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G335 Post immunisation pyrexia - what are we doing?
  1. FA Baxter,
  2. A Bilkhu,
  3. C Hathorn,
  4. M Lamoudi
  1. Acute Receiving Unit, Royal Hospital for Sick Children, Edinburgh, UK


Aim To identify the number of infants admitted to our hospital with pyrexia post-immunisations, investigations performed, length of stay and antibiotic usage.

Methods We conducted a retrospective audit of infants presenting with fever post-immunisation to the emergency department (ED) at our children’s hospital between March and October 2016. Electronic patient records were accessed to review demographic and clinical details.

Results Forty-three infants presented with a history of fever post-immunisation, aged 6 to 36 weeks. The majority (81%) presented after 2 and 4 month immunisations. Mean temperature on arrival was 38.1 °Celcius (range 36.6–39.7).

Twenty-nine (67%) infants were discharged home from ED, of whom 23 (79%) had no investigations. The remaining 6 infants had FBC (mean WCC 19.6, range 14–28), CRP (mean 19, range 4–30) and blood cultures (one Staphylococcus epidermidis, others negative).

Fourteen (33%) infants were admitted to hospital, all of whom had investigations. Mean CRP in this group was 27 (range 1–97), mean WCC 14 (range 3–26). One blood culture grew Staphylococcus capitis, others were negative. Thirteen infants had urine samples taken, of which one grew Escheria Coli. Seven infants had lumbar punctures, one was positive for Enterovirus, all CSF cultures were negative. Twelve had bacterial and viral throat swabs, 6 had bacterial and viral stool samples, the results of which did not change management. Seven infants received intravenous antibiotics, and mean length of stay was 2 days (range 1–5).

Conclusions Fever post-immunisation is a frequent occurrence, and carers are encouraged to administer regular paracetamol after meningococcal B vaccination in particular. Of those presenting to ED, 47% had investigations performed, the results of which may encourage admission to hospital, due to raised inflammatory markers. Of the 20 infants in our cohort, only one had a proven bacterial infection requiring treatment, while 7 received antibiotics

We suggest that blood tests are a poor discriminatory marker of bacterial infection in this population, as raised inflammatory markers are to be expected post-immunisation. Clinical suspicion of infection must remain high, but decisions to admit and observe, or treat with antibiotics should be made on an individual clinical basis.

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