April 26 (Reuters) - The U.N. World Health Organization and U.S. Centers for Disease Control and Prevention have been collecting samples of the new H1N1 swine flu virus to make a new vaccine in case it is needed. Following are some facts about influenza vaccines. * The WHO and CDC prepare samples of virus to give to industrial makers. * These samples must be grown in specially produced chicken eggs. The virus is then purified and made into vaccines, a process that takes months. * At least 20 companies make flu vaccines including Sanofi Pasteur <SASY.PA>, Australia's CSL Ltd <CSL.AX>, GlaxoSmithKline Plc <GSK.L>, Novartis AG <NOVN.VX>, Baxter <BAX.N> and nasal spray maker MedImmune, acquired by AstraZeneca Plc <AZN.L>. * Experts agree the current process for making vaccines is clumsy and outdated, but new and more efficient technologies are still a few years away. * WHO and CDC experts are trying to decide if a new vaccine for the H1N1 swine flu strain is needed, or perhaps if a fourth element could be added to the seasonal flu vaccine mix for next September. * The health agencies also had been considering adding some vaccines against H5N1 avian influenza, which occasionally infects people and is also considered a major pandemic threat. * Tests show the H1N1 component of the current seasonal flu vaccine does not protect against the new strain. * Consulting firm Oliver Wyman found that drug companies would need four years to meet global demand for vaccines if a pandemic broke out today, but new technology could significantly boost production by 2014. * Currently, drug makers could make up to 2.5 billion doses of pandemic vaccines in one year, meaning it would take four years to meet global demand, Oliver Wyman found. In a best-case scenario, they could make 7.7 billion doses in 1.5 years. * Compounds called adjuvants can be used to boost a vaccine's effectiveness, so it could be diluted and used in more people. * Current global demand for seasonal influenza vaccine is about 500 million doses a year. * The CDC recommends that 261 million Americans -- 85 percent of the population -- should be vaccinated against flu. A RAND Corp. study in December showed that only about a third of those who should have did get the vaccine. (Reporting by Maggie Fox; Editing by Will Dunham)
A biohazard sign on a sample box is seen at the County of San Diego Health and Services Agency in San Diego, California April 26, 2009. The United States declared a ...
