Seroprevalence of transfusion-transmissible infectious agents among volunteer blood donors between 2006 and 2012 in Zhejiang, China

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Abstract

 

Introduction

Despite significant progress made over the last few decades in the prevention of transfusion-transmissible infections (TTI) through blood transfusion, transmission of pathogens such as hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV) and Treponema pallidum (TP) via transfusion still poses a great threat to blood safety. In the global view, the risk of TTI has been drastically reduced by the introduction of routine donor laboratory screening for blood-borne pathogens and by volunteer donations^1,2. As a consequence of continuous implementation and improvement of more sensitive serological methods and nucleic acid amplification tests (NAT), in the European Union and the United States the residual risk of HIV and HCV among all allogeneic donations is currently below 1 per 1 million donations, and that of HBV is close to 1 per 300,000 donations^3,4. In another study, estimates of residual risk among repeat apheresis donors in the United States between 2007 and 2008 were 1:1.0 million for HIV, 1:3.2 million for HCV, and 1:200,000 for HBV⁵. Furthermore, one recent study in the United States showed that with the addition of minipool-NAT, and resulting 8.8-day window-period reduction, residual risks for HBV decreased from 1:765,000 to 1:1,006,000⁶. In China and other developing countries, the risks of TTI are higher than those in above-mentioned developed nations^7–10.

With the rapid growth of the Chinese economy in the last 30 years, the blood transfusion services in China have experienced great transformation and development. By the end of 2012, there were 531 Blood Centres/Banks in China, organised in three levels: provincial, regional and county Blood Services (according to the Chinese Health Statistical Digest, 2013–2014 issued by the National Health and Family Planning Commission of People’s Republic of China: http://www.nhfpc.gov.cn/ewebeditor/uploadfile/2014/04/20140430131845405.pdf, last accessed on 01/09/2014). Since the Blood Donation Law came into effect in 1998, many changes have been made in the field of blood banking in China and blood collection has been successfully transformed from paid and family member donations to voluntary donations. Compared to 1998, when paid donations or donations from family members made up 80% of its blood supplies, China has achieved 98.5% voluntary donations in just 10 years (http://www.who.int/mediacentre/news/releases/2008/pr18/en/, last accessed on 01/09/2014). Currently, the blood donation rate is only 9‰ of the whole population in China, which is much lower than the desired rate indicated by the World Health Organisation (WHO): 10–30‰.

Although the volume of blood collected has increased dramatically, the increase in the blood supply has not kept pace with the increasing clinical demand for blood in China. Furthermore, besides the problem of blood availability, there are great challenges in ensuring blood safety. The high prevalences of HBV and HCV, paralleling the growing epidemics of HIV and TP in the general Chinese population, are at the basis of these challenges. While there has been some research focusing on the prevalence of these infectious diseases in the general Chinese population, epidemiological data on the seroprevalence of TTI agents among Chinese volunteer blood donors are still limited despite recent publications by Wang et al^9,10. In this study, we investigated the seroprevalence of transfusion-transmissible pathogenic agents including HBV, HCV, HIV and TP among blood donors from 2006 to 2012 in Zhejiang Province, which is one of the most prosperous areas in China.

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Materials and methods

Participants and study procedure

Zhejiang Province is located in the southern part of the Yangtze River Delta on the southeast coast of China with the East China Sea lying to the east. The resident population of the province was 54.77 million at the end of 2012. We selected five cities/regions as representative of the province: Hangzhou, Xiaoshan, Jiande, Wenzhou and Lishui. Each of these cities or regions has only one Blood Service, except Wenzhou, which has one blood station and four Blood Banks. The data for Wenzhou come from all the Blood Services in the region. Hangzhou city, the capital of Zhejiang Province, is the province’s economic, cultural, scientific and educational centre. Xiaoshan and Jiande are two districts of Hangzhou. They have their own Blood Banks, but the blood testing was done in Hanzhou. Wenzhou is a prefecture-level region in the south-east of Zhejiang Province, and Lishui is a prefecture-level region in the south-west of Zhejiang Province. The regions of Jiande and Lishui are less economically developed than Hangzhou, Xiaoshan and Wenzhou, and there are more farmers and fewer migrant people living in these two regions.

