When Will We Get the Flu Vaccine Right?

It is a truism of microbiology that very small creatures have an evolutionary advantage over us. Their tiny size, rapid procreation and sky-high populations make germs ideally equipped to develop fortuitous mutations which render them immune to our defenses. This is as true in vaccines as it is in the body, which helps to account for our poor success with seasonal flu shots.

A comprehensive review of the flu vaccine of 2012 found some grim numbers:

[V]accine effectiveness against H3N2, the main flu strain circulating that season, proved to be only 46% in adults aged 18–49, 50% in those aged 50–64, and a dismal 9% in people aged over 65, a vulnerable group. Flu hospitalizations and deaths were the highest in almost a decade. What went wrong?

The answer is complex, and may involve everything from flawed human guesswork, to the inherent power of influenza, to fundamental weaknesses in the way vaccines are manufactured. Strains of flu which are considered the best estimates for a given season’s outbreak are often combined with other strains to help them incubate more rapidly. Now researchers believe this combination may dilute their potency as vaccines:

Skowronski says that the findings should prompt discussion of switching vaccine production from eggs, a 1930s technology, to modern production systems using cultured human cells.

We’re getting better at this, and there is no question that the numbers still strongly recommend getting a flu shot. But until we perfect a production method that accounts for the most likely flu mutations within a given year, it is still wise to follow the advice of your grandmother: get sleep, wash your hands and avoid anyone who looks like they haven’t kept a meal down in a week.

Tags: flu vaccines, sinus symptoms, studies