Table 1. Background characteristics, incidence of symptomatic rotavirus infections per personyear of observation for children <2 years and bias assessment of 21 prospective studies included in the meta-analysis.

ref	country (location)	inc	year of study (midpoint)	study group/situation	ses	bias
[18]	Canada (Winnipeg, Manitoba)	0.24	1977	mothers in early postpartum period recruited at Health Sciences Centre; not biased toward high socioeconomic class	NL	P
[41]	Mexico (San Pedro Martir, around the southwestern outskirts of Mexico City)	0.38	1988	low income periurban area	L	N
[42], [67]	Nigeria (Ibadan)	1	NR	children born at a General Hospital; lower socioeconomic class	L	H
[43]	Chile (Población Carlos Condell slum, City of Santiago)	0.19	1981	all families with children <7years age living in slum	L	P
[44]	Mexico (rural village appr 180 km southwest of Mexico City)	0.33	1983	all children from the village	U	P
[45]	Guinea-Bissau (suburban districts Bandim II and Bele of Bissau)	0.24	1997	houses were randomly selected	PL	N
[46]	Central African Republic (Bangui)	0.14	1985	children in maternity ward (living in neighbourhood of the ward)	PL	H
[47]	Argentina (Avellaneda District, a suburb of Buenos Aires)	0.13	1984	families recruited when seeing pediatrician at Primary Health Care Center; low socioeconomic level, shantytowns, unstable and overcrowded houses	L	H
[48]	Guatemala (Cauqué)	0.84	1967	Mayan Indians; crowded	L	N
[49]	Bangladesh (Mirpur, Dhaka)	0.25	2003	urban slum	L	P
[50]	US (Northern Virginia)	0.22	1978	patients from a group pediatric practice; middle-class suburban population	NL	H
[51]	Palestina (Gaza: Jebaliya)	0.08	1985	crowded, poor	L	P
[52]	Costa Rica (Puriscal)	0.06	1983	children born in Hospital San Juan de Dios in San José (97% of babies from Puriscal are born here)	NL	N
[53]	China (suburb of Hong Kong)	0.06	NR	low- to low-middle income families	U	H
[54]	Nicaragua (Léon)	0.23	1992	children born in university hospital of whom mothers lived in one of the 3 health areas in the city	NL	N
[55]	Bangladesh (10 villages in Mirzapur, rural area appr 60 km from Dhaka)	0.21	1994	door-to-door census; crowded, poor	L	N
[56]	Egypt (2 villages in the vicinity of a rural district appr 40 km from Alexandria)	0.29	1995	house-to-house census	U	N
[57]	Bangladesh (Enayet Nagar and Sepai Kandi)	0.41	1978	Matlab field research area	L	H
[58]	Egypt (Epidemiology Study Center Field research area near Bilbeis)	0.21	1982	8 villages were selected in the Epidemiology Study Center field research area	U	N
[59]	Gambia (Bakau)	0.51	1982	representative 55% sample of locally born children	PL	H
[60]	Brazil (peripheral area of Belem)	0.22	1984	poor housing, low socioeconomic level	L	N

Inc: incidence; SocioEconomic Status (ses): low (L: study group living in poor, crowded area), probably low (PL: studies performed in developing countries), not low (NL: studies performed in developed countries) or unclear (U). NR: not reported, N: no high risk of bias, P: possible high risk of bias and H: high risk of bias in the reported incidences.

¹children were followed for the first year of life only.