The Tdap vaccine is a combination vaccine that protects against three serious diseases: tetanus, diphtheria, and pertussis (whooping cough). It is recommended for preteens, teens, and adults, especially those who are in close contact with infants. The vaccine helps prevent these infections, which can lead to severe health complications. The Tdap vaccine is typically given as a single shot, with booster doses recommended every ten years. Pregnant women are also advised to receive the vaccine during each pregnancy to help protect their newborns from pertussis. Overall, vaccination is a key measure in maintaining public health and preventing outbreaks.