Shielding against pandemic flu dangers

Birmingham-based Southern Research conducts tests on emerging pandemic strains and participates in strategic government vaccine programs focusing on highly pathogenic avian influenza (HPAI) strains that pose potentially grave public health risks.

In addition, Southern Research has performed toxicology studies for flu vaccine platforms and provided pre-clinical studies on vaccine candidates, along with clinical trial support for vaccine makers. The non-profit organization has also researched antiviral treatment approaches that could protect people after infection.

"Scientists will tell you it's not if, it's when we have a pandemic. That's the way the flu virus works," said Landon Westfall, Ph.D., a senior project manager and infectious disease scientist at Southern Research. "It's like the San Andreas fault -- the big one is coming one day. The idea is since we can't prevent it, we should prepare for it. That's the goal."

Pandemic influenza strains pose much a greater threat than even the nastiest strains of seasonal flu. The dominant seasonal strain this year, H3N2*, fits that description, causing an above-average rate of hospitalizations and prompting Alabama to declare a public health emergency.

The current flu season's misery is worsened by the fact that the available vaccine is only moderately effective.

"That's the challenge with flu. Vaccines don't always work," Westfall said. "Most of the time, they protect 55 to 60 percent of the population. That's kind of the goal of influenza vaccines. But there will always be subsets of the population that won't be protected."

Elevated Dangers

Novel avian or swine flu strains, however, have the potential to cause lethal damage on a global scale. Because these dreaded strains are new, very few people have immunity against them, so they can spread widely and rapidly, sickening a large segment of the population, Westfall said.

When pandemics emerge, more than half of an affected population can be infected in a single year, while the number of deaths stemming from the flu outbreak can sharply exceed normal levels.

That's why the work being conducted by Southern Research and other organizations as part of the U.S. government's influenza preparedness programs is critically important, Westfall said.

The goal is to prevent a global calamity like the 1918 Spanish flu pandemic, which killed more than 50 million people, and outbreaks in 1957 and 1968 that each killed at least 1 million people worldwide. The last pandemic, the 2009 H1N1 swine flu outbreak, killed as many as 575,000 people.

For more than a decade, pandemic fears have centered on the highly lethal H5N1 avian influenza, despite the fact that the so-called "bird flu" virus does not infect humans easily. If a mutated form of the H5N1 virus became easily transmissible from person to person while retaining its severe effects, the public health consequences could be very serious, the World Health Organization warns.

"For the most part, avian influenza affects birds. When the virus makes a jump for one species to another, say from bird to human, that's a big thing," said Westfall, who oversees the influenza virology program for Southern Research's Drug Development division. "That's a rapid evolution for a virus that will likely cause major problems. In cases, where the avian flu has infected humans, the mortality rate has been around 60 percent."

Southern Research scientists have worked on influenza projects for government agencies including the National Institutes of Health, the National Institute of Allergies and Infectious Diseases, and the Biomedical Advanced Research and Development Authority. The organization has also worked with a number of commercial clients.

"We're recognized as one of the leading supporters for clinical vaccine research, especially for flu," Westfall said. "That is partly because of our history in the field but also because of our capabilities to test a large volume of samples in a relatively short time."

Pandemic

Although most experts believe another influenza pandemic is inevitable, Westfall said it is impossible to predict when or where it will occur, or how severe its impact will be. It's almost impossible to predict with certainty the subtype of influenza virus most likely to cause the next worldwide outbreak.

Late in 2017, scientists reported that a new strain of H7N9 avian flu circulating in China showed the ability to transmit easily among animals with highly lethal results, raising alarm about its potential to trigger a global human pandemic.

While the Centers for Disease Control and Prevention says the risk of H7N9 is currently low because human-to-human transmission is rare, the CDC still rates the strain as having the greatest potential to cause a pandemic.

Westfall said the evolving nature of influenza viruses presents tough challenges to the research community.

"Flu is like a malleable pathogen that can change from week to week, from month to month, and from region to region," he said. "Every person who gets infected with the flu basically creates a small change in that virus that's then passed on to multiple people. Flu constantly changes that way."

*In the designation of influenza subtypes, the H refers to hemagglutinin, a protein found on the surface of flu viruses, while the N refers to viral neuraminidase, another protein present on the surface of the virus.