Are adults causing whooping cough epidemic?

There has been an unusual increase in whooping cough cases among 13 and 14 year olds in Washington, suggesting decreasing protection from the vaccine may be contributing to the epidemic. (AP Photo/Rich Pedroncelli)

Editor’s note: One overlooked reason for the increase in whooping cough cases in the U.S. this year: Adults who haven’t gotten their booster shots. According to the Centers for Disease Control and Prevention, just 8 percent of American adults have received the Tdap booster shot since it became available in 2006. Immunity from vaccinations in childhood wanes — meaning adults can carry and pass along the infection, even if their own symptoms are mild. That’s dangerous for babies, who aren’t yet fully vaccinated. In fact, one study found that 73 percent of babies with pertussis caught it from adults.

In this blog post, emergency physician Hazel Guinto-Ocampo, M.D., reviews the current facts about pertussis — as well as advice for vaccinating kids and adults.

Although there has been a steady increase in the number of pertussis (whooping cough) cases in the U.S. since the 1970s, this year, new cases are developing at an alarming rate. The CDC has already received reports of more than 18,000 cases in 2012, more than twice as many as this time last year. This level has not been seen since 1959. In Washington state, because of the disturbing rise in the number of reported cases, a pertussis epidemic was declared in April. Other states reporting heavy pertussis activity include Oregon, Nevada, New York, Minnesota, and Kentucky. In Philadelphia, 33 cases were reported in June, compared to an average of 3 cases confirmed during the same time period in the past 5 years.

There has been an unusual increase in cases among 13 and 14 year olds in Washington, suggesting decreasing protection from the vaccine may be contributing to the epidemic.

What is pertussis?

Pertussis begins with mild cold symptoms and cough. Fever is absent or minimal. The cough becomes repetitive and comes in fits (paroxysms), with the characteristic whooping sound with inhalation, commonly followed by vomiting. The paroxysmal cough can be distressing, can interfere with sleep, and lead to breakage of small blood vessels on the eyes, face, neck, and upper chest. Symptoms gradually improve over weeks to months; the illness can last from 6-10 weeks. The sickest patients are infants less than 6 months of age, who can suffer from complications such as pneumonia, seizures, encephalopathy, and death. Ten infant deaths have been reported to the CDC so far this year.

Pertussis is highly contagious. Young babies less than 2-3 months of age, who aren’t old enough to get vaccinated, are at greatest risk of catching the disease. Older siblings, and adults who may just have a mild coughing illness, are the most common sources of infection. Pertussis is most contagious early in the course of the disease. The incubation period ranges from 5-21 days.

Neither getting ill with pertussis nor vaccination, leads to prolonged protection from getting infected.

How is pertussis diagnosed?

Pertussis is diagnosed by obtaining mucus from the nose, with suctioning or using a swab. The results are generally available in a few days.

What is the treatment for pertussis?

Antibiotics for pertussis can help make the symptoms better or shorten the illness only when given early. Treatment is recommended for all cases to limit spreading the disease to others.

How can we prevent spreading pertussis?

The recommended immunization schedule for all infants and children include regularly scheduled pertussis vaccinations (the P component of DTaP), including a booster between 4-6 years of age. Another booster (Tdap) is recommended at 11-12 years of age. Although the vaccine is not perfect, vaccinated children develop a milder, shorter, and less severe disease.

It is also strongly recommended that pregnant women and other adults and family members who are in contact with babies receive Tdap vaccine. Data from 2010 suggest that only 8.2 percent of adults had the vaccine.

All close contacts (household, daycare, and school) of pertussis cases need treatment with antibiotics to prevent acquiring the illness. Unimmunized or underimmunized contacts will also need to get vaccinated.

When should pertussis be suspected?

Pertussis should be suspected in

  • any young infant with a coughing illness, especially if followed by vomiting.
  • any paroxysmal coughing or prolonged coughing illness in older children, teen-agers, or adults.
  • anyone who has been in contact with an infected person and develops respiratory tract symptoms within 21 days after the most recent contact.

Hazel Guinto-Ocampo, M.D., is the chief of pediatric emergency services at Bryn Mawr Hospital, and has 18 years of experience in the field of pediatric emergency medicine.

Have you had your pertussis booster shot yet?