This year, as everyone knows by now, has been a pretty bad flu season. Predominated by a powerful strain of influenza A, an H3N2, disease activity has been widespread across the country. The major vaccine still in use, with technology essentially unchanged since the 1950s, is the vaccine manufactured using cultures of billions of hens’ eggs.
This has got to change. A newer vaccine, where the flu virus is cultured in mammalian cells, has been produced by Novartis (Flucelvax). Approved for use in the U.S. this past November, it has yet to become a big player on the flu vaccine scene. The advantages of the cell culture vaccine include less need for preservatives or antibiotics to prevent contamination, and usefulness in patients with severe egg allergies.
But the current vaccine has other limitations in addition to how it is made. It targets the proteins on the surface of the viral envelope, Hemagglutinin and Neuraminidase, and since the subtypes are always changing, the vaccine must be altered every year to cover them. The current vaccine is a trivalent vaccine, meaning it covers three strains, but predominant strains are often missed. Even if the vaccine becomes a quadrivalent vaccine, as is planned, it will still be imperfect. The success of the vaccine at preventing or ameliorating symptoms of the flu is 60 to 70 percent at best, hardly ideal.
In the future, a flu vaccine will be developed that targets a single protein common to all flu molecules. This protein may well be the M2 protein, at the center of the virus. This vaccine will work for several years, and will likely be far more effective than the current vaccine. Researching and developing this vaccine will cost over $1 billion, which is one of the reasons we don’t have it yet.
In the meantime, it is wise to get your flu shot. It is efficacious not only for those most at risk, but for everyone around them, to create a herd immunity by decreasing the amount of circulating flu virus.