Background From September 2015 babies born on or after 1/7/15 are being offered the MenB (meningococcal group B) vaccine, bexsero, as part of their routine immunisation schedule. The vaccine is given at 2, 4 and 12 months.

Fever is a common and predictable response to vaccinations. In clinical studies when bexsero was given alone, the frequency of fever was 44%-59%. This number rose to between 69–79% when bexsero is co-administered with routine vaccinations.

Babies are routinely being given paracetamol at the time of immunisation and parents advised to administer two further of doses at 4–6 hly intervals.

Other very common side effects include loss of appetite, sleepiness and irritability.

Aim I aimed to quantify the number of infants presenting to ED with fever post-immunisations and collect data on how they are being managed.

Method A retrospective analysis of records was undertaken between 1/9/15–14/10/15 to identify those <3mths of age presenting with problems relating to recent immunisation.

Results 37 infants were seen over the 6 week period with parental concern of fever. 8 had recently received the MenB vaccine. 5 infants presented within the first 12hrs and the rest 12–18hrs post immunisation.

All 8 were given paracetamol prior to attendance.

3 babies were febrile >38 degrees on arrival. 4 babies were discharged after review including one with a documented temperature. 4 were admitted to hospital, 3 of whom underwent a full septic screen including LP and were commenced on IV antibiotics. Investigations including CSF, blood and urine cultures for all 3 of these infants were negative and their fever was attributed to recent vaccinations.

Conclusion The clinical management of babies presenting with fever post-immunisations ranged from reassurance to full septic screen and hospital admission. Isolated fever in an otherwise well baby may be assessed fit for discharge. However, when combined with other common side effects such as irritability and poor feeding, investigation to exclude alternative cause for symptoms may be deemed necessary. This must be assessed on a case by case basis but the author suggests admission for observation be considered an appropriate management strategy for "well" infants.