not only supports the development of new vaccines but also efforts to improve seasonal vaccines that are already available,” said NIAID Director Anthony S. Fauci, M.D., in a press release.

“We hope this trial will increase our understanding of how adjuvants could help confer better protection from seasonal influenza.”

Patricia Winokur, M.D., from the University of Iowa Carver College of Medicine in Iowa City, is the principal investigator of the trial, which is expected to last approximately 18 months.

When completed, the study will provide important safety and immunogenicity data on adjuvanted seasonal influenza vaccines. This information may help determine the best combination of vaccine and adjuvant needed to provide robust immunity, and ultimately improve the protection afforded by seasonal influenza vaccination.

NIAID conducts and supports research throughout the United States, and worldwide — to study the causes of infectious and immune-mediated diseases and to develop better means of preventing, diagnosing and treating these illnesses.