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In the field of distributed medical data storage, relayed data is usually kept centrally on the central node, which may lead to an increased risk of a single point of failure and security challenges from malicious tampering. While introducing backup nodes can partially alleviate these issues, the efficiency of synchronization and switching between nodes remains constrained. In addition, nodes storing relayed data can reach a consensus to modify the forwarded data, which lacks trustworthiness. Given the problems faced by traditional distributed storage in the field of medical data, combined with the characteristics of blockchain technology, we propose a distributed medical data storage model based on blockchain technology, named DDS (Decentralized Distributed Storage), which is intended to be applied in medical data management. In the DDS model, we embed relay data into blocks for storage and ensure the integrity and security of relay data for medical data by introducing redundant blockchain storage and collaborative verification mechanisms. The model is divided into two key phases: the storage phase of relay data of medical data and the verification phase. In the storage phase, the doctor's signature and the associated copy location data are sent to multiple validation nodes, after which the relay data block of medical data is generated and written to the blockchain. In the validation phase, the node first verifies whether the local relay data blockchain state is consistent with the global state. If it is not, a state synchronization operation is performed. Next, the validation node retrieves the local relay data blockchain to verify the integrity of the medical data relay data. From the theoretical analysis and experimental results, the DDS model can ensure the traceability and integrity of relay medical data and has good concurrent processing performance and less impact on the efficiency of medical data storage. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) infection is of high prevalence in China. Mother-to-infant transmission is the major route for HBV transmission and subsequent chronicity. This study aimed to investigate current HBsAg-positive rate among pregnant women and immunoprophylaxis outcome in China. Multicenter prospective study was conducted in 10 centers. From 2008 to 2012, 67,720 pregnant women were screened and 1,150 HBsAg-carrier mothers and their infants aged 8-12 months were studied in four out of all centers, among whom HBV markers (HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb) and HBV DNA (in three centers) were measured. The results showed that HBsAg-positive rate of pregnant women was 6.7 % (4,533/67,720) and infants' immunoprophylaxis failure rate was 3.4 % (39/1,150). Immunoprophylaxis failure infants were all born to mothers of HBeAg-positive and HBV DNA ≥6 log copies/ml. Among infants of HBeAg-positive mothers, multivariable analyses showed the following: mother's age <28 years vs ≥28 years, RR = 0.157, 95 % confidence interval (CI) [0.067, 0.369], p = 0.000; Neonates receiving vaccine vs vaccine plus hepatitis B immune globulin (HBIG), RR = 0.371, 95 % CI [0.167, 0.825], p = 0.015. Pregnant women receiving HBIG in the third trimester, vaginal delivery and breastfeeding had no significant effects on HBV mother-to-infant transmission. Conclusions: Pregnant women are still of high HBsAg prevalence in China. HBV mother-to-infant transmission still occurs after passive-active immunization. Pregnant women of high HBV replication levels are the major risk population of HBV mother-to-infant transmission. Passive-active immunization is necessary for neonates of HBeAg-positive mothers. Mother's age <28 years and neonate receiving vaccine only were the risk factors for HBV mother-to-infant transmission. Breastfeeding did not put children at risk of mother-to-infant transmission. [ABSTRACT FROM AUTHOR]