The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices unanimously voted in favor of adding various recently licensed influenza vaccines to the list of acceptable vaccines for the prevention of influenza at the most recent meeting of the committee on Feb. 21.
The four influenza vaccines licensed by the Food and Drug Administration over the past year are two quadrivalent vaccines that include two influenza B strains and two influenza A strains; a cell-culture-based vaccine; and an egg-free, recombinant hemagglutinin vaccine manufactured without the use of influenza viruses.
These vaccines are expected to be available during the 2013-2014 influenza season, along with previously available vaccines, Dr. Lisa Grohskopf of the influenza division in the CDC’s National Center for Immunization and Respiratory Diseases said at the meeting.
She also provided an overview of new influenza vaccine abbreviations, reflecting the availability of the new vaccines. With the introduction of the quadrivalent vaccines, "we’ve had to replace our time-honored TIV abbreviation," replacing the abbreviation for trivalent inactivated vaccine (TIV) with IIV (inactivated influenza vaccine), she said.
The IIV class includes trivalent (IIV3) vaccines (those that are egg based and those that are cell-culture based) and quadrivalent (IIV4) inactivated vaccines. Cell-culture-based IIV is referred to as ccIIV or ccIIV3m. RIV3 refers to the trivalent recombinant hemagglutinin influenza vaccine, and LAIV and LAIV4 refer to live attenuated influenza vaccine.
The new vaccines "are acceptable alternatives to the other licensed vaccine products within specified indications," she said. But there are no formal recommendations proposed for using one vaccine over another when a provider has more than one vaccine that is available and appropriate for a given recipient, she added. Moreover, during her presentation Dr. Grohskopf emphasized repeatedly that providers should not delay vaccinating a patient in order to wait for a specific product.
The four new influenza vaccines are:
Flumist Quadrivalent (MedImmune). This quadrivalent live-attenuated influenza vaccine (LAIV4) was licensed in February 2012 for the same indication as the trivalent LAIV for healthy, nonpregnant people aged 2-49 years. Based on evidence from studies comparing the trivalent LAIV with IIV3 that indicate LAIV is more effective in children, providers "may consider use of LAIV4 rather than IIV for children in situations in which both vaccines are available and are otherwise appropriate," Dr. Grohskopf said. But vaccination should not be delayed if the LAIV4 is not available, she added.
• Fluarix Quadrivalent (GSK). This quadrivalent inactivated influenza vaccine (IIV4) was licensed in December 2012 for people aged 3 years and older. This vaccine is "an acceptable alternative" to other licensed products, used within indications. Both the trivalent version (IIV3) and IIV4 will be available in 2103-2014, but IIV3 will make up most of the supply. Either is acceptable, and since IIV4 "may provide broader coverage of circulating influenza viruses, providers who have access to both IIV4 and IIV3 may wish to consider IIV4 for individuals with conditions that confer high risk for influenza complications, when either vaccine is otherwise appropriate," Dr. Grohskopf said.
• Flucelvax (Novartis). This cell-culture-based inactivated influenza vaccine (ccIIV3) was licensed in November 2012 for people aged 18 years and older. It is also an acceptable alternative to other licensed products "used within indications," Dr. Grohskopf said. Although the vaccine viruses are not propagated in eggs, this vaccine cannot be considered completely egg free, but it is expected to contain "considerably less egg protein than other IIVs." Providers "may consider use" of ccIIV3 for egg-allergic patients aged 18 years and older, but "vaccination of mildly egg-allergic individuals should not be delayed if ccIIV3 is not available," when any licensed IIV should be administered, she noted.
• Flublok (Protein Sciences). This recombinant hemagglutinin vaccine (RIV3) – the first purified, recombinant hemagglutinin (HA) protein influenza vaccine, manufactured without the use of influenza virus – was licensed for adults aged 18-49 years in January 2013. The vaccine contains 45 mcg of each HA component, more than other vaccines, and contains no egg protein, preservative, or latex, Dr. Lisa M. Dunkle, chief medical officer at Protein Sciences, said at the meeting. She said that 3-5 million doses of Flublok, which is contained in single-use vials, are expected to be available for the 2013-2014 season. The company is working on a quadrivalent version of Flublok.
RIV3 is truly egg free, and in a situation where both IIV and RIV3 are available and "otherwise appropriate," a provider could consider using RIV3 for people aged 18-49 years who have a mild egg allergy, Dr. Grohskopf said. But vaccination should not be delayed if RIV3 is not available. RIV3 is not contraindicated in people with anaphylaxis to egg.