Continuation of the H5N1 epornitic in the U.S. and the emergence of the infection in the dairy industry together with concerns expressed by the World Health Organization have focused attention on the need for vaccines in the event of an unlikely widespread infection among human populations in the world.
The Department of Health and Human Services has arranged for cell-based vaccine at CSL Seqirus to be prepared for bottling and distribution. This would make available five million doses for at-risk and critical personnel including workers on poultry and dairy farms, packing and processing plant workers, health care providers and those with the potential for exposure to the virus.
It is evident that in the remote event of a human pandemic, the time required to prepare a specific influenza vaccine in large quantities will be limited applying available egg propagation technology.
During the COVID crisis, the HSS Biomedical Advance Research and Development Authority (BARDA) funded development of novel vaccines. Based on the high cost of development and subsequent low demand for specialty vaccines including Ebola and Zika infections, confirmed orders by the public sector and subsidies were necessary to induce manufacturers to invest in production of COVID vaccines. Pfizer and Moderna have apparently destroyed millions of doses of expired mRNA COVID vaccines given a fall in demand.
At present, the manufacturers of traditional influenza vaccine are preparing for the fall 2024 combination. It is hoped that an H5N1 human vaccine is not required but if so, traditional egg-based manufacture will be unable to meet requirements.
Dr. Rick Bright who led BARDA and invested public funds in alternatives to egg propagation is now promoting cell-based alternatives despite the extensive investment in traditional fertile egg installations. Dr. Bright is correct in pointing to the problems encountered in 2009 with the emergence of H1N1 swine influenza that was responsible for extensive morbidity and mortality before effective specific vaccines could be prepared and distributed. He is, however, incorrect in implying that exposure of flocks of donor birds producing fertile eggs to prepare vaccines would be compromised for vaccine production in the event of exposure to HPAI. These SPF flocks are maintained under the highest levels of biosecurity, and it would be highly unlikely for a significant proportion to be exposed. Expanding egg production would, however, require time based on biological restraints to production. The development and application of mRNA influenza vaccines with broad specificity would appear to be the most desirable solution but only with up-front public sector support for manufacturers. Literally we are in a chicken-or-the egg situation.