Study To Test Seasonal Flu Vaccines with Two Adjuvants

An early-stage clinical trial is evaluating two licensed seasonal influenza vaccines, administered with or without novel adjuvants, for their safety and ability to generate an immune response. Adjuvants are compounds added to vaccines to induce stronger and longer-lasting immune responses.

The phase 1 study is enrolling healthy adult volunteers at eight sites across the United States. The trial is funded by NIAID.

According to the Centers for Disease Control and Prevention, 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. When people receive 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 Dr. Anthony Fauci. “We hope this trial will increase our understanding of how adjuvants could help confer better protection from seasonal influenza.”

The trial will enroll 240 healthy volunteers ages 18 to 45 years at 8 vaccine and treatment evaluation units—a network of clinical trial sites funded by NIAID. Dr. Patricia Winokur of the University of Iowa Carver College of Medicine is principal investigator of the trial, which is expected to last approximately 18 months.

Volunteers will be randomly assigned to receive one dose of either the Fluzone quadrivalent influenza vaccine or Flublok quadrivalent influenza vaccine. The vaccine will be given alone or in combination with either the AF03 or the Advax-CpG55.2 adjuvant. 

Fluzone and Flublok are manufactured by Sanofi Pasteur, the vaccines global business unit of Sanofi, and are reformulated each year to best match the anticipated seasonal influenza strains selected by the World Health Organization.

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.