Pertussis, also known as whooping cough, is a respiratory illness caused by the bacterium Bordetella pertussis. Pertussis spreads through the air and is highly contagious—and in some cases, even deadly. A vaccine for pertussis was developed and entered widespread use in the United States in the 1940s. After the introduction of the vaccine, the number of deaths in the U.S. due to pertussis declined dramatically—from 9,000 deaths a year to about 20 deaths a year. Unfortunately, most of the deaths today occur in babies younger than six months old, because they have not completed their vaccine series and are susceptible to infection. Most adults have been vaccinated against pertussis. Unfortunately, the vaccine doesn’t provide lifetime immunity; its efficacy will fade over time. Adults who contract pertussis are likely to have a milder case, but are at risk of spreading the infection to infants who aren’t protected. That’s why it’s important for everyone, especially grandparents and other adults who come into contact with infants, to receive a booster vaccine for pertussis, called a Tdap shot. Tdap boosts immunity to pertussis (as well as diphtheria and tetanus) and reduces the chances that a person will become infected. Understanding Whooping Cough Whooping cough starts off like a regular upper respiratory tract infection with symptoms like a runny nose, a low grade fever, and a mild cough. During this phase, it's very contagious. Then, after one to two weeks, a serious cough develops, with rapid coughing fits that can sometimes be followed by a deep breath in; this is where the disease gets its name, because the deep breath can sound like a “whoop.” That phase can last for up to six weeks and it’s a truly miserable experience. And unfortunately, that's not the end of it. It will improve over time, but people can continue to have a cough for months. For young infants, infection can result in lower lung disease. Infants with pertussis can have episodes in which they stop breathing and can progress to respiratory failure. In severe cases, death can occur. Understanding the Whooping Cough Vaccine and Booster The full primary vaccination series against pertussis takes several years to complete. Infants in the U.S. typically receive doses at 2, 4, 6, and 15 to 18 months old, and again between the ages of 4 and 6 years old. A booster dose of Tdap is then given at 11 or 12 years of age. Protection against pertussis should begin before birth. Pregnant women should receive the Tdap booster shot in their third trimester of each pregnancy. In this way, protective antibodies from the mother can pass to the infant before birth. Despite these protective antibodies, infants remain susceptible to pertussis. Because of this, it is especially important for adults who have contact with new babies, like grandparents, aunts, uncles, childcare workers and healthcare professionals, to be vaccinated against pertussis with the Tdap vaccine. Adults should have a booster dose of a tetanus-containing vaccine every 10 years. If an adult has not had Tdap, this should be used as the booster dose. Vaccines can take several weeks to stimulate an antibody response, so it is important to be vaccinated well in advance of having contact with infants (at least two weeks is recommended). Pertussis vaccines are very safe and can be given in your doctor’s office. Because these vaccines are recommended as a part of the U.S. vaccination schedule, they are generally covered by insurance. There is no need to hold any medications or fast before reciving a pertussis vaccine. The main side effect of pertussis-containing vaccines is soreness at the site of the injection. This is generally mild and resolves quickly. The benefit of vaccination includes protection for yourself against a serious respiratory infection and protection for the most vulnerable around you from a serious and even life-threatening illness.