U.S. orders 4.8 million doses of a cell-based, adjuvanted H5-vaccine for avian flu preparedness

Influenza vaccine producer CSL Seqirus has been selected by the U.S. government to complete the fill and finish process for a “pre-pandemic vaccine that is well-matched to the H5 of the currently circulating H5N1 strain,” according to a May 30 press release from the company about the agreement.

CSL Seqirus will deliver approximately 4.8 million doses of the vaccine as part of the National Pre-Pandemic Influenza Vaccine Stockpile program. The company’s manufacturing facility in Holly Springs, North Carolina — built through a partnership established in 2019 with the Biomedical Advanced Research and Development Authority, part of the U.S. Department of Health and Human Services — “is the largest cell-based influenza vaccine producer in the world and is the first such domestic facility,” the release said.  

Also on May 30, an MMWR article noted that the Administration for Strategic Preparedness and Response at HHS is supporting the clinical evaluation of the safety and immunogenicity of an influenza A/Astrakhan/3212/2020–like virus vaccine. “The clinical study (NCT05874713) testing cell-based antigen combined with MF59 adjuvant … has completed enrollment,” according to the article.

The official title of this fully enrolled CSL Seqirus study is “A Phase 2, Multi-Center, Randomized, Observer-Blind Study, to Evaluate Safety and Immunogenicity of Homologous or Heterologous Priming and Booster Vaccinations With H5N8 or H5N6 MF59-adjuvanted, Cell Culture-derived Influenza Vaccine in Healthy Subjects ≥18 Years of Age.”

Proactive and effective communication by the U.S. government with the public, health care providers, public health workers, journalists, politicians and others about the rationale for why this first candidate vaccine — using the Astrakhan H5 antigen, the MF59 adjuvant and cell-based (rather than egg-based) production — was chosen will be important.