[Persistence follow-up of immune memory to hepatitis B vaccine among infants with non- and low-response to primary vaccination after revaccination with three doses].

This study followed up the immune memory after 3-dose revaccination among infants with non-and low-response following primary hepatitis B (HepB) vaccination. About 120 children without self-booster doses were finally included who had anti-HBs<10 mIU/ml (anti-HBs negative) at the time of follow-up, of whom 86 children completed blood sampling and anti-HBs testing. Before the challenge dose, all 86 children were negative for anti-HBs, and the GMC of anti-HBs was<10 mIU/ml. The seropositive conversion rate of anti-HBs was 100% and the GMC of anti-HBs was 886.11 (95%CI: 678.15-1 157.84) mIU/ml after the challenge dose. Compared with those with GMC<7 mIU/ml before the challenge dose, infants with GMC>7 mIU/ml had a higher anti-HBs level after the challenge dose. The ß value (95%CI) was 0.82 (0.18-1.46) (P=0.012). Compared with those with GMC<1 000 mIU/ml at primary vaccination, infants with GMC≥1 000 mIU/ml had a higher anti-HBs level after the challenge dose. The ß value (95%CI) was 0.78 (0.18-1.38)(P=0.012). The results showed a stronger immune memory was found at 9 years after revaccination among infants with non-and low-response to HepB.

[Clinicopathological and prognostic features of subungual melanoma in situ].

Objective: To investigate the clinicopathological characteristics, immunohistochemical profiles, molecular features, and prognosis of subungual melanoma in situ (SMIS). Methods: Thirty cases of SMIS were collected in Fudan University Shanghai Cancer Center, Shanghai, China from 2018 to 2022. The clinicopathological characteristics and follow-up data were retrospectively analyzed. Histopathologic evaluation and immunohistochemical studies were carried out. By using Vysis melanoma fluorescence in situ hybridization (FISH) probe kit, combined with 9p21(CDKN2A) and 8q24(MYC) assays were performed. Results: There were 8 males and 22 females. The patients' ages ranged from 22 to 65 years (median 48 years). All patients presented with longitudinal melanonychia involving a single digit. Thumb was the most commonly affected digit (16/30, 53.3%). 56.7% (17/30) of the cases presented with Hutchinson's sign. Microscopically, melanocytes proliferated along the dermo-epithelial junction. Hyperchromatism and nuclear pleomorphism were two of the most common histological features. The melanocyte count ranged from 30 to 185. Most cases showed small to medium nuclear enlargement (29/30, 96.7%). Pagetoid spread was seen in all cases. Intra-epithelial mitoses were identified in 56.7% (17/30) of the cases. Involvement of nailfold was found in 19 cases, 4 of which were accompanied by cutaneous adnexal extension. The positive rates of SOX10, PNL2, Melan A, HMB45, S-100, and PRAME were 100.0%, 100.0%, 96.0%, 95.0%, 76.9%, and 83.3%, respectively. FISH analysis was positive in 6/9 of the cases. Follow-up data were available in 28 patients, and all of them were alive without disease. Conclusions: SMIS mainly shows small to medium-sized cells. High melanocyte count, hyperchromatism, nuclear pleomorphism, Pagetoid spreading, intra-epithelial mitosis, nailfold involvement, and cutaneous adnexal extension are important diagnostic hallmarks. Immunohistochemistry including SOX10 and PRAME, combined with FISH analysis, is valuable for the diagnosis of SMIS.

[Anti-HBs persistence after primary vaccination with three doses of 5 µg recombinant hepatitis B vaccine among normal and high-responder infants: 10-year of follow-up].

