Outbreaks

Español: Brotes

Pertussis is an endemic (common) disease in the United States, with periodic epidemics every 3 to 5 years and frequent outbreaks. In 2010, 27,550 cases of pertussis were reported — and many more cases go unreported. The primary goal of pertussis outbreak control efforts is to decrease morbidity (amount of disease) and mortality (death) among infants; a secondary goal is to decrease morbidity among persons of all ages.

Pertussis outbreaks can be difficult to identify and manage. Other respiratory pathogens often cause clinical symptoms similar to pertussis, and co-circulation with other pathogens (bacterial and viral) does occur. In order to respond appropriately (e.g., provide appropriate antibiotic prophylaxis), it is important to confirm that B. pertussis is circulating in the outbreak setting and to determine whether other pathogens are contributing to the outbreak. Polymerase chain reaction (PCR) tests vary in specificity, so obtaining culture confirmation of pertussis for at least one suspicious case is recommended any time there is suspicion of a pertussis outbreak.

Pseudo outbreaks of pertussis have resulted because of false positive test results with PCR. This underscores the importance of recognizing clinical signs and symptoms and practicing careful laboratory testing.

Institutional outbreaks of pertussis are common. Outbreaks at middle and high schools can occur as protection from childhood vaccines fades. In school outbreaks, prophylaxis is recommended for close classroom and team contacts — and the pertussis booster vaccine (Tdap) depending on age. Pertussis outbreaks in hospitals and other clinical settings can put infants and other patients at risk.

Questions and Answers

Outbreak-Related Questions and Answers

Recent Outbreak Activity

Localized outbreaks of pertussis are not uncommon and occur throughout the year. Some examples of pertussis activity in the US include:

• In 2010, 9,143 cases of pertussis (including ten infant deaths) were reported throughout California. This is the most cases reported in 63 years when 9,394 cases were reported in 1947 and the highest incidence in 52 years when a rate of 26.0 cases/100,000 was reported in 1958. Previously, the peak was in 2005 when there were 3,182 cases reported. In 2011, disease activity is still at relatively increased levels throughout the state. Visit the California Department of Public Health website for the most recent information.
• In Michigan, an increase in pertussis was first observed in the second half of 2008, continued throughout 2009, and continued throughout 2010. This is on top of a long term rising trend in the reported number of pertussis cases since about 1990. In 2010 there were 1,564 cases. In 2009 (for the complete year) there were 902 cases reported. In 2008 there were 315 cases reported. Visit the Michigan Department of Community Health website for the most recent information.
• In Ohio, Columbus Public Health (CPH) and Franklin County Board of Health (FCBH) responded to an outbreak of pertussis during 2010 and 2011. In 2010, there were 964 cases reported by Columbus and Franklin Counties. This is the most cases reported in 25 years. Through April 9, 2011, 144 cases of pertussis were reported. For the most recent information, visit the Columbus Public Health web site.

Outbreak Articles

• Notes from the Field: Pertussis — California, January–June 2010
  MMWR June 9, 2010; 59(26):817
• Use of Mass Tdap Vaccination to Control an Outbreak of Pertussis in a High School — Cook County, Illinois, September 2006–January 2007
  MMWR July 25, 2008;57(29):796-9
• Outbreaks of Respiratory Illness Mistakenly Attributed to Pertussis — New Hampshire, Massachusetts, and Tennessee, 2004–2006
  MMWR August 24, 2007; 56(33):837-842
• Pertussis Outbreak in an Amish Community — Kent County, Delaware, September 2004–February 2005
  MMWR August 4, 2006;55(30):817-21
• Outbreaks of Pertussis Associated with Hospitals — Kentucky, Pennsylvania, and Oregon, 2003
  MMWR January 28, 2005;54(3):67-71
• School-Associated Pertussis Outbreak — Yavapai County, Arizona, September 2002–February 2003
  MMWR March 19, 2004;53(10):216-9
• Pertussis Outbreak among Adults at an Oil Refinery — Illinois, August–October 2002
  MMWR January 10, 2003;52(01):1-4

Resources

• Surveillance Manual's Chapter on Pertussis
  Manual from the Surveillance of Vaccine-Preventable Diseases textbook.
• CDC and CSTE Case Definition for NNDSS
• Guidelines for the Control of Pertussis Outbreaks
• Outbreak Control, Surveillance Manual's Chapter on Pertussis
  Manual from the Surveillance of Vaccine-Preventable Diseases textbook
• For Parents and Patients
  What parents need to know, e-cards, flyer (protect yourself and your baby), hear the cough...