All other currently available licensed seasonal influenza vaccines are trivalent, containing 3 strains -- 2 strains of type-A influenza (A/H1N1 and A/H3N2) and 1 B-lineage strain. FluMist Quadrivalent (influenza vaccine live) contains 4 strains (2 type-A strains and 2 type-B lineages) to help provide broad protection against circulating influenzas A and B.
In recent years, influenza B strains from 2 different lineages (B/Yamagata and B/Victoria) have circulated. The quadrivalent vaccine includes strains from both lineages, helping provide protection against both B lineages.
“A vaccine containing the four virus strains most likely to spread and cause illness during the influenza season offers an additional option to aid in influenza prevention efforts,” Karen Midthun, MD, director of FDA’s Center for Biologics Evaluation and Research, said in FDA’s announcement of the approval.
A quadrivalent vaccine might have prevented millions of flu cases, Stan Block, MD, FAAP, professor of clinical pediatrics at the University of Kentucky College of Medicine, Lexington, and at the University of Louisville School of Medicine, said in a press release from MedImmune.
“According to the Centers for Disease Control and Prevention (CDC) … in 5 of the 10 influenza seasons between 2001 and 2011, the predominant circulating influenza B lineage was different from the 1 selected for inclusion in the trivalent vaccines,” Dr Block said. “The CDC has estimated that between 2001 and 2009, 2.7 million fewer Americans would have gotten the flu if all influenza vaccines had been quadrivalent."
In pivotal clinical studies conducted in children and adults aged 2 to 49 years, FluMist Quadrivalent was compared to 2 trivalent formulations of MedImmune's licensed seasonal influenza vaccine, FluMist (influenza vaccine Live, intranasal), the company stated.
FluMist Quadrivalent had a safety profile generally comparable to the trivalent FluMist formulations, and immunogenicity to individual vaccine strains was comparable in trivalent and quadrivalent formulations. Further, the addition of the second B strain did not result in immune interference to other strains included in the vaccine.
You should not get FluMist Quadrivalent if you have a severe allergy to eggs, gentamicin, gelatin, or arginine; have ever had a life-threatening reaction to influenza vaccinations; or are aged 2 through 17 years old and take aspirin or medicines containing aspirin, the company said. Children or adolescents should not be given aspirin for 4 weeks after getting FluMist or FluMist Quadrivalent unless a healthcare provider says otherwise.
Children under aged 2 years old have an increased risk of wheezing (difficulty with breathing) after getting FluMist Quadrivalent.
According to the MedImmune news release, healthcare providers should be aware if the parent or child are currently wheezing; have a history of wheezing if under aged 5 years; have had Guillain-Barre syndrome; have a weakened immune system or live with someone who has a severely weakened immune system; have problems with heart, kidneys, or lungs; have diabetes; are pregnant or nursing; or are taking Tamiflu, Relenza, amantadine, or rimantadine.
The most common side effects are runny or stuffy nose, sore throat, and fever over 100 F.
Source : Drug Topics
