The duration and breadth of antibody responses to 3-dose of inactivated COVID-19 vaccinations in healthy blood donors: An observational study.

Objectives: We aimed to evaluate the duration and breadth of antibodies elicited by inactivated COVID-19 vaccinations in healthy blood donors. Methods: We performed serological tests on 1,417 samples from 658 blood donors who received two (n=357), or three (n=301) doses of COVID-19 inactivated vaccine. We also accessed the change in antibody response before and after booster vaccination in 94 participants and their neutralization breadth to the current variants after the booster. Results: Following vaccination, for either the 2- or 3-dose, the neutralizing antibodies (nAbs) peaked with about 97% seropositivity approximately within one month but subsequently decreased over time. Of plasmas collected 6-8 months after the last immunization, the nAb seropositivities were 37% and 85% in populations with 2-dose and 3-dose vaccinations, respectively. The nAbs of plasma samples (collected between 2-6 weeks after the 3rd dose) from triple-vaccinated donors (n=94) showed a geometric mean titer of 145.3 (95% CI: 117.2 to 180.1) against the ancestral B.1, slightly reduced by 1.7-fold against Delta variant, but markedly decreased by 4-6 fold in neutralizing Omicron variants, including the sub-lineages of BA.1 (5.6-fold), BA.1.1 (6.0-fold), BA.2 (4.2-fold), B.2.12.1 (6.2-fold) and BA.4/5 (6.5-fold). Conclusion: These findings suggested that the 3rd dose of inactivated COVID-19 vaccine prolongs the antibody duration in healthy populations, but the elicited-nAbs are less efficient in neutralizing circulating Omicron variants.

[Epidemiologic Survey of Blood Donors with HBsAg⁻/HBV DNA⁺ in Chinese Xiamen Area].

OBJECTIVE: To understand the characteristics of infections from blood donors with HBsAg⁻/HBV DNA⁺ in Xiamen area. METHODS: Donors in Xiamen area were assayed by routine ELISA and those with negative results were tested by nucleic acid amplification testing (NAT). HBsAg⁻/HBV DNA⁺ samples were tested by quantitative detection of HBV DNA. Epidemiological analysis and following up examination were conducted in HBsAg⁻/HBV DNA⁺ donors. RESULTS: Out of 130659 samples 113 were tested as HBsAg⁻/HBV DNA⁺ and with a rate of 0.09%. Among those, 62 samples were tested by quantitative detection of HBV DNA. All of the quantitative results were less than 1 × 10³ IU/ml and 93.5% (58/62) of which were less than 100 IU/ml. The possitive rate of HBsAg⁻/HBV DNA⁺ donors rose with ages. The possitive rate in male donors was higher than that in female and was lower in highly educated ones. Students and public servants had a lower positive rate. CONCLUSION: The possitive rate of HBsAg⁻/HBV DNA⁺ donors is higher in Xiamen and the distribution of possitive donors has certain epidemiological characteristics. It is necessary to mobilize and recruit more people with a lower rate of HBsAg⁻/HBV DNA⁺ infection.

The prevalence of human T-lymphotropic virus infection among blood donors in southeast China, 2004-2013.

BACKGROUND: The human T-lymphotropic virus type 1 (HTLV-1) which is associated with the diseases of adult T-cell leukemia/lymphoma, HTLV-1 associated myelopathy / tropical spastic paraparesis (HAM/TSP) and HTLV-associated uveitis, can cause transfusion-transmitted infections. Although HTLV screening of blood donors was already routinely performed in developed countries, little is know about the HTLV prevalence among blood donors in developing countries which do not perform HTLV screening, such as China. OBJECTIVES &AIMS: To systematically characterize the prevalence of HTLV infection among bloods in southeast China. METHODS: A 10-year survey for HTLV prevalence in blood donors was performed in Xiamen, southeast China, during 2004-2013. The HTLV-1/2 of blood donations were screened by enzyme-linked immunosorbent assay, following with confirmation by western blot assay and 9nucleic acid testing. The HTLV-1 prevalences in donors from different cities were calculated. Viral sequences derived from identified HTLV-positive cases were sequenced and analyzed. RESULTS: Among 253,855 blood donors, 43 were confirmed to be seropositive for HTLV-1 (16.9 per 100,000 95% CI: 12.3-22.8) and none HTLV-2 infection was found. The HTLV-1 prevalence varied significantly in donors from different cities. Donors from cities in Fujian province (24.3 per 100,000, 95%CI: 17.4-33.1) had a significantly higher (p=0.001) HTLV-1 seroprevalence than those who were born in non-Fujian cities (3.4 per 100,000, 95%CI: 0.7-9.8). Among nine cities in Fujian province, the highest prevalence was found in blood donors from Ningde (171.3 per 100,000, 95%CI: 91.3-292.8) which is a coastal city in the northeast of Fujian. Molecular characterization of viral sequences from 27 HTLV-1 carriers revealed 25 were Transcontinental subtype of genotype A and 2 were Japanese subtype of genotype A. Interestingly, 12 of 25 Transcontinental subtype sequences harbored a characteristic L55P mutation in viral gp46 protein, which was only presented in the Transcontinental subtype sequences from Japan and Taiwan but not in that from other countries. CONCLUSIONS: Although China is considered to be a non-endemic region for HTLV, the HTLV-1 prevalence in blood donors is significantly higher in Fujian province, southeast China. A higher prevalence of HTLV-1 in the Fujian may be attributed to endemic foci in the city of Ningde.

Molecular characteristics of occult hepatitis B virus from blood donors in southeast China.

The characteristics of 30 carriers with occult hepatitis B virus (HBV) infection (OBI) were compared with those of 30 individuals diagnosed as being HBV carriers at the time of blood donation, 60 asymptomatic carriers, and 60 chronic hepatitis patients. The prevalence of genotype C was significantly higher in carriers with OBIs than in any other HBsAg-positive (HBsAg(+)) group (P < 0.001). Specific amino acid substitutions in the regions from amino acids 117 to 121 and amino acids 144 to 147 located in the major hydrophilic region of the S gene were associated with carriers with OBIs (P < 0.01 for carriers with OBIs versus HBsAg(+) donors, carriers with OBIs versus HBsAg(+) asymptomatic carriers, and carriers with OBIs versus HBsAg(+) chronic hepatitis patients). G145R was the major variation in the HBV isolates responsible for local occult HBV infections.

[Surveillance for occult HBV infection and HBsAg variants in blood donors].

Occult hepatitis B virus (HBV) infection status of blood donors in a southern city in China was investigated by immunological assays and nucleic acid testing. Overall, 17 (0.19%, 95% CI: 0.11%-0.30%) of the 9023 HBsAg negative samples were found to be positive for the presence of HBV DNA. "A" epitope sequences were obtained from 14 among them. Mutation(s) in aa124-aa147 existed in 6 (42.9%, 6/14) samples and 4 (66.7%, 4/6)were G145R mutation. Ratio of genotype C in occult donors (10/17) was statistically higher than HBs-positive donors (0/15, P<0.01), which implied that HBV genotype C leaded to occult infection more easily.