Our study population consisted of all whole blood and apheresis donors in the five cities/regions from January 2006 through December 2012. All the candidate donors underwent pre-donation screening. The whole process included a health history questionnaire, a brief physical examination and rapid predonation testing. If donors reported in questionnaire that they had been diagnosed as having HIV infection, syphilis, or any other sexually transmitted disease or viral hepatitis, they were permanently deferred. Next, the donors had to pass a physical examination regarding body weight and blood pressure. Rapid pre-donation testing included haemoglobin level, hepatitis B virus surface antigen (HBsAg), alanine aminotransferase level and determination of ABO blood group. Potential donors with a low haemoglobin level (lower than 120 g/L in males; in females, lower than 110 g/L before June 2012 and lower than 115 g/L since June 2012), abnormal alanine aminotransferase or positive HBsAg results were temporarily deferred. All successful donations then underwent two rounds of routine serological testing for HBsAg, anti-HCV, anti-HIV1/2 and anti-TP by two different reagents according to the manufacturers’ instructions; both imported and domestic testing kits, approved and licensed by the Chinese State Food and Drug Administration, were used (listed in Table I). We used a dual screening strategy to test donations. If the test results from either assay in the strategy were reactive, the sample was judged positive, the donation was discarded and the donor was permanently deferred. We extracted all data for the years 2006 to 2012 from the unified electronic database and analysed them.

Table I

HBsAg, anti-HCV, anti-HIV1/2 and anti-TP reagents used for screening donors.

Kit name	Company
Diagnostic kit for HBV surface antigen (ELISA)	InTec Products, Inc. (Xiamen, China); Ke-Hua BIO-Engineering Co., Ltd. (Shanghai, China); BioMérieux Clinical Diagnostics (Shanghai, China); Murex Biotech Limited (Dartford, UK)
Diagnostic kit for antibody to HCV (ELISA)	InTec Products, Inc. (Xiamen, China); Ke-Hua BIO-Engineering Co., Ltd. (Shanghai, China); Ortho-Clinical Diagnostics, Inc. (New Jersey, USA)
Diagnostic kit for antibody to HIV-1/2 (sandwich ELISA)	Livzon Diagnostics Inc. (Zhuhai, China); BioMérieux Clinical Diagnostics (Shanghai, China); Bio-Rad (Marnes-la-Coquette, France)
Diagnostic kit for antibody to Treponema pallidum (ELISA)	InTec Products, Inc. (Xiamen, China); Wan-Tai Biological Pharmacy Enterprise Co., Ltd. (Beijing, China)

HBsAg: hepatitis B virus surface antigen; HCV: hepatitis C virus; HIV: human immunodeficiency virus; TP: Treponema pallidum; HBV: hepatitis B virus.

Statistical analysis

Statistical analyses were conducted using SPSS 13.0 statistics software. The chi-square test was applied to assess associations between categorical variants. The chi-square test for trends was used to analyse the differences in seroprevalence of TTI markers among different demographic groups. A p-value <0.05 was considered statistically significant.

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Results

Demographic characteristics of the blood donors

Overall 1,615,120 whole blood and apheresis donations were collected at the Blood Services in the five cities/regions between January 1, 2006 and December 31, 2012. The demographic characteristics associated with all donations are shown in Table II. Almost 60% of the donations came from male donors. Although, overall, almost half of the donors were 25 years of age or younger, there was a clear difference between the ages of the donors from the five cities/regions. In Jiande and Lishui, the proportions of donors who were 25 years or younger were much lower than the proportions in the other three cities/regions. Information on education and marital status was missing for more than 10% of donors. The proportion of donors with an associate degree or higher level of education was highest in Hangzhou and lowest in Jiande. Information on marital status was most complete for the donors in Jiande and Lishui from among all the five cities/regions. As to the ethnic structure of the donors, about 1% of all the donations were collected from people in ethnic minorities. Overall, approximately 40% of donations came from first-time donors and 60% from repeat donors. In Lishui, more than 70% of donors were repeat donors.

Table II

Demographic characteristics associated with all donations in five different cities/regions from 2006 to 2012.

