Pertussis Cases Increasing in San Diego County
October 25, 2013
The San Diego County health department has confirmed 202 local cases of pertussis so far in 2013, compared to 127 cases reported at this time last year. One local high school site has had thirteen reported cases: all were students 14–16 years old up-to-date on vaccinations with symptom onset dates between August 14 and September 27. When cases occur in schools or daycares, staff and families are routinely notified and urged to seek care promptly for early symptoms or for contact prophylaxis. Clinicians who evaluate patients with respiratory symptoms should inquire about recent possible exposures in schools or community settings and consider pertussis despite vaccination status.
A diagnosis of pertussis is often challenging in young infants given that the cough may be undetectable or mild and fever is usually not present. Mild illness may quickly transform into respiratory distress and include apnea, hypoxia, or seizures. Delays in treatment may increase the risk of fatal illness in young infants, especially if the infant is <3 months of age. A white blood cell count of ≥20,000 cells/mm3 with ≥50% lymphocytes is a strong indication of pertussis. Adults and adolescents with an unexplained cough illness lasting more than two weeks should be evaluated for pertussis.
When pertussis is in the differential, a nasal aspirate (preferable) or nasopharyngeal swab should be obtained for PCR testing and/or culture (available at reference laboratories). Serologic tests are not recommended. All suspected or confirmed cases should be promptly reported to the San Diego County Immunization Program via Confidential Morbidity Report (CMR) by FAX to (619) 692-5677 or by calling at (866) 358-2966 (select option #5).
Suspected and confirmed pertussis cases should be promptly treated with azithromycin and closely monitored. Clinicians are strongly encouraged to initiate antibiotic treatment prior to test results in patients whose clinical history is suggestive of pertussis or who are at risk for severe complications.
Post-exposure prophylaxis (PEP) should be provided to all household contacts, caregivers, and other persons who have had direct contact with respiratory, oral, or nasal secretions from a symptomatic case. Click here for more information about pertussis treatment and PEP. Patients under treatment for pertussis should remain at home until 5 days of appropriate treatment are completed. Contact with infants and others susceptible to the disease should be avoided during this time.
Children should receive 5 doses of DTaP by kindergarten: one dose at 2, 4, 6 and 15–18 months, and 4–6 years. A Tdap booster is recommended for adolescents at age 11 or 12, and for adults <65 years of age who have not yet received a booster. As part of the “cocooning” strategy, all close contacts of infants (e.g., parents, siblings, grandparents, child care providers, etc.) and all healthcare workers should be immunized against pertussis with Tdap or DTaP vaccine, as age appropriate. Pregnant women should be vaccinated during 27–36 weeks gestation during each pregnancy, irrespective of the patient’s prior history of receiving Tdap.