Source: San Francisco Chronicle
By: Allday, Erin
The Centers for Disease Control and Prevention says this year’s flu vaccine appears to be well matched to the circulating influenza strains. Even so, researchers continue to work toward the “holy grail” of immunization: a lifelong flu vaccine. Right now, the flu vaccine must be reformulated and administered every year, and even though people retain some resistance to a particular strain when they are infected, constant changes in the virus hinder natural protection. Moreover, a person’s immune response to the vaccine declines in their mid-30s, with the elderly producing smaller numbers of antibodies than younger individuals, and the vaccine’s effectiveness wanes after a matter of months regardless of age. The flu vaccine contains parts of a protein found on the surface of the influenza virus, which is recognized and attacked by antibodies; but this protein, hemagglutinin, is different in each strain of influenza, posing a challenge for vaccine developers. “The goal is to find a region of the influenza germ that can’t change, and develop a vaccine against that conserved region. The problem is that pretty much all of those regions that we’ve found so far are buried in the virus,” says Dr. Randy Bergen, clinical lead for Kaiser Permanente’s Northern California Flu Vaccine Program. “Even if we were able to make an antibody for that region, the virus would have replicated before the antibody could get in there and attack.” As researchers look to create a longer-lasting flu vaccine, they are considering chemical adjuvants and DNA vaccines, the latter of which will soon undergo a clinical trial at Stanford University.