Last reviewed by the Faculty of the Harvard Medical School on December 3, 2009
By Henry H. Bernstein, D.O.
Harvard Medical School
Parents in various communities across the United States may be getting letters from their children's schools saying that there has been a case of pertussis among the students or staff.
Pertussis, also called whooping cough, is always around. But over the past 10 years, there has been a notable increase in the number of cases reported in the United States especially among teens and adults. The U.S. Centers for Disease Control recorded more than 25,000 cases of pertussis, the highest number of cases reported in over 30 years.
Pertussis starts as an infection inside the nose but then can move to the lungs, causing serious breathing problems in some people, particularly young infants. Caused by the bacteria Bordetella pertussis, mild cases of whooping cough begin just like a cold or the flu, with runny nose, sneezing, and mild cough, usually without fever. Then, unlike the common cold, which usually gets better within a week or two, the cough of someone with pertussis actually gets worse. There are severe coughing spells, during which the child (or adult) coughs on and on, and may seem to choke or turn red or blue in the face. At the end of one of these coughing spells, the child may either vomit or "whoop" as they try to breathe in. The cough can last for weeks or even months, the so-called "hundred-day cough."
Pertussis infection can be very annoying because of the prolonged and persistent coughing, but it also has the potential to make some children and adults extremely sick. Complications from pertussis are most common in infants and very young children. These complications include stopping breathing (apnea), lung infections (pneumonia), seizures, brain swelling (encephalopathy), and even death. Almost two-thirds of infants younger than 6 months with pertussis end up in the hospital. In the past decade, between 13 and 21 children have died each year. Most of them were infants or children who had not received the right number of doses of the vaccine that helps to protect against this disease.
Pertussis is spread through contact (such as touching, kissing or shaking hands) with infected people and their secretions (for example, from a runny nose or cough). Symptoms usually appear a week or two after exposure to the bacteria. Unfortunately, pertussis is most contagious during the first two to three weeks of the infection, before the characteristic coughing spells begin. Therefore, it is often spread to others before someone begins to suspect the illness.
After many years of not hearing much about whooping cough due to pertussis, the number of diagnosed teenagers and adults has risen quite dramatically. You may know a person who has a long-lasting, irritating or hacking cough and does not know why. Whooping cough may be the reason. To avoid spreading the infection, especially to infants, the person should ask a health professional if pertussis may be causing the cough.
Pertussis is treated with an antibiotic. Most people would get better eventually without treatment, so the main reason for taking it is to help to stop the spread of the infection rather than actually treat it. Anyone being treated for pertussis, or "possible" pertussis, should take all prescribed medicine as directed and must stay away from infants and small children until they have taken at least five days of the antibiotic.
The best way to prevent this infection is the pertussis vaccine (part of the DTaP vaccine). Before the discovery of this vaccine, there were almost 150,000 cases of pertussis reported each year. Pertussis is the "aP" in the DTaP vaccine given to younger children. Children used to receive a different version of the vaccine, DTP, which was associated with more side effects. This acellular Pertussis vaccine contains only the parts of the bacterium that the body needs to trigger a protective response, instead of the whole bacterium. Licensed for children between the ages of 6 weeks and 7 years, this safe and effective vaccine is recommended for all children. Five doses are given, three in the primary series at 2 months, 4 months and 6 months of age; and then two booster doses at 15 months to 18 months of age and 4 years to 6 years of age.
We used to think that the immunity from childhood pertussis vaccines was life-long, but now we know that it wears off. Adolescents and adults can get the disease and spread it to younger children and infants. Thats why in 2005 a new vaccine, called Tdap, was released. The American Academy of Pediatrics recommends that adolescents ages 11 to 18 get the Tdap vaccine as a bootser instead of the older Td booster. The best time to do this is around age 11 or 12, when immunity to pertussis probably wears off. If they have already gotten the Td booster, they should still get a dose of Tdap so that they can be protected against pertussis. Waiting at least five years between getting the Td booster and getting the Tdap booster is recommended to reduce the risk of reactions to the vaccine. However, if there is a high risk for a person getting the disease and passing it onto an infant, the booster can safely be given as little as two years after the Td vaccine.
In light of the continued increase in the number of cases of pertussis, the most important things to remember are:
- Be sure that all children, including teenagers, are fully immunized against this potentially dangerous illness.
- Think about whooping cough when someone has an unexplained bad cough that lasts for more than one to two weeks.
- Teach our children (and remind ourselves) to:
- Cover our mouths and noses with a tissue or upper arm (not our hands) when we cough or sneeze.
- Throw away used tissues.
- Wash our hands frequently with soap and water or alcohol-based hand cleaners, especially after coughing or sneezing.
Henry H. Bernstein, D.O. is a senior lecturer in Pediatrics at Harvard Medical School. In addition, he is chief of General Academic Pediatrics at Children's Hospital at Dartmouth and professor of pediatrics at Dartmouth Medical School. He is the former associate chief of General Pediatrics and director of Primary Care at Children's Hospital Boston.