Donor characteristics	Hangzhou	Xiaoshan	Jiande	Wenzhou	Lishui	Overall
Total number of donations	924,319	101,619	82,355	321,463	185,364	1,615,120
Sex
Male	550,960 (59.61)	65,731 (64.68)	45,973 (55.82)	207,304 (64.49)	110,027 (59.36)	979,995 (60.68)
Female	373,359 (40.39)	35,888 (35.32)	36,382 (44.18)	114,148 (35.51)	75,297 (40.62)	635,125 (39.32)
Age (years)
18–25	494,578 (53.51)	40,943 (40.29)	20,136 (24.45)	139,984 (43.55)	53,914 (29.09)	749,555 (46.41)
26–35	265,542 (28.73)	32,539 (32.02)	20,214 (24.54)	10,8430 (33.73)	50,625 (27.31)	477,350 (29.56)
36–45	134,796 (14.58)	21,100 (20.76)	26,644 (32.35)	57,498 (17.89)	54,765 (29.54)	294,803 (18.25)
46–55	29,403 (3.18)	7,037 (6.92)	15,361 (18.65)	15,551 (4.84)	26,060 (14.06)	93,412 (5.78)
Education
Middle school or less	152,465 (16.49)	28,008 (27.56)	26,318 (31.96)	95,389 (29.67)	73,326 (39.56)	375,506 (23.25)
High school graduate	156,338 (16.91)	21,726 (21.38)	33,160 (40.26)	67,720 (21.07)	38,883 (20.98)	317,827 (19.68)
Associate degree	229,732 (24.85)	30,717 (30.23)	15,561 (18.90)	68,697 (21.37)	48,256 (26.03)	392,963 (24.33)
Complete university and above	218,874 (23.68)	11,044 (10.87)	7,146 (8.68)	49,155 (15.29)	23,385 (12.62)	309,604 (19.17)
Missing	166,910 (18.06)	10,124 (9.96)	170 (0.20)	40,502 (12.60)	1,514 (0.82)	219,220 (13.57)
Ethnicity
Han	914,400 (98.93)	99,557 (97.97)	81,853 (99.39)	311,463 (96.89)	182,168 (98.28)	1,589,441 (98.41)
Minority	9,733 (1.05)	2,056 (2.02)	502 (0.61)	9,913 (3.08)	3,195 (1.72)	25,399 (1.57)
Missing	186 (0.02)	6 (0.01)	0 (0.00)	87 (0.03)	1 (0.00)	280 (0.02)
Marital status
Single	460,857 (49.86)	50,614 (49.81)	61,384 (74.54)	113,558 (35.33)	120,947 (65.25)	807,360 (49.99)
Married	228,449 (24.72)	41,115 (40.46)	20,580 (24.99)	146,418 (45.55)	63,501 (34.26)	500,063 (30.96)
Missing	235,013 (25.43)	9,890 (9.73)	391 (0.47)	61,487 (19.13)	916 (0.49)	307,697 (19.05)
Donor status
First time	399,825 (43.26)	43,793 (43.10)	32,769 (39.79)	140,962 (43.85)	49,648 (26.78)	666,997 (41.30)
Repeat	524,494 (56.74)	57,826 (56.90)	49,586 (60.21)	180,501 (56.15)	135,716 (73.22)	948,123 (58.70)

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Data are shown as number (%).

Overall seroprevalence and trend of infectious markers over time

The serological status of the 1,615,120 donations examined with dual enzyme-linked immunosorbent assays (ELISA) for HBsAg, anti-HCV, anti-HIV1/2 and anti-TP from 2006 to 2012 is presented in Table III. The overall seroprevalence rates of HBV, HCV, HIV and TP were 0.51%, 0.25%, 0.15% and 0.52%, respectively. We determined the seroprevalence rates of the four pathogens year by year. The overall prevalence of HCV and HIV remained relatively steady, while the prevalence of TP rose sharply from 2010, and the prevalence of HBV became higher in 2011 and 2012 (Figure 1).

 

Figure 1

Prevalence of serologic markers for TTIs by dual ELISA-reactive status at Blood Services in five cities/regions between 2006 to 2012.

TTI: transfusion-transmissible infection.

Table III

Prevalence of serological markers for TTI by dual ELISA-reactive status at Blood Services in five cities/regions between 2006 and 2012.

