Table 2.

Studies on viral etiology of acute asthma

	Wheezing episodes/control subjects		Viral identification rates (%)
Year of studya		Age (y)	RSV	Rhinovirus	Enteroviruses	Parainfluenza virus	Influenza A/B virus	Adenovirus	Coronavirus	hMPV	Total positive
1995 [15]	161	9–11	4	50b		7	7		13		80c
1999 [10]d	48/42	2–16	6/0	71/36e	2/0		2/0	2/0	6/0		83
1999 [16]	71	≤2	24	44	10f	4f	10f	5f	5f		86
	61	>2	18	51							77
2003 [17]	179	0.1–17	7	79		1	2			2	88
2004 [13], [14]g	49/17	0.4–3	22	27/0	33/0	4	4	12	0	0	90
	65/25	3–16	8	31/0h	38/0h	9	2	2	2	0	91

Abbreviations: hMPV, human metapneumovirus; RSV, respiratory syncytial virus.

^aIncluding studies using polymerase chain reaction with a sampling period of >1 year.

^bNumber is for picornaviruses, of which 57% were rhinoviruses, the remaining viruses could not be cultured and were classified as rhinoviruses because most enteroviruses culture easily.

^cIn reported falls in peak expiratory flow.

^dChildren with wheezing were included. Excluded were children with bronchopulmonary dysplasia or using corticosteroids within the previous week.

^eWith polymerase chain reaction; 18/24% using culture only.

^fInformation not available of different age groups.

^gNew subgroup analyses.

^hNontypable rhino-enterovirus: 12/18 in children age <3 y and 17/12 in children age ≥3 y.