EPIDEMIC STRAINS of influenza viruses now are being identified—because of improved surveillance in Asia, especially China—as early as 2 years before they are expected to emerge as major causes of disease in the United States.
Helen Regnery, PhD, Influenza Branch, Centers for Disease Control and Prevention (CDC), Atlanta, Ga, says that this early identification and tracking of flu strains is allowing the US scientific community time to prepare effective vaccines. Thus, she says, in recent years the strains incorporated into these vaccines have matched very accurately with the strains involved in the subsequent influenza outbreaks.
The longtime problem of course has been that, in selecting suitable strains in February or March to manufacture a vaccine that will be effective against an outbreak that may happen later in the year, researchers have faced a tight schedule without all the information they would like to have had.
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