The Indiana State Department of Health (ISDH) is investigating increased pertussis activity in District 5.  Letters have been sent home with students in schools in Hamilton and Shelby counties to describe the symptoms of pertussis, when to see a health care provider, and the importance of vaccination.  Health care providers are encouraged to consider a diagnosis of pertussis in patients with cough illness.

Pertussis Clinical Case Definition

A cough illness lasting at least 2 weeks with one of the following: paroxysmal cough, inspiratory whoop, or post-tussive vomiting, without other apparent cause.  Symptoms typically begin 7-10 days following exposure. Pertussis occurs in three stages: First, an individual may experience cold-like symptoms, including a runny nose or sneezing. A mild, occasional cough may develop as well. During the second stage, the cough becomes more severe with bursts of coughing that may cause difficulty catching ones breath (resulting in a whoop sound) or vomiting following coughing. The second stage can last as long as 10 weeks. Finally, the cough begins to resolve and become less persistent during the third stage.

Laboratory Testing

Please order appropriate testing in suspect pertussis cases (i.e. those meeting the clinical case definition for pertussis or those with a coughing illness of any duration with exposure to a pertussis case). Appropriate testing includes culture and/or PCR. Note that the ISDH has DFA/culture kits available for use in testing suspected cases; kits can be obtained by following the contact instructions in the document linked below. PCR testing is also acceptable if available from another laboratory. The ISDH discourages clinicians from using serologic tests for diagnosis of pertussis as commercial tests available have not been validated.

Antibiotic Therapy

If you suspect a pertussis case, do not wait for laboratory confirmation to initiate antibiotic therapy. Prophylactic antibiotic therapy should also be prescribed for all household contacts regardless of whether or not they are symptomatic and regardless of immunization status. For a chart depicting appropriate antibiotic therapy for both cases and contacts, visit http://www.in.gov/isdh/files/RecommendedPertussisControlMeasures2006(1).pdf Note that antibiotics will shorten the infectious period of pertussis, but they will not shorten the duration of symptoms unless provided very early in the course of illness.

Control Measures

Suspect cases should be excluded from work or school through 5 days on an appropriate antibiotic. If a suspect case is not treated, the case should be excluded through 21 days after cough onset.  Symptomatic contacts should be excluded from work or school through 5 days on an appropriate antibiotic. Symptomatic contacts that are not treated should be excluded through 21 days after cough onset. Asymptomatic contacts should be placed on antibiotics, but they may immediately return to work or school. One exception: inadequately immunized household contacts under the age of 7 should be excluded through 5 days on antibiotics per the Indiana Communicable Disease Rule.  Assess the vaccination status of patients. Children under age 7 are eligible for the DTaP vaccine, and persons ages 10 through 64 are eligible for the one-time Tdap pertussis booster vaccine. Vaccination following exposure will not prevent illness; however, it will help to protect against future exposures. Note that individuals who have been fully vaccinated against pertussis can still develop the illness, but it tends to be milder than in unvaccinated individuals.