These results were also compared with RSV specific detection. All nasopharyngeal mPCR and RSV tests requested by clinicians in our French teaching hospitals group between and were retrospectively included.
All repeated samples for the same children in the same month were discarded. Of the mPCR tests children performed, Viral distribution showed strong variations across ages. It emphasizes the number of undiagnosed respiratory viruses according to the current diagnosis practice in France and gives a better picture of respiratory viruses identified in hospital settings by mPCR all over the year in France. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
However these data are secured in our laboratory system, as required by the ISO certification of our laboratory, and can be shared on request approved by an adequate ethical committee. Any request can be sent to the corresponding author at the following email: benoit.
Competing interests: The authors have declared that no competing interests exist. Acute respiratory tract infections ARTIs are a major worldwide cause of morbidity and mortality in childhood. Respiratory viruses are the most common cause of such infections and the introduction of molecular detection techniques has considerably improved the detection of these pathogens. Indeed, new multiplex PCR tests now allow a fast detection of a wide range of respiratory viruses [ 1 ] including recently described viruses as human metapneumovirus [ 2 ], human bocavirus [ 3 ] and coronavirus NL63 [ 4 ] or HKU1 [ 5 ].
Molecular tests also changed the understanding of some older respiratory viruses group such as for rhinovirus, commonly associated only with the common cold and now described as providing severe ARTIs in young children [ 6 β 8 ]. Despite these new knowledges only a few respiratory viruses, such as RSV or metapneumovirus, have been well established as highly pathogenic [ 9 , 10 ]. The causative role of other respiratory viruses is still discussed, mainly as they can be also detected in asymptomatic patients, especially during childhood [ 11 β 14 ].
