But the WHO has wrongly predicted which strain would be dominant six times in the past 11 years, GSK officials said, which resulted in formulations that did not provide the fullest protection to the public.
Vaccines with four strains are designed to increase the odds that the inoculation will be effective and not rely as much on the guesswork of scientists.
In some cases a new virus emerges for which there is no vaccine. The last time that happened was in 2009, with the emergence of the H1N1 flu virus. Seasonal vaccines now inoculate against the H1N1 strain.
The U.S. Centers for Disease Control and Prevention, in a 2012 study, said the benefits of 4-strain vaccines will depend on the number of people who are inoculated and on the virus strains in circulation. The agency said the benefits will likely be “modest” but noted that the use of 4-strain vaccines could prevent as many as 970,000 flu cases and up to 485 deaths in this country.
The vaccines are being shipped to doctors, health centers, businesses, health agencies, pharmacies, retailers and others that have placed orders.
The wholesale price for GSK’s 4-strain vaccines is about one-third higher than the cost of the traditional vaccine for three strains, said GSK spokesman Rob Perry.
GSK’s wholesale price to health care providers is $15.50 a dose for Fluarix Quadrivalent, which is delivered in prefilled syringes, and $14.15 for a dose of Flulaval Quadrivalent, which comes in vials. Perry said that the price can vary by the size of the order.