Blood Centre	2006	2007	2008	2009	2010	2011	2012	Overall
HBsAg
Hangzhou	0.55	0.43	0.46	0.51	0.48	0.52	0.65	0.52*
Xiaoshan	0.29	0.37	0.48	0.33	0.52	0.40	0.48	0.49
Jiande	0.41	0.40	0.66	0.82	0.67	0.61	0.78	0.65*
Wenzhou	0.25	0.30	0.31	0.41	0.48	0.50	0.54	0.40*
Lishui	0.36	0.63	0.42	0.55	0.67	0.81	0.71	0.60*
Overall	0.44	0.42	0.44	0.50	0.51	0.58	0.66	0.51
Anti-HCV
Hangzhou	0.25	0.30	0.22	0.25	0.32	0.32	0.31	0.26*
Xiaoshan	0.08	0.18	0.24	0.23	0.25	0.28	0.41	0.25
Jiande	0.13	0.17	0.21	0.21	0.24	0.39	0.51	0.27
Wenzhou	0.18	0.20	0.22	0.22	0.30	0.31	0.40	0.27
Lishui	0.06	0.10	0.11	0.14	0.21	0.22	0.38	0.18*
Overall	0.20	0.24	0.21	0.23	0.30	0.29	0.30	0.25
Anti-HIV
Hangzhou	0.16	0.09	0.13	0.16	0.16	0.12	0.11	0.13*
Xiaoshan	0.04	0.08	0.10	0.13	0.13	0.11	0.14	0.12
Jiande	0.08	0.08	0.11	0.12	0.15	0.09	0.14	0.13
Wenzhou	0.10	0.16	0.17	0.16	0.18	0.24	0.33	0.19*
Lishui	0.04	0.12	0.12	0.12	0.15	0.18	0.28	0.15
Overall	0.12	0.11	0.13	0.15	0.16	0.15	0.20	0.15
Anti-TP
Hangzhou	0.38	0.38	0.41	0.39	0.43	0.60	0.68	0.44*
Xiaoshan	0.24	0.39	0.43	0.50	0.50	0.59	0.63	0.48
Jiande	0.92	0.89	0.93	1.06	1.02	1.02	0.97	0.98*
Wenzhou	0.34	0.52	0.54	0.57	0.56	0.59	0.66	0.55*
Lishui	0.39	0.62	0.71	0.68	0.77	0.85	0.72	0.69*
Overall	0.39	0.46	0.50	0.49	0.53	0.62	0.62	0.52

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Data are reported as percentages;

^*p<0.05, the prevalence of serological markers in different regions was compared with the overall prevalence among blood donors.

TTI: transfusion-transmissible infections; HBsAg: hepatitis B virus surface antigen; HCV: hepatitis C virus; HIV: human immunodeficiency virus; TP: Treponema pallidum; HBV: hepatitis B virus.

The seroprevalence of HBsAg was estimated to be 0.52%, 0.49%, 0.65%, 0.40% and 0.60% in Hangzhou, Xiaoshan, Jiande, Wenzhou and Lishui, respectively. The prevalence in each city/region differed significantly from the overall mean seroprevalence except for Xiaoshan (Table III, p<0.05). The rate of HBsAg positivity was higher in Lishui and Jiande than in the other Blood Services (p<0.05). In all five cities/regions, except Xiaoshan, the trend in HBsAg prevalence was the same, i.e. an increase in the last 2 years studied, 2011 and 2012.

The prevalence of HCV in Lishui was significantly lower than the overall mean prevalence of HCV (p<0.05). While the prevalence of HCV remained relatively steady in Hangzhou over the years, the prevalence in the other four cities/regions showed an upward annual trend.

The trend in HIV prevalence was similar. While the prevalence in Hangzhou remained relatively steady over the years, the prevalence of HIV in the other four cities/regions showed an upward annual trend. The prevalence of HIV in Wenzhou was significantly higher than the overall mean prevalence (p<0.05).

The prevalence of anti-TP positivity in all five cities/regions rose steadily. Among the five cities/regions, the rate of anti-TP positivity was highest in Jiande, followed by Lishui and Wenzhou; the rate was lowest in Hangzhou.

Seroprevalence of infectious markers among different demographic groups

We also studied the seroprevalence of markers of TTI among different demographic groups (Table IVa and IVb). The prevalence of HBV tended to be higher among male donors than female donors through the 7 years we studied (p<0.05), but the prevalence of markers of syphilis was higher among female donors than among male donors (p<0.05). As regards HCV and HIV, female donors had a lower prevalence than male donors from 2006 to 2009, but with the prevalence of these infections increasing at a rate faster in women than in men, the prevalence among female donors was higher than that among male donors from 2010 to 2012.

Table IVa

Prevalence of serological markers for TTI by dual ELISA-reactive status among different demographic groups in 2006–2012.

