A 10-week-old male infant presented multiple times to a United Kingdom (UK)hospital with prolonged fever for one month, occurring at irregular intervals and in the absence of any other noticeable symptoms. He was the first child of non-consanguineous, Nigerian parents, with neither parent having traveled outside the UK for two years prior to pregnancy. Routine antenatal serology and scans were unremarkable, and the mother was well during pregnancy with no febrile illnesses or health concerns reported. The boy was born at term via elective cesarean section due to breech positioning (birth weight 3.75 kg), with an uncomplicated perinatal period. He received the BCG vaccine at 6 weeks of age as standard care due to having parents born in a country with high rates of tuberculosis, but was otherwise unvaccinated; his initial 8-week vaccinations were delayed because he was febrile.