Pertussis Outbreaks

Pertussis (whooping cough) is a common (endemic) disease in the United States. There are peaks in reported cases of pertussis every few years and frequent outbreaks. In 2012, the largest peak in recent years, states reported 48,277 cases of pertussis. During pertussis outbreaks, the primary goal is to protect babies from getting sick and dying from pertussis. A second goal is to protect people of all other ages from getting pertussis.

Identifying Pertussis Outbreaks

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Pertussis outbreaks can be difficult to identify and manage, and cases of pertussis may go unreported. Other respiratory pathogens often cause symptoms similar to pertussis. Also, pertussis co-circulates with other pathogens (bacterial and viral) at times.

Healthcare professionals commonly use polymerase chain reaction (PCR) tests to diagnose pertussis. PCR tests vary in their ability to correctly show who does not have pertussis (specificity). This is important because if a test has a high specificity and someone tests positive, then it is very likely they actually have the disease.

Since PCR tests vary in specificity, CDC recommends getting confirmation with culture (a lab test where the bacteria are grown) for at least one suspected case any time there is suspicion of a pertussis outbreak.

False (pseudo) outbreaks of pertussis have resulted because of false positive test results with PCR. This highlights the importance of recognizing clinical signs and symptoms and practicing careful laboratory testing.

Protecting Babies

To reduce the risk of pertussis in new mothers and their young babies, CDC recommends that pregnant women receive Tdap vaccine during each pregnancy.  The recommended time to get the shot is the 27th through 36th week of pregnancy, preferably during the earlier part of this time period.

During outbreaks, prevention efforts should focus on improving rates of Tdap vaccination among pregnant women to reduce serious illness and possible deaths in vulnerable babies.

Using Antibiotics

More cases of pertussis are occurring and spreading through communities. Therefore, it may not be effective for health departments to

  • Spend a lot of time and resources looking for those exposed to pertussis (extensive contact tracing)
  • Provide antibiotics to all contacts to help prevent further cases of pertussis (post exposure antimicrobial prophylaxis, or PEP)

Antibiotics may prevent pertussis if given before symptoms begin. However, there are no data showing that widespread use of PEP among contacts of people with pertussis works well to control or limit the size of pertussis outbreaks.

Given these considerations, CDC supports targeting PEP to people

  • At high risk of developing a serious case of pertussis, such as young babies
  • Who will have close contact with those at high risk of developing a serious case of pertussis

Another important consideration is the overuse of antibiotics. CDC is engaged in actively promoting the appropriate use of antibiotics among healthcare professionals and patients. See PEP guidance.

Active Screening

Public health officials may consider active screening for symptomatic patients with suspected pertussis during outbreaks in settings such as schools, day care centers, and hospitals. Active screening for suspected cases may:

  • Reduce exposure to people with pertussis
  • Encourage timely medical evaluation and treatment of cases
  • Promote prompt administration of antibiotics to high-risk close contacts
Page last reviewed: November 18, 2019