The aim of this pilot study is to demonstrate the feasibility of viral biomolecular diagnosis in sputum compared to nasopharyngeal swab in cystic fibrosis acute respiratory infection.

In cystic fibrosis (CF), patients face polymicrobial airway infections. Besides bacteria, viruses are now also considered as important agents in lung function deterioration. No strategy has been established on the optimal sampling for respiratory viral molecular diagnostic in CF. Nasopharyngeal swabs (NP) are recommended for respiratory viral screening in non-CF patients but are invasive and sometimes painful for patients. As sputa are non invasive and collected for bacterial monitoring in CF patients they could represent a convenient alternative to NP swabs.

This study's aim is to define whether viral screening give concordant results between sputa and NP swabs.

Inclusion Criteria:

• Participant with Cystic Fibrosis
• Participant able to expectorate
• Participant with sign of acute respiratory infection

Exclusion Criteria:

• participant not able to expectorate
• patient refusing to participate

participant living with cystic fibrosis disease cared in french pediatric or adult CRCM