U.K. regulators have extended the suspension of Chiron Corp.‘s influenza vaccine production in Liverpool, England, for another three months from Jan. 4, the company said on Tuesday.

Regulators in the United States have been seeking overseas sources of flu vaccine after losing almost half the country’s anticipated supply in October, when Chiron, one of two major makers, lost the license for its British plant because of contamination problems.

The Emeryville, Calif. company said on Tuesday that the Medicines and Healthcare Products Regulatory Agency (MHRA) has notified it that the latest suspension is not a result of new safety issues at the Liverpool plant.

The agency called the suspension a routine regulatory action that will give the company more time to carry out its ongoing remediation plan, Chiron said.

Chiron said the agency notified it that the suspension could be lifted at any time upon satisfactory compliance with the facility’s license.

The MHRA has worked closely with the U.S. Food and Drug Administration on these issues, and the agencies plan to examine progress at the facility throughout the remediation process, Chiron said.

In order to meet timelines for delivery of Fluvirin influenza virus vaccine for the U.S. market, production must begin no later than early spring of 2005.

The MHRA notice fulfills an agency requirement to allow Chiron a 28-day period to appeal the notice, but Chiron does not intend to pursue this option, it said.