NIAID-Funded Studies Seek to Evaluate Influenza Immunologic Imprinting in Children

Research has suggested that a child’s first encounter with an influenza virus or vaccine can influence how their immune system reacts to future exposures. The concept, referred to as immunologic imprinting, could provide valuable insight into creating protection against future infections with similar influenza subtypes.

This phenomenon may also have a negative influence on how an individual’s immune system reacts to a seasonal influenza vaccine. However, the concept of immunologic imprinting is still not fully understood.

In order to learn more about the imprinting, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has announced 2 financial awards to be used to study influenza immunity in children.

Investigators hope that by studying immune system responses to early influenza infection and future exposures that children encounter they will be able to pinpoint the underlying factors of immune responses. Understanding these factors could help with the development of more effective influenza vaccines.

The awards, which may total more than $64 million over the course of 7 years, will support studies led by Cincinnati Children’s Hospital Medical Center in Ohio and St. Jude Children’s Research Hospital in Memphis, Tennessee.

“NIAID is pleased to support these important observational studies of infants to broaden our understanding of how immunity to influenza develops and evolves over time,” NIAID Director Anthony S. Fauci, MD, said in making the announcement. “A comprehensive understanding of immunological imprinting will help inform the development of more broadly and durably protective influenza vaccines.”

A grant of up to $34.3 million over the course of 7 years will be awarded to a study led by principal investigators Paul Thomas, PhD, of St. Jude Children’s Research Hospital, and Aubree Gordon, PhD, of the University of Michigan School of Public Health. The study is designed to follow more than 3000 infants and young children in Los Angeles; Managua, Nicaragua; and Wellington, New Zealand, for 7 years.

A second grant will fund a study of more than 2000 infants and their mothers from Cincinnati and Mexico City for at least 3 years. The study will be led by principal investigator Mary A. Staat, MD, of Cincinnati Children’s, and will use weekly clinical visits to gather valuable data about the changes in the immune systems of the participants. This grant may total up to $29.9 million over 7 years.

Both of the studies will include the regular collection of nasal swabs and blood samples from the participants to learn more about B-cell and T-cell responses and function, the antibodies produced, and other changes as children are exposed to influenza viruses and vaccines.

The study teams hope that the investigations will determine how imprinting can be employed to boost the effectiveness of influenza vaccines, or how a new vaccine may provide broader immunity against influenza in a young child’s life.

According to NIAID, the research will also collect information that could be useful in developing a universal flu vaccine, which could provide protection against multiple influenza strains across all age groups.

“While these 2 long-term studies will focus on children, their results may eventually benefit people of all ages, as researchers use the findings to investigate vaccines that provide improved lifelong influenza immunity against different strains of the influenza virus,” the statement concludes.