Influenza accounts for 33-50,000 deaths annually in the United States, and half a million deaths worldwide. Every year, the virus evolves rapidly, infection numbers surge, and new ways to combat the spread must be devised.

It’s a race that researchers have been running for over a century; trying to develop a vaccine that is effective beyond this year’s generation of the virus, while predicting the ways in which the virus may evolve in the future.

“A vaccine that we use this year may not be very protective next year, so we’re constantly playing this game of chase,” said Pejman Rohani, Regents’ Professor and UGA Athletic Association Professor in the Odum School of Ecology.

Rohani and colleague John Drake, Regents’ Professor and director of the Center for the Ecology of Infectious Diseases, help to develop computational models for forecasting the spread of influenza. They work with researchers from across the world, from Australia to South America, under the umbrella of the Center for Influenza Disease and Emergence Research (CIDER).

“Influenza pandemics are amongst the most serious global threats to human health,” said Mark Hunter, dean of the Odum School of Ecology. “The research that Dr. Rohani and colleagues lead will help us to better predict and prepare for future influenza outbreaks.”

CIDER is one of six Centers of Excellence for Influenza Research and Response in the U.S.—a network of researchers that collaborate across disciplines to better understand influenza and its effects. CIDER was established in 2021 with a $1 million award from the National Institute of Allergy and Infectious Diseases, and since 2021, it has received more than $13 million based on approval of 20 contract options. The center began with seven lead investigators at seven institutions in the U.S., Australia and Colombia; it has grown to include 14 lead investigators with projects at more than a dozen institutions in the U.S., South America, Europe and Australia.

In order to advance its mission, CIDER maintains a robust international network of surveillance and research sites. The Pediatric Intensive Care Influenza Cohort, based at Boston Children’s Hospital, samples patients under 21 years of age who have been affected severely by influenza to try to understand how the disease came about, as well as offering valuable data as part of an ongoing pandemic response plan.

The University of Melbourne houses two cohorts: Dissection of Influenza-Specific Immunity, which collects data on patients hospitalized with influenza in Australia, and Looking into Influenza T Cell Immunity. LIFT collects data on adult indigenous Australians, a population with a high risk of influenza.

The Immune Responses in Indigenous Vaccine-naïve Populations cohort works with multiple tribes on the coast of Colombia. These populations provide a unique chance to observe the effects of vaccination, influenza and other respiratory diseases on an unvaccinated population.

At UGA, CIDER is directed by Mark Tompkins at the College of Veterinary Medicine, with Rohani serving as deputy director. CIDER supports several projects with faculty in the Odum School and the College of Public Health, with a focus on establishing models to define features of influenza- and vaccine-elicited immunity, as well as virus transmission and evolution. Rohani’s project focuses on influenza B, a less understood and less common type of flu that only affects human populations, as well as avian influenza, also known as H5N1 bird flu.

In what has been a year of firsts for avian influenza, an outbreak in dairy cattle has shifted more of the network’s focus to prevention and forecasting. Cattle in 14 states have contracted H5N1 bird flu, the first time the virus has ever been discovered in cows. In April 2024, a person in contact with dairy cows in Texas was infected with H5N1, also thought to be the first recorded instance of the virus spreading from non-human mammal to human.

Three hundred and thirty herds of cattle have now been affected by the virus. There is currently no evidence of human-to-human transmission.

But that may not always be the case.

With flu season underway, researchers fear that the newly minted strain of H5N1 may undergo what is called a genetic exchange event, in which two types of flu virus in close proximity swap sections of their genetic code. Such an event would alter the strain in rapid and unpredictable ways.

If a human host who is infected with the common flu also becomes infected with the new H5N1 strain, they could possibly become a patient zero for another pandemic, as a new virus literally builds itself within them.

“You could have a new kind of virus emerge that’s got the genes that make it transmissible between humans, and the genes that make it nasty from the virus that’s infecting cattle,” Rohani said.

He and his CIDER colleagues are working hard to prevent that kind of outcome.

“We would be very worried about another pandemic if the virus became transmissible between humans.”