On Wednesday U. S. health officials approved a high-dose influenza vaccine for people aged 65 years and more. The vaccination is made by Sanofi-Aventis DA (SASY. PA).

The Food and Drug Administration said that the immune system becomes stronger with a higher dose that protects aged people better against seasonal flu.

Sanofi Pasteur, the company's vaccine unit, informing about the availability of the vaccine said that the vaccine will be available in the fall of 2010 ahead of the next flu season.

Comparing the high dose with Sanofi's regular-dose Fluzone the FDA said redness and injection-site swelling were more frequent with the high dose vaccine but termed it non-serious.

During a trial in which the high-dose vaccine was compared with standard-dose influenza vaccine conducted on 3,876 adults aged 65 years and more it was concluded that the new high-dose vaccine bought a significant increases in immune responses compared with the standard-dose vaccine.

During the trial however the most common injection site reactions (.10%) were injection site pain and redness. The most common systemic adverse events (.10%) were headache, malaise and myalgia.