NUR 4430 Module 3 Outbreak Investigation Paper Example

Seven Coughs in Grade Seven: Walking a School Pertussis Cluster Through the Steps of an Outbreak Investigation

Student Name

Bachelor of Science in Nursing, Thomas Edison State University

NUR-4430: Public Health Nursing

Mentor Name

Month Day, Year

Seven Coughs in Grade Seven: Walking a School Pertussis Cluster Through the Steps of an Outbreak Investigation

In late October, the school nurse at a middle school in Cumberland County called the county health department about a cough. Three seventh graders had been out for more than a week with coughing fits, and one parent mentioned that a doctor had ordered a pertussis test. Within ten days the count reached seven. This paper follows that composite cluster through the steps of an outbreak investigation laid out in the federal field epidemiology course (Centers for Disease Control and Prevention, 2012), and explains at each step what the public health nurse contributed. The students, school and dates are invented for teaching, while the disease facts and the evidence cited are real.

Preparing, Verifying and Confirming

The health department's first tasks were to prepare for fieldwork and to make sure there really was a problem. Preparation meant pulling the case report form, checking that the communicable disease nurse and the school nurse could talk daily, and confirming with the department's medical consultant how laboratory results would be interpreted. Verification meant obtaining the results: two of the first three students had positive polymerase chain reaction tests for Bordetella pertussis, and the third had a classic clinical picture of paroxysmal cough with an inspiratory whoop.

Confirming an outbreak means showing that the number of cases exceeds what is normally expected. The county usually records a handful of pertussis cases a year, spread across ages and towns. Seven cases in one grade at one school within a month is clearly above that baseline. The nurse documented that comparison in the investigation notes, because a cluster that is simply a busy month for an endemic disease calls for a different response than a true outbreak.

Case Definition and Case Finding

A case definition sets the rules for who is counted. The team adopted a working definition with three tiers. A confirmed case was a person linked to the school with a cough of any length and a positive laboratory test. A probable case had a cough lasting at least two weeks with paroxysms, whoop or post-cough vomiting and no other diagnosis. A suspected case had a cough of at least one week with an epidemiologic link to a confirmed case. Using tiers kept the count honest; mixing laboratory-confirmed children with every coughing classmate would have inflated the outbreak and made it hard to judge whether control measures were working.

Case finding was where the public health nurse did most of the work. With the school nurse, the county nurse reviewed attendance records for absences of three or more days, sent a letter home in English and Spanish asking families to report any cough lasting more than a week, and called pediatric offices in the area to ask for any recent pertussis tests. That search found four more students and one teacher meeting the probable or confirmed definition, along with a toddler sibling of a confirmed case. The sibling mattered most, because infants and toddlers carry the greatest risk of severe disease.

Describing Time, Place and Person

The cases were then described by time, place and person. Plotted by date of cough onset, the cases formed a curve rising over three weeks with no single sharp peak, which is what a germ passed between classmates produces, as opposed to the tall narrow spike left by one contaminated meal. By place, all student cases were in the seventh grade and five shared the same science and math sections. By person, the students were eleven and twelve years old, and all had records showing five doses of DTaP vaccine in early childhood; four of the seven had also received the Tdap booster recommended at age eleven or twelve, but only within the previous few months.

That last finding pointed toward a known explanation. Klein et al. (2012) compared children aged four to twelve who tested positive for pertussis with children who tested negative and found that the odds of pertussis rose by about 42 percent for each year after the fifth DTaP dose, indicating that protection from the acellular vaccine wanes over the following years. A seventh-grade cohort that is several years past its last childhood dose and only partly boosted is exactly the group the evidence would predict. The description therefore produced a hypothesis: transmission within shared classrooms among students with waning vaccine protection.

Control Measures and Communication

Control measures were put in place before the investigation was finished, as is usual for a disease that spreads easily. Following national guidance on pertussis summarized in the federal vaccine-preventable disease reference (Centers for Disease Control and Prevention, 2024), confirmed and probable cases were excluded from school until they had completed five days of an appropriate antibiotic. Antibiotic prophylaxis was recommended for household contacts and for close contacts at high risk of severe illness or likely to expose someone who is, including the household with the toddler and a teacher who was pregnant. The health department ran a Tdap catch-up clinic at the school for students due for the booster and for staff.

Communication shaped how well those measures worked. The nurse drafted a letter for families explaining the symptoms, the exclusion rule and the clinic dates, in plain language, and met with the principal to explain why the measures were proportionate. Skoff et al. (2015) found that siblings had become the most common identified source of infant pertussis infection in the United States, ahead of mothers, which gave the letter a concrete reason to urge families with babies at home to watch for coughing older children. No new cases with onset more than three weeks after the last control measure were identified, and the outbreak was closed after two incubation periods without new onsets.

Reflection

Outbreak investigation can look like a checklist, but in this cluster each step depended on the one before. A loose case definition would have made the epidemic curve meaningless; incomplete case finding would have missed the toddler; a weak description would have produced no hypothesis about waning protection. The public health nurse's role ran through all of it, from the phone call that started the investigation to the letter that ended it, and that continuity is a good illustration of what population-focused nursing looks like in practice.

References

Centers for Disease Control and Prevention. (2012). Principles of epidemiology in public health practice: An introduction to applied epidemiology and biostatistics (3rd ed.). https://archive.cdc.gov/www_cdc_gov/csels/dsepd/ss1978/index.html

Centers for Disease Control and Prevention. (2024). Pertussis. In Epidemiology and prevention of vaccine-preventable diseases (Pink Book). https://www.cdc.gov/pinkbook/hcp/table-of-contents/chapter-16-pertussis.html

Klein, N. P., Bartlett, J., Rowhani-Rahbar, A., Fireman, B., & Baxter, R. (2012). Waning protection after fifth dose of acellular pertussis vaccine in children. New England Journal of Medicine, 367(11), 1012-1019. https://doi.org/10.1056/NEJMoa1200850

Skoff, T. H., Kenyon, C., Cocoros, N., Liko, J., Miller, L., Kudish, K., Baumbach, J., Zansky, S., Faulkner, A., & Martin, S. W. (2015). Sources of infant pertussis infection in the United States. Pediatrics, 136(4), 635-641. https://doi.org/10.1542/peds.2015-1120