These three vaccines could save your life. Read on to see if they're a must for you.
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Chicken Pox (Varicella)

What's involved: A one-time series of two shots, at least four weeks apart
Who needs it: Anyone born after 1980 who did not either have chicken pox or get the two-shot vaccine series as a kid. Folks born before 1980 are presumed immune to chicken pox, according to the Centers for Disease Control and Prevention (CDC). However, if you're over 31 and have never had the disease, ignore the 1980 rule and get a blood test to check for virus antibodies, especially if you planning to get pregnant or you work in the healthcare field. If the blood test reveals you're not immune, start the vaccine series immediately. If you're already pregnant, start the series right after you give birth.
Why its worth it: Its a must if you're thinking about getting pregnant, since the virus can cause birth defects and stillbirth—and you can get it just from being in a room with someone who's sick. No matter what, its a good idea to get immunized because chicken pox tends to be a lot more severe in grown-ups than in kids: Half of all virus-related deaths occur in adults, even though adults account for less than 5% of cases.


What's involved: A one-time shot
Who needs it: Adults 60 and older. (Between 50 and 60? The Food and Drug Administration recently approved the vaccine for use in your age group, though the CDC hasn't decided whether to recommend you get it yet.)
Why its worth it: The vaccine can halve your risk for shingles, a debilitating illness that's essentially the return of chicken pox virus that's been hiding in your nerve endings for the last few decades. As our immune system weakens with age, the virus reemerges along the nerve pathways, causing a painful, blistery rash. Even after the rash disappears, shingles pain can linger for months, even years.

Pneumococcal Disease

What's involved: One shot plus a booster at 65 if its been more than five years since the first shot.
Who needs it: All adults 65 and older, as well as anyone who has a compromised immune system (say, due to an illness such as cancer or HIV).
Why its worth it: People in these particular groups are at a significantly high risk for a bloodstream infection caused by Streptococcus pneumoniae bacteria, explains William Schaffner, MD, president of the National Foundation for Infectious Diseases. These bacteria hang out harmlessly enough in our throats. But when our lungs become susceptible to infection due smoking, asthma, or a weakened immune system, "these bugs get into the lungs and into the bloodstream," he says. "Even today, in the 21st century, this infection has a mortality rate of 15 to 25%."