Inclusion criteria:  Inclusion age less than 16 years Inclusion age > 3 months of actual age for term infants and > 3 months for former preterm infants. Documented severe infection (bacterial, viral, fungal) at the University Hospital Center of Montpellier, Toulouse or Marseille Severe infections concerned by the study: any infection requiring hospitalization in pediatric intensive care (more than 24 hours) including: meninges or brain lesions, pleuro-pneumopathy, any infection associated with sepsis and/or an opportunistic germ, septic shock, etc. Encephalitis and encephalomyelitis of infectious origin Child benefiting from a social security system Collection of parental/legal representative consent  Exclusion criteria:  Undocumented severe infections Acute bronchiolitis Children admitted with isolated SRV bronchiolitis without further complications from the infection; Previous comorbidity explaining the infection and/or stay in ICU/Continuing Care: Primary or known secondary immune deficiency; burns; risk factors for non-infectious epilepsy (encephalopathy, known epilepsy, head trauma), pneumonia caused by swallowing disorders or tracheotomy or chronic lung disease, asthma, meningitis favored by cochlear implants, breach of blood-brain barrier or neuromeningetic material, deep infection on implanted material or within 48h after surgery, cardiovascular decompensation; any other chronic conditions that may contribute to infection; Inability to obtain consent from parents/legal guardians.