Donors’ characteristics	2006				2007				2008				2009
	HBsAg	Anti-HCV	Anti-HIV	Anti-TP	HBsAg	Anti-HCV	Anti-HIV	Anti-TP	HBsAg	Anti-HCV	Anti-HIV	Anti-TP	HBsAg	Anti-HCV	Anti-HIV	Anti-TP
Sex
Male	0.45	0.21	0.13	0.38	0.43	0.25	0.11	0.45	0.46	0.21	0.13	0.49	0.52	0.26	0.18	0.49
Female	0.43	0.20	0.12	0.40	0.41	0.22	0.11	0.49	0.40	0.22	0.12	0.52	0.49	0.20	0.13	0.53
Age (years)
18–25	0.38	0.23	0.14	0.26	0.37	0.25	0.12	0.31	0.34	0.24	0.15	0.32	0.34	0.30	0.20	0.30
26–35	0.49	0.24	0.15	0.32	0.45	0.22	0.10	0.68	0.56	0.21	0.12	0.65	0.55	0.23	0.14	0.64
36–45	0.48	0.14	0.12	0.41	0.47	0.16	0.10	0.78	0.62	0.16	0.13	0.73	0.66	0.16	0.13	0.76
46–55	0.53	0.19	0.10	0.50	0.52	0.14	0.10	0.58	0.60	0.10	0.10	0.80	0.68	0.16	0.06	0.85
Education
Middle school or less	0.54	0.31	0.14	0.44	0.52	0.27	0.14	0.76	0.54	0.24	0.13	0.84	0.63	0.24	0.22	0.85
High school graduate	0.50	0.20	0.13	0.35	0.35	0.23	0.16	0.54	0.42	0.21	0.12	0.56	0.43	0.24	0.15	0.46
Associate degree	0.39	0.15	0.13	0.30	0.37	0.20	0.11	0.23	0.31	0.21	0.11	0.21	0.34	0.26	0.08	0.21
Complete university and above	0.32	0.14	0.07	0.16	0.28	0.23	0.09	0.21	0.26	0.17	0.09	0.16	0.23	0.21	0.09	0.19
Ethnicity
Han	0.45	0.20	0.12	0.38	0.42	0.24	0.12	0.49	0.44	0.21	0.13	0.50	0.50	0.23	0.15	0.49
Minority	0.41	0.21	0.11	0.48	0.49	0.29	0.10	0.58	0.50	0.20	0.10	0.45	0.47	0.27	0.19	0.50
Marital status
Single	0.42	0.31	0.16	0.32	0.48	0.46	0.13	0.31	0.39	0.25	0.14	0.34	0.38	0.30	0.22	0.33
Married	0.60	0.28	0.14	0.81	0.55	0.53	0.12	0.67	0.68	0.24	0.12	0.69	0.42	0.23	0.18	0.65
Donor status
First time	0.53	0.34	0.15	0.76	0.78	0.37	0.17	0.96	0.71	0.37	0.21	1.00	0.86	0.40	0.21	1.00
Repeated	0.13	0.05	0.03	0.10	0.13	0.06	0.05	0.09	0.19	0.07	0.03	0.12	0.16	0.07	0.04	0.13

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Data are reported as percentages. TTI: transfusion-transmissible infections; HBsAg: hepatitis B virus surface antigen; HCV: hepatitis C virus; HIV: human immunodeficiency virus; TP: Treponema pallidum.

Table IVb

Prevalence of serological markers for TTI by dual ELISA-reactive status among different demographic groups in 2006–2012.

Donors’ characteristics	2010				2011				2012
	HBsAg	Anti-HCV	Anti-HIV	Anti-TP	HBsAg	Anti-HCV	Anti-HIV	Anti-TP	HBsAg	Anti-HCV	Anti-HIV	Anti-TP
Sex
Male	0.54	0.27	0.14	0.48	0.61	0.28	0.13	0.61	0.70	0.28	0.17	0.58
Female	0.43	0.34	0.18	0.51	0.55	0.31	0.17	0.65	0.60	0.30	0.22	0.66
Age (years)
18–25	0.32	0.33	0.16	0.29	0.32	0.50	0.14	0.31	0.31	0.33	0.25	0.32
26–35	0.49	0.24	0.12	0.62	0.55	0.52	0.14	0.60	0.61	0.22	0.15	0.69
36–45	0.68	0.24	0.12	0.88	0.57	0.53	0.16	0.78	0.97	0.30	0.13	0.80
46–55	0.83	0.29	0.15	0.93	0.80	0.41	0.16	0.88	0.65	0.20	0.17	0.90
Education
Middle school or less	0.67	0.35	0.18	0.84	0.71	0.31	0.14	0.76	0.72	0.34	0.18	0.78
High school graduate	0.56	0.32	0.14	0.55	0.55	0.23	0.16	0.54	0.57	0.21	0.21	0.67
Associate degree	0.39	0.25	0.13	0.30	0.42	0.22	0.11	0.33	0.40	0.21	0.15	0.33
Complete university and above	0.22	0.24	0.12	0.16	0.20	0.25	0.13	0.21	0.26	0.17	0.14	0.16
Ethnicity
Han	0.51	0.30	0.16	0.53	0.58	0.29	0.15	0.62	0.66	0.30	0.20	0.62
Minority	0.41	0.20	0.11	0.58	0.60	0.29	0.10	0.58	0.70	0.20	0.20	0.60
Marital status
Single	0.42	0.31	0.16	0.52	0.48	0.30	0.13	0.51	0.49	0.35	0.22	0.54
Married	0.60	0.28	0.14	0.56	0.55	0.27	0.12	0.67	0.68	0.24	0.18	0.69
Donor status
First time	0.95	0.44	0.22	1.09	0.98	0.39	0.24	1.16	1.01	0.43	0.27	1.23
Repeated	0.15	0.08	0.06	0.12	0.19	0.12	0.07	0.17	0.25	0.12	0.11	0.14

