Dianne Feinstein's Health Remains a Mystery as Calls for Her to Step Down Increase.

California Senator Dianne Feinstein's absence from the Senate is due to her battle with shingles, a painful and potentially debilitating disease caused by the reactivation of the varicella zoster virus. Shingles is more likely to last longer and cause chronic nerve pain in older patients. It can also raise the risk of stroke and heart attacks. Prevention is key, and a two-dose vaccine capable of preventing shingles in adults ages 50 and over for at least a decade is available.