Spring-Fall Flu Shots Tested for Kids

Background: It is recommended that toddlers less than 2 years of age be given two doses of the flu vaccine because this age group does not develop a sufficient immune response to a single dose. Young children usually receive the two flu shots a month apart in the fall. But, alternatively, kids can also be given one flu shot in the spring and the second one in the fall. But is this time frame as safe and effective as the usual one?

Study: A group of young children were given one spring dose of the flu vaccine and one fall dose. They were characterized as the spring-fall group and following this time frame, they completed their shots by October 2. The children who were in the fall-fall group finished their flu shots by December 2. The children in the spring-fall group were as protected from the flu as the children in the fall-fall group.

Comment: In this flu vaccine trial, the spring dose was the 2002-2003 vaccine and the fall dose was the 2003-2004 vaccine, meaning that both vaccines had similar antigen components. Since the formulation of the flu vaccine normally changes from year to year, the study is being repeated with the spring 2003-2004 vaccine and the new fall 2004-2005 vaccine.

Practitioners are urged not to adopt the spring-fall vaccination time frame until the study has been repeated during a year when there is greater difference between the flu vaccines. It should be also be emphasized that the study at Duke University Medical Center (and the University of Washington) was funded by Aventis Pasteur, maker of the flu vaccine.

Barbara K. Hecht, Ph.D.
Frederick Hecht, M.D.
Medical Editors, MedicineNet.com