Vital Surveillances: Epidemiological and Population Characteristics of Seroprevalence of TTIs Among Voluntary Blood Donors — Guangzhou City, Guangdong Province, China, 2014–2023

This study retrospectively analyzed data from voluntary blood donations at the Guangzhou Blood Center between January 2014 and December 2023. Potential donors underwent a standardized pre-donation screening process that included a health history questionnaire, rapid testing, and a brief physical examination, as mandated by the National Health Commission of China. Donors were required to meet specific eligibility criteria, which excluded those with risk behaviors, abnormal test results, or failed physical examinations. Medical and sociodemographic information of eligible donors was recorded, and blood samples were collected in EDTA-K2 anticoagulant tubes. Donors with no prior donation records at our center were classified as first-time donors, while those with existing donation records were categorized as repeat donors.

All donor samples were tested for TTIs, including hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV), anti-human immunodeficiency virus (anti-HIV), and anti-Treponema pallidum (anti-TP), using two different enzyme-linked immunosorbent assay (EIA) kits from different manufacturers. All test reagents were approved by the China National Medical Products Administration. The specific manufacturers of the EIA kits are listed in Supplementary Table S1 . Donor blood samples that were reactive in both EIA tests were defined as TTI-positive. HIV antibody-reactive results were confirmed by the AIDS reference laboratory.

To calculate the seroprevalence of TTIs, the number of donors who tested positive was divided by the overall number of donations, with the resulting value expressed as per 100,000 donations. Statistical analyses were conducted using SPSS software (version 25.0; IBM Corp., Armonk, NY, USA). Associations between categorical variables were assessed using the Chi-square test. Statistical significance was set at P<0.05.

Between 2014 and 2023, 3,111,265 blood donor samples were collected in Guangzhou. Among these, 26,954 donors (866.34 per 100,000) tested seropositive for at least one TTI. The highest seroprevalence rate was observed for HBsAg, followed by anti-TP. The seroprevalence rates for HBsAg, anti-HCV, anti-HIV, anti-TP, and co-infections were 592.46 per 100,000, 67.01 per 100,000, 19.00 per 100,000, 202.62 per 100,000, and 14.62 per 100,000, respectively.

To investigate temporal trends, we conducted a year-by-year analysis of seroprevalence rates for each pathogen. Over the past decade, the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP among blood donors in Guangzhou demonstrated a consistent downward trend. The HBsAg seroprevalence rate decreased from 842.26 per 100,000 in 2014 to 381.37 per 100,000 in 2023. Similarly, the anti-HCV seroprevalence rate declined from 147.44 per 100,000 in 2014 to 28.33 per 100,000 in 2023. The anti-HIV seroprevalence rate also decreased, falling from 26.1 per 100,000 in 2014 to 9.75 per 100,000 in 2023. Moreover, the anti-TP seroprevalence rate decreased from 353.51 per 100,000 in 2014 to 121.84 per 100,000 in 2023 (Figure 1, Supplementary Table S2).

Figure 1. 

Seroprevalence rate of (A) HBsAg, (B) HCV, (C) HIV, and (D) TP among blood donors in Guangzhou from 2014 to 2023.

Abbreviation: HBsAg=Hepatitis B virus surface antigen; HCV=Hepatitis C virus; HIV=Human immunodeficiency virus; TP=Treponema pallidum; TTIs=Transfusion-transmitted infections.

Overall, the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP were significantly higher in male donors compared to female donors (Supplementary Table S3). From 2014 to 2023, the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP in male donors exhibited a marked downward trend, and the rates for HBsAg, anti-HCV, and anti-TP in female donors also decreased. In contrast, the seroprevalence rate of anti-HIV showed only a slight decrease over the decade in female donors. The disparity in seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP between male and female donors has progressively narrowed. However, as of 2023, male donors still exhibited significantly higher seroprevalence rates for both HBsAg and anti-HIV compared to female donors (Figure 2).

Figure 2. 

Seroprevalence rates of (A) HBsAg, (B) HCV, (C) HIV, and (D) TP among blood donors of different genders in Guangzhou from 2014 to 2023.

Abbreviation: HBsAg=Hepatitis B virus surface antigen; HCV=Hepatitis C virus; HIV=Human immunodeficiency virus; TP=Treponema pallidum; TTIs=Transfusion-transmitted infections.

Compared to the 18–24 age group, the seroprevalence rates of HBsAg, anti-HCV, and anti-TP were significantly higher in the 25–34, 35–44, and ≥45 age groups. Additionally, the seroprevalence rate of anti-HIV was significantly higher in the 25–34 age group compared to the 18–24 age group (Supplementary Table S3). Over the decade from 2014 to 2023, the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP showed a declining trend across all age groups. Specifically, the decline in HBsAg and anti-HCV seroprevalence rates was largely consistent across different age groups (Figure 3).

Figure 3. 

Seroprevalence rates of (A) HBsAg, (B) HCV, (C) HIV, and (D) TP among blood donors of different age groups in Guangzhou from 2014 to 2023.

Abbreviation: HBsAg=Hepatitis B virus surface antigen; HCV=Hepatitis C virus; HIV=Human immunodeficiency virus; TP=Treponema pallidum; TTIs=Transfusion-transmitted infections.

The seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP were significantly higher in first-time donors compared to repeat donors (Supplementary Table S3). From 2014 to 2023, the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP in first-time donors showed a downward trend, while the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP in repeat donors remained consistently low (Figure 4).

Figure 4. 

Seroprevalence rates of (A) HBsAg (B) HCV (C) HIV (D) TP among blood donors of different donation status in Guangzhou from 2014 to 2023.

Abbreviation: HBsAg=Hepatitis B virus surface antigen; HCV=Hepatitis C virus; HIV=Human immunodeficiency virus; TP=Treponema pallidum; TTIs=Transfusion-transmitted infections.

China has implemented a voluntary blood donation system with routine screening for TTIs, including HBsAg, HCV, HIV, and TP, among all blood donors (4). The prevalence of TTIs directly impacts blood safety, making continuous monitoring essential for effective prevention and control strategies. This study reports the seroprevalence rates and trends of TTIs among 3,111,265 blood donations in Guangzhou from 2014 to 2023, while also investigating variations in seroprevalence across different demographic characteristics.

The overall seroprevalence of TTIs among blood donations in Guangzhou from 2014 to 2023 was 866.21 per 100,000. This differs from findings in other regions of China, such as western China, where the overall prevalence of TTIs among blood donors was 2.67% between 2005 and 2010 (3), and Zhejiang Province, where the prevalence was 1,916.31 per million between 2010 and 2019 (5). These regional variations likely stem from uneven population distributions across China and differences in study periods. Among the TTIs, HBsAg showed the highest seroprevalence (592.46 per 100,000), while anti-HIV had the lowest (19.00 per 100,000), consistent with findings from multiple studies (2-3,5-7). China has a high burden of hepatitis B, with an estimated prevalence of 3% between 2018 and 2022 (8), while the HIV infection rate in the general population is approximately 0.1% (9). The significantly lower seroprevalence of HBV and HIV among blood donors compared to the general population can be attributed to rapid pre-donation testing and the recruitment of donors primarily from low-risk populations. Year-by-year analysis revealed declining trends in the seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP from 2014 to 2023. This contrasts with earlier findings by Li et al. (2000−2010), which showed stable seroprevalence rates of HBsAg, anti-HCV, and anti-HIV among blood donors in Guangzhou, with increasing anti-TP rates. The recent decline highlights the effectiveness of the Chinese government initiatives in infectious disease prevention and control, including routine hepatitis B vaccination for newborns since 1992, free hepatitis B vaccines for all infants since 2002, and antiretroviral drugs for HIV treatment.

This study found that the seroprevalence rates of TTIs are higher among male donors, consistent with previous studies in China. Men exhibit a greater risk for HBV and HCV infections (10). According to research by Chang L et al., male sex is an independent predictor of HIV and syphilis infection among Chinese blood donors (11). Year-by-year analysis revealed that the discrepancy in seroprevalence rates of HBsAg, anti-HCV, anti-HIV, and anti-TP between male and female donors has narrowed. However, in 2023, the seroprevalence rates of HBsAg and anti-HIV remained significantly higher among male donors compared to female donors (Figure 2).

This study also found that among older blood donors, the seroprevalence rates of HBsAg, anti-HCV, and anti-TP were higher. In contrast, the seroprevalence of HIV was notably higher among donors in the 25–34 age group. Song Y et al. reported that higher TTIs prevalence in western China is associated with older age groups (3). It was found that from 2014 to 2017, the seroprevalence rate of anti-TP significantly increased with age among blood donors in Shenzhen (12). However, from 2010 to 2014, the proportion of HIV seroprevalence across different age groups among blood donors in Shiyan, was roughly similar (6). Further, our study showed that seropositive blood donors were predominantly first-time donors. Therefore, establishing a stable pool of regular repeat donors within the voluntary blood donation community enhances blood safety. Repeat donors test negative in previous donations, thus reducing the likelihood of window-period infections. The lower prevalence of repeat-time donors is also linked to blood deferral policies, where donors who test positive twice for TTIs are permanently deferred from future donations.

The key strength of this study is that it is a large-scale retrospective investigation of TTIs among blood donors in Guangzhou, China, and it also analyzes the annual trend of TTIs seroprevalence. However, this study had certain limitations. As a cross-sectional study, it did not include follow-up assessments of seropositive donors; therefore, we could not determine whether these donors had engaged in risk behaviors (such as men who have sex with men or multiple sexual partners). Furthermore, confirmatory tests for anti-HCV, HBsAg, and anti-TP were not performed.

In summary, this study found that the seroprevalence rates of hepatitis B, hepatitis C, HIV, and Treponema pallidum among blood donors were relatively low, and there has been a declining trend in the seroprevalence rate of TTIs over the decade. Upon stratification by demographic characteristics, significant variations in TTIs seroprevalence rates were noted among different donor groups: male donors, first-time donors, and older donors demonstrated higher seroprevalence rates for TTIs. The risk associated with different TTIs varied across genders and age groups. The findings from this study provide robust evidence to support ongoing surveillance of TTIs seroprevalence rates in China, and are instrumental in guiding blood donor screening strategies.