QUESTIONS ABOUT flu vaccine for older people: “A growing number of immunologists and epidemiologists say the vaccine probably does not work very well for people over 70, the group that accounts for three-fourths of all flu deaths.” But studies are complicated by the fact that healthier older people are more likely to get vaccinated. Assuming this is true, I wonder if the vaccine could be reformulated to be more effective in older recipients, or if older immune systems just don’t respond as well.