US AIR FORCE, MATTHEW LOTZThe number of mumps cases has been increasing across the United States, a phenomenon that some researchers have suggested is due to evolution of the mumps virus to escape vaccination. But a more likely explanation is that vaccine-based protection against mumps wanes over a person’s lifetime, according to researchers at Harvard University. The findings, published yesterday (March 21) in Science, indicate a potential role for booster vaccines in maintaining protection throughout adulthood.
“Our results strongly support that the answer is waning vaccine-induced immunity, not a new vaccine-escape strain,” study coauthor Yonatan Grad, an infectious disease specialist at the Harvard T.H. Chan School of Public Health, tells The Philadelphia Inquirer.
Before the introduction of the mumps vaccine in 1967 in the U.S., more than 90 percent of children and adolescents came down with the infection. Although that percentage plummeted in the 1970s, the number of mumps infections saw spikes in the 1980s and 1990s, and again in 2006, particularly among young adults.
To understand the fluctuations, the Harvard researchers studied epidemiological data from a handful of studies carried out in Europe and in the U.S. between 1967 and 2008. The pair found that immunity from vaccination seems to ...
