Flublok Influenza Vaccine May Protect Seniors Better

Proteins made in the recombinant process are genetically more similar to the original vaccine strains than egg produced vaccines

Health officials have recognized for many years that people 50 years and older are at greater risk of influenza complications.

That’s because human immune defenses become weaker with age. During most flu seasons, seniors suffer the greatest.

In recent years, it’s estimated that between 71 to 85 percent of seasonal flu-related deaths have occurred in people 65 years and older.

A recent clinical trial compared the protective efficacy in older adults of a quadrivalent, recombinant influenza vaccine (RIV4) with a standard-dose, egg-grown, quadrivalent, inactivated influenza vaccine (IIV4).

This study focused on the A/H3N2-predominant 2014–2015 influenza season, when antigenic mismatch between circulating and vaccine influenza strains resulted in the reduced effectiveness of many licensed vaccines.

The research found the RIV4 provided better protection for seniors than standard-dose IIV4 against confirmed influenza-like illness.

It takes several months to grow vaccines using the standard egg-based methods, but the recombinant technology can be produced in 3 to 6 weeks.

Which means during flu seasons when the vaccine strains appear to be mismatched with the circulating virus, a new vaccine could be quickly produced.

“The Flublok quadrivalent vaccine met a prespecified non-inferiority benchmark in a randomized, double-blind clinical trial involving adults ages 50 and older,” according to Lisa Dunkle, MD, of Protein Sciences, and colleagues.

Dr. Dunkle said “the apparent superior efficacy of the recombinant vaccine is likely caused by two factors: it contains three times the amount of HA proteins compared with the standard drug, and the proteins themselves have greater "genetic fidelity" to the wild-type viruses.”

Flublok was the world’s first recombinant protein based influenza vaccine. During June 2013, the Advisory Committee on Immunization Practices (a Centers for Disease Control and Prevention advisory committee) unanimously recommended Flublok for adults including those with egg allergies.

The CDC Vaccine Price Lists posted on this website provides the private sector vaccine prices for general information.

This study received financial support by a contract (HSSO 100200900106C) with Protein Sciences, the producer of Flublok, from the Biomedical Advanced Research and Development Authority.

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org - Drs. Dunkle, Izikson, and Cox report being employed by and holding stock in Protein Sciences; Dr. Patriarca, receiving consulting fees from Altimmune, FluGen, Georgia Institute of Technology, Medicago, VaxInnate, Vaxart, Vivaldi Biosciences, Moderna Therapeutics, Novavax, Seqirus, and Visterra; and Dr. Goldenthal, receiving consulting fees from Pfizer, Johnson & Johnson, Novartis, and the Bill and Melinda Gates Foundation. No other potential conflict of interest relevant to this article was reported.