Similar to the approach used in our previous review, we performed a computer search of the scientific literature (in English and other languages) published from January 2000 through June 2004 using the words rotavirus and the truncated stem rota-. We restricted the analysis to studies that met the following criteria: 1) were initiated after 1993; 2) were conducted for at least 1 full calendar year; and 3) examined rotavirus among at least 100 children <5 years of age hospitalized with diarrhea.
For each study, we determined the proportion of cases positive for rotavirus among children hospitalized with diarrhea. We plotted this proportion against the per capita gross national product (GNP) for the country in which the study was conducted. We then classified countries by per capita GNP into World Bank income groups (low, <US $756; low-middle, US $756–$2,995; high-middle, US $2,996–$9,265; and high, >US $9,265) (10
), and calculated the median (interquartile range [IQR]) proportion of diarrhea hospitalizations attributable to rotavirus for each income group.
We next calculated an overall median detection rate by taking a weighted average of the median detection rates for each of the income groups. The weights assigned to each income group corresponded to the proportion of deaths from childhood diarrhea among countries in that income group as determined on the basis of our previous analysis (2
): 85% in low-income countries, 13% in low-middle–income countries, 2% in high-middle–income countries, and <1% in high-income countries. To estimate deaths from rotavirus disease among children, we multiplied the overall median detection rate of rotavirus among children hospitalized with diarrhea by a recent World Health Organization estimate of deaths from diarrhea among children worldwide (5
We abstracted information from 41 studies that met all the inclusion criteria (). Unlike the previous review of studies conducted for the period 1986–1999, in which the proportion of diarrhea-related hospitalizations attributable to rotavirus showed a distinct increasing trend with increasing income level, we found that the median detection rates increased only slightly with increasing income level (). The median detection rate for rotavirus among children hospitalized with diarrhea was 39% in studies conducted in low-income countries, 40% for low-middle–income countries, 38% for high-middle–income countries, and 44% for high-income countries, for an overall weighted median estimate of 39% ().
Figure 1 Percentage of severe diarrhea cases attributable to rotavirus for countries in different World Bank income groups, by per capita gross national product (GNP), for studies published in 1986–1999 and 2000–2004. GNP is in US dollars. Upper (more ...)
Percentage of diarrhea hospitalizations attributable to rotavirus for countries in different World Bank income groups, 1986–1999 and 2000–2004
If we multiply the greater median rotavirus detection rate of 39% (IQR 29%–45%) from this analysis by 1,566,000 recently estimated childhood diarrhea deaths (5
), we find that rotavirus causes ≈611,000 childhood deaths (IQR 454,000–705,000). More than 80% of all rotavirus-related deaths were estimated to occur in low-income countries of south Asia and sub-Saharan Africa ().
Estimated global distribution of rotavirus-related deaths. Each dot represents 1,000 rotavirus-related deaths.