British authorities have extended the suspension of Chiron’s manufacturing license from January to April, again jeopardizing the company’s ability to send flu vaccinations to the U.S. As a result, other manufacturers are considering taking over the production themselves.

Chiron officials, however, said they remain optimistic that their company is still capable of producing 2005-2006 U.S. flu vaccinations. The creation of flu vaccine doses takes many months and starts in the spring each year.

Contamination issues led British Medicines and Healthcare Products Regulatory Agency to suspend the manufacturing license for Chiron’s Liverpool plant this fall, shorting the U.S. of half its expected flu vaccine supply this flu season.

Officials with French-based Aventis Pasteur, the company providing the U.S. with 58 million flu doses during the shortage, said they could increase its U.S. market production to 60 million doses for the 2005 flu season. GlaxoSmithKline, another source of this year’s supply, also has the potential to earn a permanent U.S. license, according to healthcare analysts and officials.