|Posted on November 5, 2017 at 9:40 AM|
Predicting the correct strain or strains of influenza against which to vaccinate presents an enormous challenge for public health authorities and vaccine manufacturers. Flu vaccines aim to be effective against influenza A and B, but these strains comprise only about 10 percent of all circulating viral strains that cause ILI. Furthermore, the flu virus mutates from year to year, so predicting the exact serotype can be elusive. The actual risk that any ILI is actually the flu is low.
The Cochrane Collaboration's meta-analysis on the flu vaccine concluded that the influenza vaccine's efficacy is 30 percent in most years and 59 to 70 percent in a good year. Vaccine manufacturers make effectiveness claims based on antibody response alone; they do not address whether the vaccine in question actually prevents the disease or not. The FDA measures only antibody production, which may or may not be associated with protection against disease. Thus, a significant number of those vaccinated never mount an antibody response or have immunity against a disease. Immunity and immune response might involve a few immune pathways and might involve other cofactors. In addition, the duration of vaccine-induced protection is uncertain as well.
Toni Bark, MD, MHEM, LEED AP
Categories: Vax Facts