Illustration: Anna Parini

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You may think you’ve had all the immunizations you’ll ever require, but the guidelines are constantly being fine-tuned— for the good of us all. Every year, the Centers for Disease Control and Prevention updates its immunization schedule; the past few years have brought notable changes, and there may be more to come. Keep reading to see if you'll need to roll up a sleeve anytime soon.

Tdap

Guards against tetanus, diphtheria, and pertussis (a.k.a. whooping cough).

What’s new: As of last October, a Tdap shot is recommended for pregnant women as early as possible during their last trimester. Experts also advise everyone age 11 and older to get the shot if they haven’t already, especially if they’re around newborns.

Why: Scientists are now realizing that the Tdap vaccine wears off faster than once hoped (as does its childhood equivalent, DTaP). Four years after getting Tdap, only 30 to 40 percent of people are fully protected from pertussis, which is likely one reason cases have spiked in recent years. The vaccine is still the best defense we have against this highly contagious respiratory disease, which can cause coughing fits violent enough to crack a rib. Pertussis is especially dangerous for babies too young to receive the shot: About half of infected infants under a year old need to be hospitalized.