Children's Health

Whooping Cough and the DTaP Vaccine

Bordetella pertussis is a bacterium that can live in the human respiratory tract. Pertussis, or whooping cough, is spread through secretions from sneezes and coughs. Most pertussis infections are passed between family members and household contacts, such as babysitters. The infection can be prevented with DTaP vaccines given to young children. Babies are given a shot at 2 months, 4 months, and 6 months old. The fourth shot is given at 15-18 months, and the fifth shot at 4-6 years.

How contagious is whooping cough?

Whooping cough is highly contagious. If one person has the pertussis bacteria, each unvaccinated household contact has up to 90% chance of catching the infection as well.

How can someone catch whooping cough if they’ve already been vaccinated?

Unlike some vaccines, the pertussis vaccination may not provide lifelong immunity to the disease. Immunity may wane 5-10 years after the last childhood vaccine.

Can I carry the pertussis bacteria without knowing it?

Experts believe it’s rare or impossible to carry or transmit pertussis without any symptoms. However, if you’ve been immunized, your symptoms may be mild -- but still infectious. Cold symptoms might occur at the beginning of the infection, and a cough will sooner or later be present.

If the vaccine wears off so quickly, why don’t more adults catch pertussis?

Hundreds of thousands of people do catch pertussis each year, but they don’t usually realize it. The pertussis vaccine reduces the severity of whooping cough, so most vaccinated teens and adults experience relatively mild symptoms.

How effective is the childhood pertussis vaccine, DTaP?

After the third dose -- given at age 6 months -- children have 80% to 85% immunity against pertussis. Protection lasts from three to five years. The DTaP shot also protects against tetanus and diphtheria.

Can I prevent whooping cough by hand washing and avoiding sick people?

Hand hygiene and covering coughs and sneezes may prevent some pertussis transmission. However, vaccination (in childhood and again in adolescence or adulthood) is considered the only effective means of prevention.

Who should get revaccinated against pertussis?

Federal guidelines advise that everyone from age 11 up should receive the Tdap booster shot. Pregnant women are also advised to get vaccinated, preferably between 27 and 36 weeks' gestation. 

What is Tdap?

Tdap is a combined tetanus, diphtheria, and pertussis booster vaccination. The vaccine is given in a single shot to ages 10 or 11 (depending on the specific vaccine) and up.

How effective is the Tdap booster shot?

Tdap provides 90% renewed immunity against pertussis. Tdap is also effective at preventing tetanus and diphtheria. After a Tdap booster shot, adults need a Td booster shot every 10 years. Td provides continued protection against tetanus and diphtheria.

What are the risks of DTaP and Tdap?

The risks of DTaP, Tdap, and other common vaccines are very low. Soreness and inflammation at the injection site are most common. Some people may experience a short period of malaise or low-grade fevers. Allergic reactions to vaccines are extremely rare, but can be serious. The risks of tetanus, diphtheria, and pertussis are higher than the risks of reactions to the vaccines.