American Association for Clinical Chemistry
Better health through laboratory medicine
March 2010 Clinical Laboratory News: Key Flu Indicators Level Off

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March 2010: Volume 36, Number 3


Key Flu Indicators Level Off
FDA's Emergency Use Authorizations for Detecting the 2009 H1N1 Virus

In April 2009, the U.S. Secretary of Health and Human Services declared a public health emergency due to the outbreak of the 2009 H1N1 influenza virus. Now according to the most recent data from the Centers for Disease Control and Prevention, the overall cumulative hospitalization rates for the 2009-2010 influenza season have leveled off in all age groups and very few 2009 H1N1-laboratory confirmed hospitalizations were reported by states during the week ending January 30.

Nevertheless, confirming the identity of the virus responsible for influenza-like illness remains important for administering appropriate therapy to individuals, as well as the general public health. “The need to correctly identify influenza subtypes was demonstrated during the height of the 2009 H1N1 pandemic,” said Andy Shrago, senior director of sales and marketing at Gen-Probe Prodesse. “With different pharmaceutical susceptibility profiles for each of the three strains, we expect that laboratory and physician needs will be best met by products that can reliably detect and differentiate all three strains of influenza A—seasonal H1, seasonal H3, and 2009 H1N1.”

To help speed identification of the virus, the Food and Drug Administration (FDA) issued 13 emergency use authorizations (EUAs), making assays available for diagnosing 2009 H1N1 influenza virus under certain circumstances (see Table). It is important to note, however, that FDA has not cleared or approved any tests for the identification of the 2009 H1N1 influenza virus. Under its authority, FDA can permit the use of unapproved and uncleared medical products in a public health emergency provided certain criteria are met. FDA can only grant EUAs for the duration of the emergency, which is currently set to expire on April 26, 2010, unless it is terminated sooner or renewed. The agency can also revoke any EUA prior to the termination of the emergency.

In contrast to 2009, this year manufacturers will need to develop assays that are able to accurately and effectively differentiate multiple strains, says Shrago. “While the IVD community did an outstanding job serving public health needs by quickly getting 2009 H1N1-only tests to market through the FDA’s EUA process, labs will demand post-pandemic, complete subtyping assays in the coming months to meet clinical requirements,” Shrago predicted.