Disseminated Adv infections are associated with high morbidity and mortality in HSCT pediatric patients. The most common source of Adv infection after pediatric HSCT is the host digestive tract where latent Adv are reactivated after engraftment. We have shown in a monocentric study that Adv viral load in stools is a predictive factor of blood infection in children with digestive Adv infections. We assume that an early treatment, with antiviral drugs, such as cidofovir and brincidofovir, may avoid severe Adv infections and diseases and thus that molecular surveillance in stool is a critical factor for the control of Adv reactivations.

The study has two main objectives: (i) confirming the impact of Adv viral load in stools on the occurrence of blood infection based on a multicentric prospective cohort study design; and (ii) determining the prognostic and predictive factors for efficacy and toxicity of antiviral drugs, such as brincidofovir and cidofovir.

Inclusion Criteria:

• Allogeneic hematopoietic stem cell transplantation from any donor other than full-matched related donor
• Age above 2 months and under 20 years
• Provide written informed consent from the parents (if <18) and child
• Free, informed and written consent, signed by the patient and investigator before any Study examination. If the patient is a minor by child (if possible) and both parents or child and the legal representative in case only one parent is alive

Exclusion Criteria:

• Hematopoietic stem cell transplantation from full-matched related donor
• Females who are pregnant or currently nursing
• Any patient receiving cidofovir, ribavirin or any other anti-viral drug under development given in order to treat or prevent
• Current disease attributed to adenovirus infection
• Lack of affiliation to a social security scheme (as a beneficiary or assignee).Current disease attributed to adenovirus infection

any patient age above 2 month- and under 20 year- old receiving an allogeneic hematopoietic stem cell transplant