Flu Vaccine Effective for Kids

Influenza vaccine works in children under five years old in new study

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) No vaccine is completely effective, so it's helpful to understand how effective different vaccines are when people decide whether to get vaccinated. Until now, there has been little information about the flu vaccine's effectiveness for children.

A new study found that the flu vaccine is effective in children under 5 years old and particularly for children under 2 years old.

The flu vaccine is recommended for all children aged 6 months and older by the Advisory Committee on Immunization Practices at the US Centers for Disease Control and Prevention.

Children getting the flu vaccine for the first time are recommended to receive two doses, at least a month apart, to receive as much protection as possible against the flu.

"Ask your doctor about the flu vaccine."

The study, led by Christopher C. Blyth, MBBS, of the School of Pediatrics and Child Health at the University of Western Australia, evaluated how effective the flu vaccine is in young children.

The researchers began the study in 2008, tracking 2,001 children, aged 6 months to 4 years old, through 2012.

The researchers determined who had received the trivalent flu vaccine by asking parents and then confirming with vaccination or medical records. Children who became ill were tested for the flu.

The researchers compared who had received the flu vaccine to those who hadn't across three groups: those who got the flu, those who didn't get the flu, and those who became ill with a different virus besides the flu.

In doing their analyses, the researchers adjusted their calculations to account for differences in the months the children became ill, whether the children had been born premature or not, whether the children were indigenous (Aborigine) or not, and the children's age, sex and other health conditions.

About a quarter of the children had received at least one flu vaccine, with 16 percent overall who were fully vaccinated against the flu and 8 percent who were partially vaccinated.

One-fifth of the children (389 children, or 20 percent) tested positive for the flu, and another 60 percent were diagnosed with another respiratory virus that wasn't the flu.

When the researchers compared the children who had been vaccinated (partially or fully) with those who had not, they found that the vaccine's effectiveness varied across the years studied.

Overall for the full period studied, the average effectiveness of the flu vaccine was 65 percent.

That means that getting the flu vaccine reduced children's chances of catching the flu by 65 percent.

Among children under 2 years old, the vaccine was 86 percent effective.

"Influenza vaccination in children under 2 years has been a contentious issue due to the paucity of data showing vaccine effectiveness," the authors wrote.

"Our findings reveal the effectiveness of the trivalent influenza vaccine in healthy young children, including those younger than 2 years of age and support the current ACIP recommendations for young children," they wrote.

ACIP stands for the Advisory Committee on Immunization Practices, the group at the US Centers for Disease Control and Prevention that makes vaccine recommendations.

The study was published April 21 in the journal Pediatrics. The research was funded by the Western Australia Department of Health, and the flu vaccine used in the study were provided by the companies Sanofi-Pasteur and CSL Biotherapies.

Four authors are members of the Vaccine Trials Group, which has received funding from vaccine manufacturers to conduct clinical trials not related to this study.

One of these authors, Peter Richmond, has also served on a CSL Ltd scientific advisory board regarding flu vaccines, received travel funds from Baxter and GlaxoSmithKline, and received research funding from GlaxoSmithKline and CSL Ltd.

A fifth author is director of the Asia-Pacific Alliance for the Control of Influenza and previously the Australian Influenza Specialist Group, both independent, not-for-profit groups that have received funding from pharmaceutical companies. No other possible conflicts of interest were reported.

Review Date: 
April 21, 2014
Last Updated:
January 12, 2015