LOS ANGELES—Pediatricians have observed that a baby’s early infection with flu impacts their later response to the virus, as well as how protected they are by vaccination. To better understand how this immunological imprinting occurs, the National Institute of Allergy and Infectious Diseases has awarded Children’s Hospital Los Angeles $3 million to study 450 newborns who will be enrolled over a three-year period. Researchers will follow the children for 7 years to learn how their immune systems develop in response to both flu vaccination and infection.
Influenza viruses are constantly mutating, so new versions of the vaccine need to be developed each year. In spite of these attempts to optimize the vaccine, there are still variables affecting how well it protects against infection. The vaccine is developed against strains of flu that researchers expect will circulate in the community that year. Some years the match is good and the vaccine protects most people who are immunized, but in other years, the match isn’t as optimal.
Although the annual changes occurring to the viruses are small, they are seen as significant by the immune system. That’s why in spite of being immunized or having had the flu in previous years, people may not produce the optimal immune response and may still be susceptible to the viruses. There are also immunological differences in people who receive the vaccine that can affect how well they are protected.
“A child’s first exposure to the flu virus produces the most impactful and long-lasting immunological response,” said Pia Pannaraj, M.D., MPH, who will lead the CHLA portion of the study. “That initial exposure sets the bar for a lifetime of immunological responses to influenza.” The strains of flu experienced during this first exposure will confer a lifelong immunologic imprint that impacts the ability to respond to future strains of the virus that may be slightly different.
Can the right initial exposure be used to provide lifelong protection against the flu, or boost the effectiveness of future flu vaccines? Pannaraj explained that these are some of the questions the study seeks to answer. This knowledge will help move investigators closer to their goal of developing a universal vaccine that can protect people of all ages against multiple strains of influenza, including strains of the next pandemic.
In the meantime, the study allows Pannaraj to continue her research to maximize vaccines’ effectiveness, and she said she looks forward to the study providing new insights on ways to better protect young children against flu.
The multicenter study team will receive a total award of $35 million and is being led by St. Jude Children’s Research Hospital in Memphis, Tennessee, and the University of Michigan School of Public Health. Laboratory analyses will be conducted at multiple sites. Children’s Hospital Los Angeles is the only enrolling site in the U. S.; additional infant cohorts will be followed in Nicaragua and New Zealand.