Objective: Assess the 10-year Immune persistence and the predictors after primary vaccination hepatitis B vaccine (HepB) among normal and high-responder infants. Methods: A total of 1 838 Infants of 7-12 months old located in Jinan, Weifang, Yantai and Weihai of Shandong Province who were induced normal or high antibody response (anti-HBs titer ≥ 100 mIU/ml) after primary vaccination (three dose with 0-1-6 procedure) with 5 µg recombinant HepB among newborns were included in the study, in 2009. 3 ml of venous blood samples were collected at baseline survey (T0) and antibodies against hepatitis B surface antigen (anti-HBs), antibody against hepatitis B core antigen (anti-HBc) and hepatitis B surface antigen (HBsAg) were detected using chemiluminescence microparticle immunoassay (CMIA) method. A self-designed questionnaire was used to collect information including the infant's age, sex, birth weight, premature birth, birth number, delivery location and mother's HBV infection status. In 2014 (followed up for 5 years) and in 2019 (followed up for 10 years) (T1), 2 ml of venous blood samples were collected. Anti HBS and anti HBC were detected by CMIA method. Those with anti HBS<10 mIU/ml were detected by CMIA method. Multivariate unconditional logistic and linear regression models were used to analyze the influencing factors of anti-HBs positive rate and geometric mean concentration (GMC) at T1. Results: After 10 years follow-up, 73.94% of the subjects (1 359/1 835) finished the follow-up. 51.15% of the subjects, a total of 625 were boys. The positive rate of anti-HBs was 100% at T0 and decreased to 53.44% (95%CI: 50.59%-56.26%) at T1. The average annual decline rate of anti-HBs positive rate from T0 to T1 was 6.07%. The GMC of anti-HBs decreased from 607.89 (95%CI: 579.01-642.62) mIU/ml to 16.44 (95%CI: 15.06-18.00) mIU/ml. The average annual decline rate of anti-HBs GMC in 10-year follow-up was 30.30%. Multivariate logistic analysis showed that the positive rate of anti-HBs at T1 was lower in those who did not vaccinate the first dose in time (OR=0.25, 95%CI:0.07-0.71). Compared with those with GMC<1 000 mIU/ml at T0, those with GMC ≥ 1 000 mIU/ml had a higher positive rate of anti-HBs at T1 (OR=2.29, 95%CI:1.76-2.97). Multivariate regression analysis showed that the GMC of anti-HBs at T1 was lower in those who did not vaccinate the first dose in time (ß=-0.50, 95%CI:-1.24-0.24). Compared with those with GMC<1 000 mIU/ml at T0, those with GMC ≥ 1 000 mIU/ml had a higher GMC of anti-HBs at T1 (ß=0.81, 95%CI: 0.62-1.05). Conclusion: Anti-HBs GMC decreased in 10 years after primary vaccination of 5 µg recombinant hepatitis B vaccine among normal and high-responders. The anti-HBs persistence was mainly associated with whether the first dose was vaccinated in time and the level of anti-HBs at the end of primary vaccination.

[Analysis of capability to pertussis etiology and serological diagnosis for Gradeâ ¡ and â ¢medical institutions in Shandong Province in 2018].

Objective: Investigate and analyze the etiology and serological diagnosis capabilities of pertussis in medical institutions in Shandong Province in 2018. Methods: Using the census method, a questionnaire survey was conducted among 603 second and above level medical institutions in Shandong Province. The deadline for the survey was December 2018, and a total of 543 questionnaires have been recovered, and the validity rate of the questionnaires was 90%. Surveyed the pertussis etiology and serology test items (pertussis IgM and IgG, pertussis nucleic acid and pertussis bacterial culture) and the start time of each test item by questionnaire. The reported cases (confirmed cases and clinically diagnosed cases) between January 1, 2012 and December 31, 2018 were derived from the Chinese Disease Control and Prevention Information System according to the onset date. We used indicators such as fixed-base development speed, chain development speed, and chain growth speed for analysis. The chi test was used to analyze the differences in the composition ratio of medical institutions with detection ability in different levels and regions, and analyze the changes in the number of reported cases before and after the development of pertussis etiology and serology testing. Results: A total of 543 medical institutions accounted for 90.0% (543/603) of all secondary and above level medical institutions in the province, 356 secondary medical institutions (65.6%), and 187 tertiary medical institutions (34.4%). There were 10 medical institutions that carry out pertussis IgM, IgG and nucleic acid testing, accounting for 1.8% (10/543) of the surveyed medical institutions respectively. 2 medical institutions that carried out bacterial culture, accounting for 0.4% of the surveyed medical institutions (2/543). 20 medical institutions have carried out the above tests (8 secondary medical institutions and 12 tertiary medical institutions), accounting for 3.7% (20/543). The proportion of tertiary medical institutions with pertussis IgM, IgG detection and nucleic acid detection capabilities [6.42% (12/187)] was significantly higher than that of secondary medical institutions [2.25% (8/356)] (χ²=6.01, P=0.014). From 2012 to 2018, the fixed base ratio development speed of reported cases was 3 834.69% in Shandong Province, among which medical institutions with etiology and serological testing capabilities reached 4 533.33%. In 13 medical institutions, the average annual number of reported cases after pertussis etiology and serological testing were higher than that of reported cases before testing. Conclusion: The ability of pertussis etiology and serology diagnosis of secondary and above medical institutions in Shandong Province needs to be improved.

[Efficacy and safety of neoadjuvant apatinib in combination with dose-dense paclitaxel and carboplatin in locally advanced triple negative breast cancer patients].

