Getting a flu shot can help prevent influenza. But now, a large study in Britain indicates that older adults who get an annual flu vaccination are________________________________.
The study involved more than 78,000 people, age 40 and older. Researcher Niroshan Siriwardena of Britain's University of Lincoln led the study.
"Our research suggests that ________________________________by about 19%." The reduction was even higher, 21%, for people who got their vaccination early in the flu season. The results were mathematically adjusted to reflect the fact that ________________________________ are more likely to get a flu shot.
答案：
(1)less likely to suffer a heart attack(2)flu shots are associated with a reduction in relative risk of heart attack in adults
(3)people who are at higher risk for heart attack in the first place
