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FDA panel recommends flu vaccine changes for 2006/07
Fri Feb 17, 2006 6:00 PM ET
http://today.reuters.com/news/newsArticle.aspx?type=healthNews&storyID=2006-02-17T225959Z_01_N17187894_RTRUKOC_0_US-FLU.xml
By Todd Zwillich
BETHESDA, Maryland (Reuters) - A U.S. Food and Drug Administration advisory panel on Friday recommended changing two of the three virus strains used in this year's seasonal flu vaccine for the 2006/07 flu season.
Experts on the panel voted unanimously to replace two of this year's strains because of surveillance data showing shifts in the activity of viruses circulating in Europe and Asia.
They stressed that their recommendations represent a "best guess" of what viruses will affect the United States in the 2006-2007 flu season. "Influenza viruses are inherently unpredictable," Nancy Cox, chief of the influenza branch at the Centers for Disease Control and Prevention, told the panel.
The seasonal flu vaccine is known as a "trivalent" vaccine because it contains three different virus strains. Each of the strains is chosen for their ability to inhibit infection with dozens of different but closely related viruses.
Viruses shift their potency and frequency each flu season. Manufacturers alter the vaccine's makeup each year to maximize the chances that it will effectively protect humans.
Influenza causes an estimated 200,000 hospitalizations and 36,000 deaths per year in the United States, according to the CDC.
The vast majority of cases are caused by Influenza A viruses.
The FDA advisory panel voted to change the current vaccine's "California" strain of the H3N2 Influenza A virus to a different H3N2 strain known as a "Wisconsin" strain. Experts also recommended a shift from the less common "Shanghai" Influenza B strain to a different B strain known as "Malaysia/2506."
The panel recommended no change to the current vaccine's "New Caledonia" strain of the H1N1 Influenza A virus.
The vaccine recommendations match others issued by the World Health Organization earlier this week.
Manufacturers typically hope for few changes in the vaccine. Changes mean more uncertainty in production, because different strains grow at different rates during the manufacturing process.
"Obviously it is a concern," said Albert Thomas, director of vaccine manufacturing for Sanofi-Pasteur, the largest U.S. vaccine maker and a unit of French company Sanofi-Aventis. "It does put more uncertainty into the total number of doses you're producing at any one time," he told the panel.
But Kathleen Coelingh, senior director for scientific affairs for FluMist manufacturer MedImmune Inc., said there were few surprises in Friday's recommendation. "Everyone has been expecting this to happen based on the epidemiology we've been seeing," Coelingh said in an interview.
Less than 1 percent of all U.S. flu cases this year were caused by Influenza B viruses. But experts are still considering the possibility of recommending a "quadrivalent, or four-strain, vaccine in the future that contains two types of Influenza B virus.
That possibility has occupied expert vaccine panels for years, and Friday's committee recommended that the FDA convene a new committee to discuss scientific data justifying the manufacture of a four-strain vaccine.
Fri Feb 17, 2006 6:00 PM ET
http://today.reuters.com/news/newsArticle.aspx?type=healthNews&storyID=2006-02-17T225959Z_01_N17187894_RTRUKOC_0_US-FLU.xml
By Todd Zwillich
BETHESDA, Maryland (Reuters) - A U.S. Food and Drug Administration advisory panel on Friday recommended changing two of the three virus strains used in this year's seasonal flu vaccine for the 2006/07 flu season.
Experts on the panel voted unanimously to replace two of this year's strains because of surveillance data showing shifts in the activity of viruses circulating in Europe and Asia.
They stressed that their recommendations represent a "best guess" of what viruses will affect the United States in the 2006-2007 flu season. "Influenza viruses are inherently unpredictable," Nancy Cox, chief of the influenza branch at the Centers for Disease Control and Prevention, told the panel.
The seasonal flu vaccine is known as a "trivalent" vaccine because it contains three different virus strains. Each of the strains is chosen for their ability to inhibit infection with dozens of different but closely related viruses.
Viruses shift their potency and frequency each flu season. Manufacturers alter the vaccine's makeup each year to maximize the chances that it will effectively protect humans.
Influenza causes an estimated 200,000 hospitalizations and 36,000 deaths per year in the United States, according to the CDC.
The vast majority of cases are caused by Influenza A viruses.
The FDA advisory panel voted to change the current vaccine's "California" strain of the H3N2 Influenza A virus to a different H3N2 strain known as a "Wisconsin" strain. Experts also recommended a shift from the less common "Shanghai" Influenza B strain to a different B strain known as "Malaysia/2506."
The panel recommended no change to the current vaccine's "New Caledonia" strain of the H1N1 Influenza A virus.
The vaccine recommendations match others issued by the World Health Organization earlier this week.
Manufacturers typically hope for few changes in the vaccine. Changes mean more uncertainty in production, because different strains grow at different rates during the manufacturing process.
"Obviously it is a concern," said Albert Thomas, director of vaccine manufacturing for Sanofi-Pasteur, the largest U.S. vaccine maker and a unit of French company Sanofi-Aventis. "It does put more uncertainty into the total number of doses you're producing at any one time," he told the panel.
But Kathleen Coelingh, senior director for scientific affairs for FluMist manufacturer MedImmune Inc., said there were few surprises in Friday's recommendation. "Everyone has been expecting this to happen based on the epidemiology we've been seeing," Coelingh said in an interview.
Less than 1 percent of all U.S. flu cases this year were caused by Influenza B viruses. But experts are still considering the possibility of recommending a "quadrivalent, or four-strain, vaccine in the future that contains two types of Influenza B virus.
That possibility has occupied expert vaccine panels for years, and Friday's committee recommended that the FDA convene a new committee to discuss scientific data justifying the manufacture of a four-strain vaccine.