The viruses involved in the fifth wave are also changing, she added. The number of cases of avian influenza A H7N9 is not only rising in humans but is involving a greater geographic spread. Viral genetic drift has also increased the need for new vaccine development, and a subset of viruses is now highly pathogenic in poultry.
Dr. Olsen shared data from a recent study
showing that just 3 amino acid mutations were needed to cause a switch in the specificity of avian influenza A H7N9 for human-type receptors. If these 3 mutations were to arise, they could potentially allow the avian virus to spread among humans with devastating effects. However, no evidence of human-to-human transmission of this virus currently exists, she added, which is encouraging.
Nevertheless, improved detection of this virus is critical, said Dr. Olsen, and risk assessment is important for pandemic preparedness. She highlighted CDC’s Influenza Risk Assessment Tool, developed to assess the potential pandemic risk posed by influenza A viruses that currently circulate in animals but not in humans.
According to Michael Osterholm, PhD, MPH, director, Center for Infectious Disease Research and Policy at the University of Minnesota, Minneapolis, another flu pandemic “is going to happen.”
But while this threat is inevitable, how ready are we in the United States for the next pandemic? “The bottom line message is—we’re not,” he emphasized. “We’re not prepared for another 1918-like pandemic.”
Although influenza vaccines will have some impact in protecting the population during a pandemic, Dr. Osterholm stressed that, on a global basis, this effect will be minimal.
Discussing why flu vaccines so often fail, he explained that many factors beyond antigenic match affect the level of protection that vaccines provide. These factors include when during the flu season a person receives a flu vaccine, whether they have previously received a flu vaccine, and which vaccine they received.
“We will have major challenges with the next flu pandemic without better vaccines for the world,” Dr. Osterholm said. Estimating the cost to bring forward a new flu vaccine at more than $1 billion, he highlighted the need for improved vaccines as an international priority. Achieving this will require major commitment and investment, he concluded.
Dr. Parry graduated from the University of Liverpool, England in 1997 and is a board-certified veterinary pathologist. After 13 years working in academia, she founded Midwest Veterinary Pathology, LLC where she now works as a private consultant. She is passionate about veterinary education and serves on the Indiana Veterinary Medical Association’s Continuing Education Committee. She regularly writes continuing education articles for veterinary organizations and journals and has also served on the American College of Veterinary Pathologists’ Examination Committee and Education Committee.
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