Table 2.

The respiratory viruses detected in infants during acute respiratory infections

Virus	Seasonality	Risk factors for severe disease
Adenovirus	Throughout the year	Young age (in utero transmitted disease)
Bocavirus‐1	Moderate winter seasonality	Pre‐existing medical condition, nosocomial disease
Coronavirus	Marked winter seasonality	Prematurity
Enteroviruses	Marked late summer and early fall seasonality	Young age (in utero transmitted disease)
Metapneumovirus	Marked winter seasonality	Prematurity, young age, pre‐existing severe medical condition, nosocomial disease
Parechovirus	Moderate winter seasonality	Prematurity
Influenza A, B	In temperate zones, annual epidemics during winter months	Prematurity, CLD
Parainfluenza 1–4	Moderate spring seasonality	Prematurity
Respiratory syncytial virus	Annual winter outbreaks	Prematurity, CLD, CHDa, CF, congenital immune defects, neuromuscular disorders
Rhinovirus	Through the year, especially during early fall and spring	Prematurity, diseases affecting lung function
Virus	The most common clinical signs in neonates	Acute complications
Adenovirus	Nonspecific febrile illness – sepsis‐like disease, rhinorrhea, congestion, cough, temperature instability, poor feeding, neurologic signs (irritability, lethargy)	Pneumonia, disseminated disease
Bocavirus‐1	Rhinorrhea, congestion, cough, bronchiolitis, fever	Pneumonia, AOM, meningoencephalitis
Coronavirus	Rhinorrhea, congestion, cough, bronchiolitis, fever, apnoeas	Pneumonia, CNS manifestations (febrile convulsions, meningoencephalitis), laryngitis
Enteroviruses	Nonspecific febrile illness – sepsis‐like disease, respiratory symptoms (pharyngitis, bronchiolitis), skin symptoms (hand‐ foot‐ and mouth disease exanthema), G‐I symptoms (stomatitis, herpangina, vomiting, diarrhoea)	Virussepsis, meningoencephalitis, perimyocarditis, hepatitis, coagulopathy, myositis, pneumonia
Metapneumovirus	Rhinorrhea, congestion, cough, bronchiolitis, fever, apnoeas, acute respiratory failure	Pneumonia, AOM
Parechovirus	Nonspecific febrile illness – sepsis‐like disease, mild respiratory or G‐I symptoms	Meningoencephalitis, virussepsis, AOM
Influenza A, B	Respiratory distress, temperature instability, sepsis‐like disease	AOM, pneumonia, laryngitis, CNS manifestations, myocarditis, myositis
Parainfluenza 1–4	Rhinorrhea, congestion, cough, bronchiolitis, fever	Pneumonia
Respiratory syncytial virus	Rhinorrhea, congestion, cough, bronchiolitis, fever, apnoeas, acute respiratory failure	Pneumonia, AOM, rarely: meningoencephalitis, perimyocarditis, hepatitis
Rhinovirus	Rhinorrhea, congestion, cough, irritability, fever, sepsis‐like disease	Pneumonia, AOM
Virus	Prognosis	Long‐term sequelae
Adenovirus	Usually good. Mortality is high in neonates with pneumonia (50%) and disseminated disease (75%)	No data available
Bocavirus‐1	Good	Adverse neurological sequelae have been reported after encephalitis
Coronavirus	Usually good	No data available
Enteroviruses	Usually good, but can be fatal. Virussepsis caused by coxsackievirus B or echovirus has a high mortality (50%)	May act as an environmental trigger for type 1 ‐diabetes. Persistent hepatic and cardiac dysfunction and neurodevelopmental deficits have been reported after severe enterovirus disease
Metapneumovirus	Usually good	No data available
Parechovirus	Usually good	Parechovirus‐3 encephalitis is shown to be associated with CNS white matter changes and with adverse neurodevelopmental long‐term sequelae
Influenza A, B	Usually good. Can be fatal	No known long‐term sequelae
Parainfluenza 1–4	Usually good	No data available
Respiratory syncytial virus	Usually good. Can be fatal	Recurrent wheeze, asthma, asthma, allergic sensitisation
Rhinovirus	Usually good. Can be fatal	Recurrent wheeze, asthma

AOM = Acute otitis media; CNS = Central nervous system; CLD = Chronic lung disease; CHD = Congenital heart disease; CF = Cystic fibrosis; G‐I = Gastrointestinal.

^aClinically significant congenital heart disease.