Inclusion Criteria:  Followed for hemopathy or cancer, Presenting with post-chemotherapy NF, With social security coverage, With parents able to provide appropriate home supervision, Consent of parents and child if able to give consent.  Exclusion Criteria:  NF to diagnosis of tumor disease, Child with palliative care, Child who has had an allogeneic hematopoietic stem cell transplant within the past year, NF immediately following an autologous hematopoietic stem cell transplant, Participation in the study during a previous NF, Curative antibiotic therapy or documented infection prior to admission, Initial management at a non-investigative center, Refusal of the child or parents to participate  Translated with www.DeepL.com/Translator (free version)