This news release is available in Japanese.
Vaccination against measles doesn't just protect people from the measles virus -- it also prevents other infectious diseases from taking advantage of peoples' immune systems after they have been damaged by measles, according to a new study. These findings help to explain why the introduction of measles vaccines prevented so many more deaths than researchers had expected, while highlighting the importance of widespread vaccination campaigns. Michael Mina and colleagues analyzed data from before and after mass measles vaccinations began in England, Wales, the United States, and Denmark. Their results suggest that measles damages the memory of one's immune system so that it forgets how to fight off a wide range of bacterial invaders. Although previous studies have suggested that measles induces a kind of "immune amnesia" for weeks or months after infection, this new study reveals that this measles-induced immune damage can last for two to three years. During that time, individuals who have fought off the measles virus are vulnerable to a slew of opportunistic pathogens, according to the researchers. This population-level analysis shows a correlation between measles incidence and deaths that occur from other infectious diseases in the two to three years following a measles infection. It also suggests that measles vaccinations played a primary role in driving down mortality from other infectious diseases in all of the high-income countries studied. Taken together, the researchers' findings imply that measles vaccines keep immune systems' memories intact, thereby providing a degree of herd protection against non-measles infections.
Article #16: "Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality," by M.J. Mina; C.J.E. Metcalf; B.T. Grenfell at Princeton University in Princeton, NJ; M.J. Mina at Emory University School of Medicine in Atlanta, GA; C.J.E. Metcalf; B.T. Grenfell at Fogarty International Center, National Institutes of Health in Bethesda, MD; R.L. de Swart; A.D.M.E. Osterhaus at Erasmus University Medical Center in Rotterdam, Netherlands.