CSL starts U.S. swine flu vaccine trial

A syringe extracts an experimental H1N1 swine flu vaccine from a vial before being administered to a medical volunteer during early trials with medical volunteers at the University of Maryland in Baltimore, August 10, 2009. REUTERS/Jason Reed

WASHINGTON (Reuters) - CSL Ltd started testing its swine flu vaccine on U.S. children and adults on Monday, joining other companies testing the H1N1 vaccine as they also step up production.

The Australian-based company said it would test 1,300 adults and 450 children with different doses of its vaccine to help determine what the best dose will be.

“Children are often at greater risk from influenza infection and its complications than adults, so it is extremely important to understand the efficacy of an H1N1 vaccine in this very vulnerable population,” Dr. Pedro Piedra of Baylor College of Medicine in Texas, who will help conduct the trial, said in a statement.

“The clinical trials of CSL’s candidate vaccine will be the first to use a thimerosal-free formulation of the H1N1 vaccine antigen.”

Some people object to the use of thimerosal, which is a mercury-based preservative. U.S. health officials say there is no evidence to support persistent beliefs that thimerosal causes autism, but companies have removed it from most vaccines anyway.

Last week, the U.S. Department of Health and Human Services said only 45 million doses of the new H1N1 vaccine would be on hand in mid-October, instead of 120 million previously forecast, with 20 million a week due after that.

HHS plans to eventually vaccinate at least 160 million people by December, with pregnant women, health-care workers, children and young adults at the front of the line.

Five companies are making the H1N1 vaccine for the U.S. market -- AstraZeneca’s MedImmune unit, CSL, GlaxoSmithKline Plc, Novartis AG and Sanofi-Aventis SA. Sanofi has also started trials in the United States and several companies, including Glaxo, have trials ongoing in Europe.

Editing by Maureen Bavdek