Influenza virus places a large burden on our society. It is estimated that the costs of everything related to influenza virus infection comes to about $87.1 billion US dollars in the United States. With the existing vaccination program against influenza virus, you may ask why there isn’t a “one size fits all” that can make us completely immune from influenza virus infection with a single vaccine. My parents have asked me that question a few weeks ago. The way how I explain it is through the use of umbrellas. Let’s say the virus carries a bright red umbrella. The immune system recognizes the red cloth on the umbrella and then mount an immune response against the red cloth. But next year, the virus mutates due to selective pressure. The virus now carries a blue umbrella. The immune system now has to go through all the processes from sensing the infection to getting rid of the infection, instead of recognizing the virus at the beginning of the infection. The current strategy that the scientists are trying to develop is the use of broadly neutralizing antibody. The broadly neutralizing antibody recognizes not the cloth of the umbrella, but the stalk of the umbrella which is common among all subtypes of influenza.
A recent review article by Dr. Krammer and Dr. Palese from Mount Sinai has covered the challenge of this antibody in an elegant way. The real challenge behind the application of a broadly neutralizing antibody against influenza virus is that different age groups tend to have totally different exposure history to the subtypes of influenza virus. Children tend to be naive for influenza virus infection when adult are exposed to it multiple times. Furthermore, the elderly appears to mount a less effective response after a flu shot. Thus, the application of the broadly neutralizing antibody needs to be tested extensively in different age groups before rolling out.
“The initial cost of conducting these trials might seem high, but investment in universal influenza virus vaccine approaches might make it possible to overcome the threat of seasonal and pandemic influenza.”