March 13, 2013
Quadrivalent Flu Vaccines Will Be Available for
2013-14 Season

Washington, D.C.—As pharmacies prepare to order vaccine for the 2013-14 influenza season, they should be aware of some significant changes.

Among the most important may be the availability of quadrivalent vaccines, currently FDA-approved from two manufacturers and likely to become more widely available later this year.

The World Health Organization (WHO) included recommendations for both trivalent and quadrivalent vaccines for use during the 2013-14 influenza season, which occurs in winter in the northern hemisphere.

WHO said the trivalent vaccine should contain the following:
• An A/California/7/2009 (H1N1)pdm09-like virus
• An A(H3N2) virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011
• A B/Massachusetts/2/2012-like virus.

Quadrivalent vaccines that include two influenza B viruses should contain the above three viruses and a B/Brisbane/60/2008-like virus, according to WHO.

FDA’s vaccine advisory panel endorsed the WHO recommendation and said that the “B” strain used in this year’s vaccine be changed to offer a better match against B strains causing some influenza illnesses.

Quadrivalent vaccines already approved by FDA include GlaxoSmithKline’s Fluarix Quadrivalent for adults and children 3 years of age and older and MedImmune’s FluMist Quadrivalent (Influenza Vaccine Live, Intranasal) for ages 2 to 49.

In a press release, GlaxoSmithKline noted that “since the year 2000, two B virus strains (Victoria and Yamagata) have co-circulated to varying degrees each season. Various degrees of mismatch have occurred between the B strain included in trivalent vaccines and the B strain that actually circulated, causing an increased risk of influenza-related morbidity across all age groups—children, adults and the elderly.”

Leonard Friedland, MD, who heads GSK North America Vaccines Clinical Development and Medical Affairs, noted, “Trivalent influenza vaccines have helped protect millions of people against flu, but in six of the last 11 flu seasons, the predominant circulating influenza B strain was not the strain that public health authorities selected. Fluarix Quadrivalent will help protect individuals against both B strains and from a public-health standpoint, can help decrease the burden of disease.”

GSK will fulfill orders for both Fluarix Quadrivalent and its trivalent vaccines for the 2013-14 flu season.

In a press release, MedImmune noted, “FluMist Quadrivalent is similar to MedImmune’s trivalent Influenza Vaccine Live, Intranasal (FluMist), except FluMist Quadrivalent provides protection against an additional influenza strain,” and said on the product’s Web site that it will be available for the 2013-14 flu season.

Also recommended for the next flu season are the cell culture–based trivalent inactivated influenza vaccine (Flucelvax, Novartis), and the recombinant hemagglutinin influenza vaccine (FluBlok, Protein Sciences).

It is not clear, however, how much the flu vaccines with more strains will increase protection in some recipients, especially the elderly.

Updated and age-adjusted statistics for the 2012–13 influenza vaccine suggest only moderate effectiveness in preventing outpatient medical visits caused by circulating influenza viruses.

Overall, according to the national Centers for Disease Control, influenza vaccination reduced the risk for medical visits resulting from influenza A and B by 56%, from influenza A (H3N2) by 47%, and from influenza B by 67%.

While the preventive benefits against influenza B were consistent across age groups, the vaccine effectiveness estimates against influenza A (H3N2) viruses only were consistent (46%–58%) for those 6 months to 64 years.

“The non-significant adjusted VE of 9% against A (H3N2) among persons aged ≥65 years is similar to the estimate in a recent interim report from Europe and reinforces the need for continued advances in influenza vaccines, especially to increase protective benefits for older adults,” according to the CDC.

Public health officials said that, despite the low rate of protection in those older than 65, vaccination is the “the best preventive tool available” and should continue to be encouraged in that age group, which suffers the greatest morbidity and mortality from influenza.

U.S. Pharmacist Social Connect