Thursday, March 01, 2012

Two B's Or Not Two B's? That Is the Question



Photo Credit- CDC PHIL


# 6187

. . . . that the FDA answered yesterday in the affirmative, in response to MedImmune’s request for approval for their quadrivalent flu vaccine containing both the Victoria and Yamagata strains of influenza B.


Until now trivalent formulations, containing two A strains and 1 B strain, have been the standard for seasonal influenza vaccines. 


But with two major lineages of influenza B in circulation around the world (Yamagata & Victoria), scientists have been forced to decide – 6 months in advance – which strain they believe will dominate in the coming flu season.


Some years they got it right.  Other years, not so much.


We’ve looked at the need for a quadrivalent vaccine before, in Attack Of The Killer `B’s and Two Bs Or Not Two Bs?.


Yesterday the FDA announced approval of a quadrivalent FluMist ® vaccine, suitable for those between the ages of 2 and 49.  


Here is the press release:




For Immediate Release: Feb. 29, 2012
Media Inquiries: Rita Chappelle, 301-796-4672,
Consumer Inquiries: 888-INFO-FDA


FDA approves first quadrivalent vaccine to prevent seasonal influenza

FluMist Quadrivalent, a vaccine to prevent seasonal influenza in people ages 2 years through 49 years, has been approved today by the U.S. Food and Drug Administration. FluMist Quadrivalent is the first influenza vaccine to contain four strains of the influenza virus, two influenza A strains and two influenza B strains.


Like the already approved FluMist (trivalent), the quadrivalent vaccine contains weakened forms of the virus strains and is administered as a spray into the nose.


There are two types of influenza viruses that cause illness and death in people: influenza A and B. Each year, the FDA-approved seasonal influenza vaccine includes three strains of influenza virus, two strains of influenza A and one of influenza B. During a typical influenza season, there may be two different influenza B strains circulating, or the B strain selected for inclusion in the trivalent influenza vaccine may not be the influenza B strain that eventually circulates causing illness. The inclusion of a second B strain in FluMist Quadrivalent increases the likelihood of adequate protection against circulating influenza B strains.


“Illness caused by Influenza B virus affects children, particularly young and school-aged, more than any other population,” said Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research. “A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts.”

(Continue . . . )



I’ve seen no official word yet on when this new quadrivalent vaccine will be made available to the public, or in what quantity.

No comments: