Influenza Surveillance and Risk Assessment

Understanding how influenza strains emerge, knowing where they are emerging and in which animal populations, and predicting how those strains may or may not affect humans are central to controlling and preparing for both seasonal influenza epidemics and potential influenza pandemics.

Centers of Excellence for Influenza Research and Surveillance

In 2007, NIAID created the Centers of Excellence for Influenza Research and Surveillance (CEIRS) to support U.S. and international researchers in the study of factors that control the emergence and transmission of flu viruses among animals and the immunological determinants of whether a flu virus causes only mild illness or results in severe illness or death in humans. The goal of the program is to provide federal and state governments with the public health tools and strategies necessary to control and lessen the impact of epidemic, seasonal influenza and potential influenza pandemics.

The CEIRS are currently based at:

  • Emory University, Atlanta
  • Icahn School of Medicine at Mount Sinai, New York City
  • Johns Hopkins University, Baltimore
  • St. Jude’s Research Hospital, Memphis, Tennessee
  • University of Rochester Medical Center, Rochester, New York

The CEIRS program continually monitors cases of animal and human influenza worldwide to rapidly detect and characterize viruses that may have pandemic potential, such as the avian influenza strains H5N1, H7N9 and H3N2v. For example, CEIRS-funded researchers monitor the evolution of H5N1 virus in southeast Asia, examine the prevalence of H5N1 virus exposure among poultry workers in Egypt, and study the incidence of influenza A virus among pigs at agricultural fairs in the United States.

Understanding Flu Infection through Challenge studies

Understanding how the human immune system responds to flu virus gives a better understanding of the basic biology of human flu infection and can yield important information for flu vaccine development. To learn more about this process, NIAID scientists at the NIH Clinical Center in Bethesda, Maryland, have conducted challenge studies, or clinical trials in which healthy volunteers are willingly exposed to naturally occurring flu virus. Information gained through these types of studies include how much time elapses between a known exposure to flu virus and the start of viral shedding (a sign of contagiousness), the onset and duration of flu symptoms, and the development of an immune response. These types of studies provide a scientific basis for more rapid, cost-effective clinical trials to evaluate new flu drugs or to determine the efficacy of candidate vaccines for both seasonal and pandemic flu. Recent data from these trials identified new, unexpected factors that may influence flu vaccine effectiveness.

Other NIAID-supported studies are examining how pre-existing immunity impacts the body’s response to flu infection or vaccination. Some studies focus on how this immunity develops and changes inchildren and young adults as compared to older adults. Scientists are also examining the impact of prior and/or repeated exposure to flu viruses on the immune response to vaccination or infection.

Content last reviewed on