The current incidence, prevalence, and residual risk of hepatitis B viral infections among voluntary blood donors in China.

BACKGROUND: There are few data available on the prevalence, incidence, and residual risk of transfusion-transmitted HBV (TT-HBV) infections among Chinese blood donors. This study investigated the demographic characteristics of blood donors, as well as the prevalence, incidence, and residual risk (RR) of TT-HBV infections in six large blood centers in different regions of China. METHODS: The demographic characteristics and HBV screening test results of blood donors from six blood centers in different regions in China were collected and analyzed. The hepatitis B surface antigen (HBsAg) yield approach was used to estimate the incidence of HBV. Then, the RR of TT-HBV infections was evaluated using the incidence-window period model. RESULTS: The majority of donors were between 18 and 35 years old (including 35), with the exception of the Changzhi Blood Center where a majority of donors were between 35 and 55 years old (including 55). The prevalences of HBV were 0.13%, 0.078%, 0.16%, 0.07%, 0.20%, 0.25% in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively. The estimated corresponding incidences were 213.44, 161.59, 989.80, 278.05, 125.31 and 352.19 per 105 person-years. Using an infectious window period of 59 days, the RR for HBV was estimated to be 34.14, 25.85, 158.35, 44.48, 20.04 and 56.35 per 105 person-years in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively. CONCLUSION: Despite the introduction of more sensitive assays in blood screening, our data revealed that the current residual risk of TT-HBV infection was still high (overall 56.53 per 105 py). A continuous monitoring of the residual risk of transfusion-transmitted infections is crucial for safe blood management.

The History and Challenges of Blood Donor Screening in China.

Since the establishment of People's Republic of China in 1949, the Chinese government has encountered several catastrophes related to transfusion transmitted diseases. The government's increasing attention to blood safety has prompted the initiation of a series of policies and measures that have enhanced the level of safety for the blood supply and met the basic clinical demands of blood for 1.3 billion people in the country. Blood donation screening strategies in China predominantly comprise donor screening and donor testing. Donor screening includes selection of low-risk blood donors by the use of a donor history questionnaire, predonation physical examination, and initial rapid donor testing. Donor testing includes direct pathogen detection and serology tests. The year 1998 marked the most transformative change in blood donor selection and screening policies in China. Before 1998, paid donation was the predominant mode of blood donation. Donor screening and donor testing were conducted before donation, and only those who were eligible were allowed to donate. To ensure the safety of blood, donor testing was performed again after donation. After the implementation of the Blood Donation Law in 1998, to promote voluntary and unpaid donation, predonation donor testing was eliminated to reduce the amount of waiting time and to provide a more convenient donation experience for blood donors. However, it is the national requirement that donated blood should undergo 2 rounds of testing using different equipment or reagents, conducted by different personnel. Donor selection has transitioned from paid donation and obligatory donation to voluntary donation with fixed volunteer groups, as the latter mode of donation provides the lowest risks. Donations are currently screened for syphilis, hepatitis C virus, HIV, and hepatitis B virus (HBV). Units, previously typed only for ABO, are now routinely tested for both ABO and Rh(D). Innovations in testing technologies and methods have also brought changes to screening parameters. For instance, screening for HBV pathogens evolved from the early use of hemagglutination method to the later use of radioimmunoassay, independent enzyme-linked immunosorbent assay, and now the widespread application of nucleic acid test (NAT). Since 2010, the Chinese government has established NAT capacity in several blood centers; and in 2015, the government invested 900 million RMB on the nationwide expansion of NAT. Although the Chinese government has worked to enhance blood safety, many challenges remain. Concern exists for rising rates of HIV infection. The existence of occult HBV infection and the transmission of emerging blood-borne diseases continue to challenge the safety of the blood supply.