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Data are reported as percentages. TTI: transfusion-transmissible infections; HBsAg: hepatitis B virus surface antigen; HCV: hepatitis C virus; HIV: human immunodeficiency virus; TP: Treponema pallidum.

In donors younger than 25 years old, there was upward tendency in HCV and HIV prevalence, but the prevalence of syphilis among this age group remained relatively stable and lower than that in other age groups (p<0.05). The prevalence of syphilis was higher in older age groups. As regards HBV, the prevalence in 18- to 25-year olds showed a declining trend.

Through the 7 years, it was evident that the donor groups with more education had the lower prevalences of HBV and syphilis. For HCV and HIV, the difference between donor groups with high education and low education was not so clear, although generally, donors with a good education tended to be less likely to be infected.

Because of the small number of minority donors, the prevalence of infectious agents among ethnic minority donors fluctuated more wildly than among Han donors. Syphilis and HBV were more prevalent among married donors than among single donors (p<0.05), but the prevalence of HCV and HIV was higher among single donors than among married donors most of the time.

The prevalence of markers of TTI was much higher among first-time donors than among repeat donors (p<0.05) and showed an upward trend among first-time donors. While the prevalence of syphilis and HBV among repeat donors stayed stable, the prevalence of HCV and HIV among repeat donors showed a slow, upward trend (Figure 2).

 

 

Figure 2

Prevalence of serologic markers for TTIs among first time donors and repeated donors between 2006 to 2012.

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Discussion

China is facing critical challenges both in the availability and safety of blood for transfusions. With the rapid urbanisation and improvement of health care, ever more surgical procedures are being performed in hospitals. As a result, the clinical demand for blood transfusion is increasing at a rate that the blood supply cannot keep pace with, so China faces consistent seasonal and/or regional blood shortages. Furthermore, blood safety is still a serious problem in China. Due to the strong commitment of the government and extensive national and local campaigns, a huge change has occurred in the way Chinese people think about blood donation. In contrast to 1998, when paid donations or donations from family members made up 80% of its blood supplies, China has achieved almost 100% voluntary donations. Despite such a successful change, the emerging HIV epidemic, the growing TP epidemic and the high prevalence HBV and HCV in the general population risk compromising blood safety in China.

To ensure blood safety, it is critical to monitor ongoing epidemiological information, not only from high-risk groups, but also from individuals in the general population such as volunteer blood donors. The demographic characteristics of the donors from the five cities/regions that we studied are quite different from the profile of donors from some Western countries. According to a survey of English blood donors in January, 2005, almost three-quarters of donors were above 30 years old, and there were more female donors than male donors¹¹. The other study carried out in England and North Wales during 2010 and 2011 found that the number of repeat blood donors was five times higher than the number of first-time blood donors¹². Our findings were different: 60% of donors were male, more than 45% of blood donors were under the age of 25, and more than 40% of donations were from first-time donors. To ensure an adequate blood supply, it is critical to recruit suitable blood donors. In China, the recruiting strategies to encourage the current 40% of first-time donors to return for regular donation are very important to compensate for the blood shortage.

Since the first case of HIV infection in 1985, the number of HIV positive cases has continued to grow in Zhejiang Province, China. According to an interview with an official from the Health Bureau of Zhejiang Province, by November 25, 2012 (http://www.gov.cn/gzdt/2012-12/01/content_2280006.htm, last accessed on 01/09/2014) there were 11,416 reported cases of HIV infection, including 4,277 cases of AIDS and 1,348 recorded deaths. During the period from January 1 to November 25, 2012, there were 2,513 newly reported cases of HIV. This was a 20.4% increase compared to the same period in 2011. In our study, the prevalence of HIV also increased among blood donors, both first-time and repeat donors, in recent years. The rising tendency in young donors (less than 35 years old) and well-educated donors (complete university education and beyond) suggests that HIV transmission may pose a big threat to the active labour force in the province.

