Flu vaccines are effective in preventing the illness in children older than two years, according to a new report.

However, the researchers stressed that large studies are still needed to see whether the shots actually help reduce serious complications associated with the flu before immunization in children can be recommended as public health policy.

Writing in the February 26th issue of the medical journal The Lancet, Dr. Tom Jefferson, from Cochrane Vaccines Field in Alessandria, Italy, and his colleagues noted that their findings were based on an analysis of 24 earlier studies.

Flu vaccines appeared to reduce long school absences by 86% compared with placebo vaccines, or “dummy” shots, according to the researchers. There was no evidence that the shots helped prevent complications like lower-respiratory tract disease or the need for hospitalization, but better and larger studies are needed to know for sure, they said.

“Although a growing body of evidence shows the effect of influenza on (hospital) admissions and deaths of children, we recorded no convincing evidence that vaccines can reduce mortality, admissions, serious complications, and community transmission of influenza,” the authors concluded.

Live attenuated vaccines were more effective than inactivated vaccines in children, the researchers noted. In children older than two years, the former had 79% efficacy, while the latter had 65% efficacy.

In children younger than two years, inactivated vaccines performed about the same as placebo.

SOURCE: The Lancet, February 26, 2005.