Quadrivalent Vaccines for Add Influenza B Protection Recommended
The strains of influenza virus to be included in next years seasonal flu vaccine have been determined. the 2013-2014 vaccine will provide options for both trivalent and quadrivalent vaccines and include flu strains from the 2012-2013 vaccine plus addition strains. The typical flu vaccine contains three flu strains (trivalent) two Influenza A and one Influenza B. For the first time, a vaccine containing protection against four strains of influenza, a quadrivalent vaccine, will be an option.
According to the Centers for Disease Control and Preventions weekly surveillance update:
Additional Commons Sense InfluenzaThe World Health Organization (WHO) has recommended vaccine viruses for the 2013-2014 Northern Hemisphere vaccines, and the Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) has made recommendations for the composition of the 2013-2014 influenza vaccines to be used in the United States. Both agencies recommend that trivalent vaccines contain an A/California/7/2009-like (2009 H1N1) virus, an A(H3N2) virus antigenically like the cell-propagated, or cell-grown, virus A/Victoria/361/2011 (A/Texas/50/2012), and a B/Massachusetts/2/2012-like (B/Yamagata lineage) virus. It is recommended that quadrivalent vaccines containing an additional influenza B virus contain a B/Brisbane/60/2008-like (B/Victoria lineage) virus in addition to the viruses recommended for the trivalent vaccines. These recommendations were based on global influenza virus surveillance data related to epidemiology and antigenic characteristics, serological responses to 2012-2013 seasonal vaccines, and the availability of candidate strains and reagents.
The inclusion of an additional influenza B virus ("It is recommended that quadrivalent vaccines containing an additional influenza B virus...in addition to the viruses recommended for the trivalent vaccines") appears to be a result of the 2012-2013 flu season. As the CDC notes they have characterized 1,340 influenza viruses since October, 2012. Of those influenza viruses, 105 have been H1N1 2009, 827 N3N2 influenza A and 408 influenza B. Also, according to the CDC:
"Since the start of the season, influenza A (H3N2) viruses have predominated nationally, however in recent weeks, the proportion of influenza B viruses has been increasing. During week 8, 53% of all influenza positive specimens reported were influenza B viruses."
The Food and Drug Administration Vaccines and Related Biological Products Advisory Committeemade the final recomendation at their meeting in February, 2013. According to the FDA website, the Vaccicnes and Related Biological Products Advisory Committee "reviews and evaluates data concerning the safety, effectiveness, and appropriate use of vaccines and related biological products..."
The FDA committee recommended next years influenza vaccine should retain the current influenza A H1N1 strain and replace the influenza A H3N2 component with an A H3N2 virus. They also recommend replacement of the current influenza B strain, the B/Victoria lineage strain.