Trial Underway of Nasal Spray Flu Vaccine

3-D print of influenza virus (National Institute of Allergy and Infectious Diseases, NIH)

23 June 2022. A clinical trial has begun testing an influenza vaccine given as a nasal spray with a conventional syringe-delivered vaccine among older U.S. adults. The study is conducted by the vaccine developer FluGen Inc., a biotechnology company in Madison, Wisconsin, and funded by a grant from the U.S. Department of Defense.

While the Covid-19 pandemic captured much of the public’s attention in the past three years, influenza or flu remains a public health concern, particularly for older populations. The flu virus has two main types, influenza A and B, with influenza A made up of combinations of 18 hemagglutinin proteins and 11 neuraminidase proteins, abbreviated to H and N. Because flu viruses mutate continually, called viral drift, the precise targets of H and N proteins are difficult to predict from year to year. And, vaccines need a long lead time for production, requiring those targets to be decided months in advance.

FluGen says it creates an influenza vaccine that addresses these issues. The FluGen technology uses a live engineered influenza virus with a part of a key gene called M2 removed. The full M2 gene is reconstructed only during production of the vaccine, which the company says limits the virus’s replication to just one time. FluGen says the M2 deleted, single-replication or M2SR live viruses, infect cells when given as a vaccine, but do not spread, yet still generate immune responses against the full range of influenza RNA and proteins. In addition, says the company, M2SR viruses generate immune responses in mucus membranes, antibodies, and cells.

Combinations of nasal spray, injection, or placebo

The early-stage clinical trial is enrolling 300 healthy participants, age 65 to 85, considered a vulnerable population to influenza, at four sites in the U.S., with the first of those individuals enrolled. Participants are randomly assigned to one of four groups receiving combinations of a FluGen nasal spray vaccine designed for the H3N2 flu virus that emerged in 2020 and conventional high-dose quadrivalent flu vaccine, or nasal spray and vaccine placebos.

The study team is looking primarily for signs of adverse effects in the first seven days after receiving vaccines and/or placebos, then for the next three weeks, particularly serious adverse effects. The company says participants are also assessed for their immune responses during this time, including production of anti-viral T-cells.

FluGen is spun-off from research labs at University of Wisconsin veterinary medicine school in Madison, founded in 2007. In Sept. 2018, Science & Enterprise reported on an earlier clinical trial of the company’s technology with children and teens, sponsored by National Institute of Allergy and Infectious Diseases.

“We have seen numerous approaches to solving the challenge of influenza vaccine efficacy over the past decade,” says Yoshihiro Kawaoka, professor of virology at UW-Madison and a co-founder of FluGen in a company statement, “but despite these efforts, none have achieved the efficacy needed to improve health outcomes. This study is important, as it is the first of its kind to combine intranasal vaccine delivery with intramuscular shots to determine the potential for boosting vaccine efficacy and reducing transmission and virus shedding.”

More from Science & Enterprise:

• Lung Chip Reveals Respiratory Immune Responses
• Trial Set for Respiratory Disease Nasal Spray Vaccine
• Univ. Lab Licenses Protein for Vaccine Patch
• Covid-19 Nasal Spray Vaccine Trial Underway
• Crispr Enables Inhaled Flu, Covid-19 Treatment

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