HBV is highly endemic in China. Of the 350 million to 400 million individuals infected worldwide with the HBV, one-third live in China, with 130 million carriers and 30 million chronically infected subjects^13,14. Since the nationwide HBV vaccination programme was implemented in 1992, the prevalence of HBsAg in the Chinese population has dropped to 7.2%. Due to rapid, pre-donation HBsAg testing and donor inquiry, the prevalence of HBsAg (0.51%) was much lower in the donor population in our study than that in the general population^7,8. According to a survey in Hangzhou between August 1, 2010 and December 31, 2011, 180,674 candidate blood donors were pre-screened for HBsAg status by a rapid HBsAg assay. Among them, 2,197 (1.22%) were found to be positive and were, therefore, deferred from donation. This suggests that the real prevalence of HBV among the potential donors in this region was much higher than indicated by our data. However, as our study focuses on prevalence trends in donors who donated blood, such an underestimate may not have influenced our conclusions substantially. The seroprevalence of HBV was significantly higher among older, male, less educated, married and first-time donors, as compared to younger, female, more educated, unmarried or repeat donors, respectively.

HCV and HIV infection were frequently detected among paid blood donors in China during the early 1990s^15–18. When the Blood Donation Law came into effect in 1998, the use of paid blood donors was outlawed. As a result, volunteer donors now constitute the majority of blood donors in China. This transformation in the composition of blood donors in China has been associated with a gradual decrease in the seroprevalence of anti-HCV among donors¹⁷. The HCV seroprevalence among the general population of China has been estimated to be about 3.2%, while among paid blood donors, the prevalence was 5.7% or higher^19–21. Similar to the situation of HBV, the seroprevalence of HCV among volunteer blood donors in our study (0.25%) was lower than that among the general population. This may be attributed to the inquiry and physical examination of donors before donation and the fact that over half of the donations were from repeat donors. Unlike the situation with HBV, it was the younger donors who tended to have a higher prevalence of HCV and first-time donation was also associated with greater likelihood of HCV infection.

China has experienced a dramatic resurgence of syphilis in recent years. In one recent study in China, the incidence of TP infection increased yearly from 6.43 per 100,000 person-years in 2000 to 32.86 per 100,000 person-years in 2013, with an average annual growth rate of 13.37%²². The study also indicated a significant difference in the incidence of TP infection between different regions, with Zhejiang Province being among those regions with a high incidence. One study at five Chinese Blood Centres demonstrated the increasing prevalence of serological markers for syphilis also among Chinese blood donors²³. Our study showed that the prevalence of TP infection rose steadily among first-time blood donors in recent years, while the prevalence among repeat donors remained stable. The risk factors for TP infection were older age, being female, being less educated and being a first-time donor.

In this study, we collected data on the seroprevalence of TTI agents among volunteer blood donors in Zhejiang, China. Some limitations of the study should be acknowledged. First, we did not perform further confirmatory tests on the reactive donations, so the real prevalence of TTI among donors was not evaluated precisely. Second, not all Blood Services used the same kits during the study period, and the assay reagents varied: Hangzhou, Xiaoshan and Jiande used the same kits, while Wenzhou and Lishui Blood Services used different ones, thus also weakening the conclusions about the regional differences in prevalence.

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Conclusion

We collected data on the seroprevalence of TTI agents, including HBV, HCV, HIV and TP, among volunteer blood donors in Zhejiang, China. As a result of conversion to volunteer blood donation, pre-donation inquiry, rapid testing and screening for seromarkers of TTI, the risk of infections transmitted by transfusion has been greatly reduced in China. More sensitive screening methods, such as nucleic acid amplification testing, and recruitment of regular donors are still very important for improving blood safety and availability.

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Acknowledgements

This work was supported by the Science Research Foundation of Zhejiang Province (2013C03047-2) and Zhejiang Provincial Programme for the Cultivation of High-Level Innovative Health Talents.

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Footnotes

Authorship contributions

XZ performed the research, analysed data and wrote the paper. WD, GL, YW, DW, BW, and LZ performed the research. HZ and JH performed the research and analysed data. FZ designed the research study and wrote the paper. HL designed the research study and analysed the data.

The Authors declare no conflicts of interest.

