Scientists from the University of Missouri School of Medicine have used a natural protein to develop an influenza vaccine that could prevent babies under 6 months old from contracting the flu.
Millions of people become seriously ill from influenza every year, and the World Health Organization reports the flu annually causes between 250,000 and 500,000 deaths. Unfortunately, the people most at risk for contract the flu are the ones who cannot have vaccines – infants who are under 6 months old.
"Influenza vaccine works by stimulating a person's immune system to make antibodies that attack the flu virus," Dr. Michael Sherman, professor emeritus in the Department of Child Health at the Missouri School of Medicine and lead author of the study, said. "However, infants younger than 6 months do not make antibodies when given flu vaccine. This is because the immune systems of these very young babies do not respond to the adjuvant, or additive, within the vaccine that boosts the body's immune response when confronted with a virus."
The added protein for most vaccines is known as aluminum hydroxide (ALUM). This additive aggravates white blood cells (known as neutrophils) to the vaccinated infection, provoking an immune response. This additive does not work in infants because of their immature cells.
"It is well-documented that infants obtain protection against certain infections from nutrients found in breast milk," Sherman said. "Lactoferrin is the major protein in a mother's milk and boosts her infant's immune system to fight infection. In theory, we felt that we could create a vaccine by replacing ALUM with lactoferrin as an additive."
To resolve this problem, the researchers added lactoferrin to the influenza vaccines, creating a vaccine that may be effective and safe for infants.
"Currently, the best protection for neonatal babies is to vaccinate the mother and all those who will have close contact with the infant," Sherman said. "Our recent study was meant to test the possibility of creating a safe and effective flu vaccine for very high-risk premature infants. Now that we have, we feel that the use of a natural protein would make immunization not only possible but more accepted."