Mumps is resurging. And it may be because the immune response provoked by the mumps vaccine weakens significantly over time, and not because people are avoiding vaccination or because the virus has evolved to develop immunity to the vaccine, a study found.

The mumps resurgence has been largely in people 18 to 29, most of whom received the recommended two shots in early childhood, and not in older people who gained immunity through natural infection before the vaccine was developed.

Using data from epidemiological studies and mathematical models, researchers found that the resurgence, which began in 2006, has left about a third of children 10 to 14 at risk. The researchers estimate that about 25 percent of vaccinated people will lose their immunity in 8 years, 50 percent in 19 years, and 75 percent in 38 years. The study is in Science Translational Medicine.

“We’ve seen the outbreaks of mumps in vaccinated populations,” said the lead author, Joseph A. Lewnard, a research associate at the Harvard T.H. Chan School of Public Health, “in contrast to measles, where it’s only been in unvaccinated pockets.”

A third shot for mumps is recommended during outbreaks, Lewnard said.

Some omega-6 acids may help heart

Are omega-6 fatty acids, the fats found in nuts, seeds and many vegetable oils, including those used in many processed and junk foods, helpful or harmful?

It has been believed that omega-6s generally increase inflammation, while omega-3s, the fats in fish oil, lower it, and some studies suggest that a high omega-6 intake increases the risk for heart disease. But a new long-term study suggests omega-6s can be good for the heart.

Finnish researchers studied 2,480 men aged 42 to 60, following them for an average of 22 years.

The study, in the American Journal of Clinical Nutrition, found that compared with men in the lowest one-fifth for blood levels of omega-6, those in the highest fifth had a 43 percent lower risk of death from any cause and a 46 percent lower risk of cardiovascular death. The study controlled for factors such as smoking, hypertension and family history of heart disease.

“This is not a license to eat junk or processed food,” said the lead author, Jyrki K. Virtanen, an adjunct professor of nutritional epidemiology at the University of Eastern Finland. “But there is no need to fear omega-6 in vegetables, nuts and seeds. It clearly has benefits for heart disease prevention.”

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