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References

1. Allain JP, Thomas I, Sauleda S. Nucleic acid testing for emerging viral infections. Transfus Med. 2002;12:275–83. [PubMed] [Google Scholar]
2. Luban NL. Transfusion safety: Where are we today? Ann NY Acad Sci. 2005;1054:325–41. [PubMed] [Google Scholar]
3. Velati C, Romano L, Fomiatti L, et al. Impact of nucleic acid testing for hepatitis B virus, hepatitis C virus, and human immunodeficiency virus on the safety of blood supply in Italy: a 6-year survey. Transfusion. 2008;48:2205–13. [PubMed] [Google Scholar]
4. Zou S, Stramer SL, Dodd RY. Donor testing and risk: current prevalence, incidence, and residual risk of transfusion-transmissible agents in US allogeneic donations. Transfus Med Rev. 2012;26:119–28. [PubMed] [Google Scholar]
5. Zou S, Musavi F, Notari EP, et al. Prevalence, incidence, and residual risk of major blood-borne infections among apheresis collections to the American Red Cross Blood Services, 2004 through 2008. Transfusion. 2010;50:1487–94. [PubMed] [Google Scholar]
6. Stramer SL, Notari EP, Krysztof DE, Dodd RY. Hepatitis B virus testing by minipool nucleic acid testing: does it improve blood safety? Transfusion. 2013;53:2449–58. [PubMed] [Google Scholar]
7. Al Shaer L, AbdulRahman M, John TJ, AlHashimi A. Trends in prevalence, incidence, and residual risk of major transfusion-transmissible viral infections in United Arab Emirates blood donors: impact of individual-donation nucleic acid testing, 2004 through 2009. Transfusion. 2012;52:2300–9. [PubMed] [Google Scholar]
8. Moiz B, Moatter T, Shaikh U, et al. Estimating window period blood donations for human immunodeficiency virus Type 1, hepatitis C virus, and hepatitis B virus by nucleic acid amplification testing in Southern Pakistan. Transfusion. 2014;54:1652–9. [PubMed] [Google Scholar]
9. Wang J, Liu J, Yao F, et al. Prevalence, incidence, and residual risks for transfusion-transmitted human immunodeficiency virus types 1 and 2 infection among Chinese blood donors. Transfusion. 2013;53:1240–9. [PMC free article] [PubMed] [Google Scholar]
10. Wang J, Liu J, Huang Y, et al. The persistence of hepatitis C virus transmission risk in China despite serologic screening of blood donations. Transfusion. 2013;53:2489–97. [PubMed] [Google Scholar]
11. Contreras M, editor. ABC of Transfusion. 4th edition. Oxford: Wiley-Blackwell Publishing; 2009. pp. 1–5. [Google Scholar]
12. Lattimore S, Wickenden C, Brailsford SR. Blood donors in England and North Wales: demography and patterns of donation. Transfusion. 2015;55:91–9. [PubMed] [Google Scholar]
13. Custer B, Sullivan SD, Hazlet TK, et al. Global epidemiology of hepatitis B virus. J Clin Gastroenterol. 2004;38(Suppl 3):S158–68. [PubMed] [Google Scholar]
14. Liu J, Fan D. Hepatitis B in China. Lancet. 2007;369:1582–3. [PubMed] [Google Scholar]
15. Beach MV. “Blood heads” and AIDS haunt China’s countryside. Lancet. 2001;357:49. [PubMed] [Google Scholar]
16. Kaufman J, Jing J. AIDS: China and AIDS - the time to act is now. Science. 2002;296:2339–40. [PubMed] [Google Scholar]
17. Shan H, Wang JX, Ren FR, et al. Blood banking in China. Lancet. 2002;360:1770–5. [PubMed] [Google Scholar]
18. Wu Z, Liu Z, Detels R. HIV-1 infection in commercial plasma donors in China. Lancet. 1995;346:61–2. [PubMed] [Google Scholar]
19. Xia GL, Liu CB, Cao HL, et al. Prevalence of hepatitis B and C virus infections in the general Chinese population: results from a nationwide cross-sectional seroepidemiologic study of hepatitis A, B, C, D, and E virus infections in China, 1992. Int Hepatol Commun. 1996;5:62–73. [Google Scholar]
20. Lei XZ, Shigeko N, Deng XW, et al. Prevalence of hepatitis C virus infection in the general population and patients with liver disease in China. Hepatol Res. 1999;14:135–43. [Google Scholar]
21. Wang Y, Tao QM, Zhao HY, et al. Hepatitis C virus RNA and antibodies among blood donors in Beijing. J Hepatol. 1994;21:634–40. [PubMed] [Google Scholar]
22. Gong XD, Yue XL, Teng F, et al. Syphilis in China from 2000 to 2013: epidemiological trends and characteristics. Chin J Dermatol. 2014;47:310–5. [Google Scholar]
23. Liu J, Huang Y, Wang J, et al. The increasing prevalence of serologic markers for syphilis among Chinese blood donors in 2008 through 2010 during a syphilis epidemic. Transfusion. 2012;52:1741–9. [PubMed] [Google Scholar]

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