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

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Spring-Fall Flu Shots Safe, Protect Children

10/02/2004 DURHAM, N.C. - Giving flu vaccine to toddlers in the spring and fall guards against infection and is easier on parents than the fall schedule of two doses administered a month apart, found researchers from Duke University Medical Center and the University of Washington.

The study compared the immune response in toddlers aged six to 23 months who received a flu shot in the spring and one in the fall, to the response of those who received fall shots separated by one month. The Centers for Disease Control and Prevention this year issued a recommendation for flu vaccination for all children in this age group. Children given spring-fall shots - up to six months apart - were as well-protected as those who received two shots in the fall, the study showed. The spring-fall group also completed their immunization earlier than toddlers in the fall group. A survey of parents showed 66 percent preferred the spring-fall schedule.

The results were presented Oct. 2, 2004, at the annual meeting of the Infectious Diseases Society of America. The study was sponsored by an unrestricted grant from Aventis Pasteur, which manufactures flu vaccine.

"Kids less than two years old have a higher risk of significant complications from flu that require hospitalization. Trying to get them all in for their shots in fall is logistically tough and not necessarily convenient for parents. If we can get more kids immunized by making the schedule more convenient for parents, then we'll prevent more severe flu complications," said Emmanuel Walter, M.D., associate professor of pediatrics at Duke University Medical Center.

In the trial, the spring dose given during the study was the 2002-2003 vaccine and the fall dose was the 2003-2004 vaccine. Both vaccines coincidently had similar antigen components. Antigens are substances that stimulate an immune response. This year, the researchers will compare the immune protection afforded by the spring-fall schedule when the inactivated flu vaccine changes significantly from year to year. Toddlers enrolled in the study this spring received the 2003-2004 vaccine and will receive the 2004-2005 vaccine this fall.