The link between imperfect vaccines and disease

New mathematical models explore why some vaccines are more effective than others. A new mathematical model that tests the effectiveness of different vaccine types could help explain why certain diseases are still prevalent despite mass vaccination programs. The model, which is detailed in a study published in a recent issue of the SIAM Journal on Applied Mathematics, examined the effects that different vaccine types have on individuals compared to the population as a whole. Vaccines are designed to elicit an immune response that is similar to what would be triggered by a natural infection, but without causing the actual disease. “An ideal vaccine would provide perfect protection that lasts forever,” the study’s first author Felicia Magpantay, a postdoctoral fellow at the University of Michigan in Ann Arbor, said in an email. In real life, however, no vaccine is perfect. They all fail in some way. Magpantay and her colleagues looked at the individual and population-level...