a comprehensive literature search of published studies indexed in global and databases in china during 19952010 was conducted . initially , 125 reports published in english and 223 in chinese concerning the seroprevalence in mainland china were identified . among them , 85 articles published in england and 178 articles published in china were excluded after title and abstract screening . after reading the full text , we excluded another 33 english and 26 chinese articles . finally , 26 publications were included in this systematic review and have been summarized in technical appendix table 1 . these studies were cross - sectional and were conducted in 8 of the 34 provinces . a substantial number ( 35.5% ) of these studies most samples tested were serum or plasma with few exceptions ( 1 whole blood , 1 peripheral blood mononuclear cells ) ; sample sizes ranged from 37 to 4,461 ( median 242 , interquartile range 199520 ) . overall , 18,547 participants were involved in the present analysis , and among them 15,913 were from the general population , 1,970 were immunocompromised patients , and 664 were ivdus . laboratory methods for all included studies were reported ( 19 detected hhv-8 by elisa , 3 by pcr , and 4 by immunofluorescent assay . the prevalence of hhv-8 pooled from reviewed studies was 11.3% ( 95% ci 7.215.5 ) for the general population , 22.2% ( 95% ci 12.731.8 ) for immunocompromised patients , and 31.2% ( 95% ci 27.734.7 ) for ivdus . the prevalence among the general population was found to be the lowest in guangdong province and the highest in xinjiang province . the prevalence was 34.3% ( 95% ci 28.340.3 ) in zhejiang and 29.6% ( 95% ci 25.333.9 ) in xinjiang uygur autonomous region ( technical appendix table 2 ; figure ) . regional distribution of pooled human herpesvirus 8 ( hhv-8 ) prevalence in a ) the general population and b ) immunocompromised patients , china . five studies , including 4,637 persons of han ethnicity and 4,011 persons of ethnic minorities ( 2,040 uygur , 1,169 kazak , 200 khalkas , 173 hue , and 429 other ) conducted in the xinjiang uygur autonomous region were analyzed for association of ethnicity with hhv-8 prevalence ( technical appendix figure , panel a ) . the risk was significantly lower for the han group than for other ethnic groups ( odds ratio [ or ] = 0.59 , 95% ci 0.550.76 ) . for the han group , the pooled prevalence of hhv-8 in xinjiang uygur autonomous region was significantly higher when compared with that for other regions , 14.4% ( 95% ci 9.019.8 ) versus 6.4% ( 95% ci 4.18.6 ) . ten combined studies , with 5,716 male and 4,708 female participants , respectively , were included in meta - analysis of association between sex and hhv-8 infection ( technical appendix figure , panel b ) . there was no significant difference between the sexes : pooled or 0.94 ( 95% ci 0.841.04 ) . seven studies , with 863 hiv - positive patients and 3,438 negative controls , were included in the analysis . all studies yielded a significant difference in hhv-8 infection between hiv - positive and hiv - negative participants ; ors for individual studies ranged from 1.50 to 4.27 , and the pooled or was 2.97 ( 95% ci 2.223.97 ) ( technical appendix figure , panel c ) . however , a significant publication bias was detected ( egger test p = 0.013 ; begg test p = 0.016 ) . a visual inspection of the funnel plot suggested that some large or small studies with negative or null results were not published ( data not shown ) . few studies were designed to address the issue of possible transmission routes among the population of china . two blood transfusion studies and 4 studies of ivdus included 837 persons who reported having been exposed to blood contact i.e. , needle sharing and 1,397 who were never exposed ( technical appendix figure , panel d ) . substantial heterogeneity ( i 87% , p<0.001 , by test for heterogeneity ) was detected among those studies ; therefore , a random - effects model was used to estimate the or . no publication bias was detected ( begg test p = 0.707 ; egger test p = 0.363 ) . or showed a marginal association of hhv-8 prevalence with blood transfusion ( or 2.01 , 95% ci 0.894.56 ) for possible blood transmission . pooling of data from 26 studies provided us with a large sample size , which is one of the strengths of the study . also , we included studies that were published in the chinese language and were not accessible to the international community . the results of this meta - analysis show that hhv-8 prevalence was higher in the xinjiang uygur autonomous region than other areas in general and among high - risk populations . historically , xinjiang uygur autonomous region has been regarded as an area in which kaposi sarcoma is endemic ( 13 ) . notably , geographic variations of hhv-8 infection within china are not well known and need to be investigated as well . it has been well documented that hhv-8 prevalence is higher among hiv - infected persons ( 14,15 ) . in mainland china , we found a 3-fold increase in hhv-8 infection among persons with hiv compared with hiv - noninfected persons . given the rapid increase of hiv / aids cases in china , hhv-8 could become a severe public health issue in the future . according to data from the xinjiang uygur autonomous region , although there was evidence for considerable heterogeneity among the studies , the association between ethnicity and hhv-8 risk showed that minorities were at higher risk for hhv-8 infection when compared with the han ethnic group . the reasons behind this association are not well elucidated . because all of the comparisons of hhv-8 difference between minority groups and the han ethnic group are from the xinjiang uygur autonomous region , epidemiologic confirmation of this observation would require data from other regions , which is currently unavailable . our analysis showed a marginally significant association between blood contact and hhv-8 infection ; heterogeneity among studies was substantial . these data indicate that blood - borne transmission could occur among the chinese population , a finding that is consistent with previous reports from other countries ( 11 ) . the studies included in this meta - analysis were not evenly distributed throughout china because information was not available from all the regions . also , all of the studies might have used different methods for hhv-8 detection because of the lack of a standard assay ; prevalence estimates may have been underestimated . in summary , this meta - analysis clearly shows that the distribution of hhv-8 seroprevalence varies in china . the available information is still too limited to fully understand hhv-8 prevalence and the risk factors associated with transmission . further studies are urgently needed to explore the epidemiology of hhv-8 infection in different subpopulations in china .
to summarize the seroprevalence of human herpesvirus 8 ( hhv-8 ) in mainland china , we conducted a systematic review and meta - analysis based on available literature . 
 data show that differences in hhv-8 prevalence vary considerably among different ethnic groups and geographic regions . 
 blood - borne transmission could be a potential route for hhv-8 infection in china .