Table 4.

Data Presented in Birth Cohort Studies Relating to Child Age and Risk for Norovirus Disease

Birth Cohort [Reference]	0–5 mo	6–11 mo	12–24 mo
Perua [24]	103 infections per 100 child-years; 29 episodes of norovirus-associated diarrhea per 100 child-years; 55% (66/119) of infections were asymptomatic	188 infections per 100 child-years; 79 episodes of norovirus-associated diarrhea per 100 child-years; 36% (73/202) of infections were asymptomatic	84 episodes of norovirus-associated diarrhea per 100 child-years
MAL-EDb [29]	154 GI or GII infections per 100 child-years	221 GI or GII infections per 100 child-years; 71% of infections and 82% of norovirus-associated diarrhea reported among children at least 6 mo of age	216 GI or GII infections per 100 child-years
Ecuadorc [28]	5 infections per 100 child-years	76 infections per 100 child-years	64 infections per 100 child-years
India [20]		26 episodes of norovirus-associated diarrhea per 100 child-years occurred among children 12 mo or younger; median age of children experiencing norovirus-associated diarrhea was 7 mo (IQR, 4.5–12 mo)	9 episodes of norovirus-associated diarrhea per 100 child-years occurred among children in the second year of life
Chiled [23]	68 asymptomatic norovirus infections per 100 child-years	100 asymptomatic norovirus infections per 100 child-years; episodes of norovirus-associated diarrhea were similar for all 3 age categories	48 asymptomatic norovirus infections per 100 child-years
Brazil [17]		Children experienced first episode of norovirus-associated diarrhea by 10 mo of age on average (range, 7–11 mo)

Abbreviations: GI, genogroup I; GII, genogroup II; IQR, interquartile range; MAL-ED, Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development.

^aIncidence estimates reported here were calculated from the incidence per 100 child-months reported in the manuscript.

^bSum of GI and GII incidence estimates reported here were calculated from individual GI and GII incidence per 100 child-months reported in manuscript. To derive the incidence estimates reported for the 12–24-mo age category, the sum of incidence estimates for the age categories of 12–17 and 18–24 mo were used. Since only percentages of infections and diarrhea were reported in manuscript, the fraction of children infected that were at least 6 months of age over the total number of children infected could not be derived.

^cThe table heading 12–24 months includes data reported for children aged 12–23 months.

^dIncidence estimates reported here were calculated from incidence per child for 6 months (semester) of life. Also, data presented for age categories of 0–6, 7–12, and 13–18 months are listed under table headings of 0–5, 6–11, and 12–24 months, respectively.