Objective: To observe the short-term efficacy and safety of apatinib in combination with dose-dense paclitaxel and carboplatin in locally advanced triple-negative breast cancer (TNBC) patients. Methods: From September 2018 to September 2019, 17 stage Ⅱ/Ⅲ TNBC patients were enrolled in this single arm, single center prospective phase Ⅱ study. They received neoadjuvant treatment of apatinib 250 mg per day, paclitaxel 175 mg/m(2) on 1(st) day and a dose of carboplatin according to the area under curve (AUC)=4 on 2(nd) day, every 14 days as a cycle. Results: By January 2020, 16 cases completed 4-7 cycles of apatinib treatment and 4-8 cycles of chemotherapy. The median cycles of apatinib treatment and chemotherapy were 5 cycles and 6 cycles, respectively. Two cases achieved complete responses (CR), 12 achieved partial responses (PR), 2 achieved stable diseases (SD) and no progressive disease was observed. The objective response rate (ORR) was 87.5%, disease control rate (DCR) was 100%. By January 2020, among 12 patients who received surgery, 8 achieved pathologic complete response (pCR, 66.7%). The grade Ⅲ/Ⅳ adverse events included: neutropenia, thrombocytopenia in 3 cases (18.8%) each, anemia, fatigue, arrhythmia and alanine aminotransferase (ALT) elevation in 1 case each. Apatinib was interrupted in 5 cases, and was discontinued in 3 cases; chemotherapy dosage was reduced in 1 case. Conclusion: Apatinib in combination with dose-dense paclitaxel and carboplatin neoadjuvant therapy are effective and well tolerated in locally advanced TNBC patients.

[Genotype distribution and molecular epidemiology of hepatitis E virus isolated in Shandong Province of China in 2017].

Objective: To understand the genotype distribution and molecular epidemiological characteristics of hepatitis E virus (HEV) isolated in Shandong Province, 2017. Methods: The cases of hepatitis E who were reported to the National Notifiable Disease Reporting System (NNDRS) from January to December 2017 in Shandong Province were chosen as the subjects in the study. Epidemiological information and blood samples were collected from 1 045 participants. Both anti-HEV IgM and anti-HEV IgG were detected using ELISA method. Viral nucleic acids were extracted only from those of anti-HEV IgM positive samples. Nested reverse transcription-polymerase chain reaction was carried out to amplify 644 bp nucleotide sequences within HEV open reading frame (ORF) 2 region. The sample sequences together with reference sequences from GenBank were subjected to phylogenetic analysis. Results: In total, 638 (61.1%) cases were detected positive for anti-HEV IgM. The average age of male was (57.9±12.2) years, and the anti-HEV IgM positive rate was 61.5% (496/807). The average age of female was (58.1±15.0) years, and the anti-HEV IgM positive rate was 59.7% (142/238). A total of 163 HEV strains were detected, and the positive rate was 25.6% (163/638). The positive rate of the eastern, central and western region was 23.0% (71/309), 33.6% (72/214) and 17.4% (20/115), respectively. Phylogenetic tree and homology analysis indicated that all isolates belonged to genotype Ⅳ, clustering into four different subgenotype (4a, 4b, 4d and 4h). Subgenotype 4d was predominant, accounting for 85.9% (140 strains), followed by 4b (7.4%, 12 strains), 4a (3.7%, 6 strains) and 4h (3.1%, 5 strains). The 4a, 4b, and 4h subgenotype were mainly detected in the eastern region, accounting for 3/5, 11/12, and 4/6, respectively. The 4d subgenotype was mainly in the middle region, accounting for 50.0% (70/140). The homology analysis showed that the 163 sequences shared 82.7% to 100.0% nucleotide sequence identity with each other. The 140 sequences of HEV 4d strains showed high similarity with swine-origin HEV（KF176351）, cattle-origin HEV（KU904278）and sheep-origin HEV（KU904267）isolated in Shandong Province, and the nucleotide homology was 93.1%-98.3%, 92.7%-97.9% and 92.7%-97.9%, respectively. Conclusion: HEV genotype Ⅳ(4d subgenotype) was dominant in Shandong province. A complicated interspecies transmission might be the main source of human HEV infection in Shandong Province, China.

[Persistence of immune memory and its related factors at 12 years after hepatitis B vaccination among adults].

Objective: To estimate the immune memory at 12 years after hepatitis B vaccination and its risk factors among adults. Methods: The study was conducted in 20 villages of Qudi town in Jiyang county, Shandong province, China in 2003. Hepatitis B surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were tested for all healthy residents aged 15-40 years in these villages. Those who had no history of hepatitis B vaccination and were negative for all three indicators were divided into two groups randomly. Hepatitis B vaccine (HepB) was administrated to them on 0-6 month schedule or 0-1-6 month schedule respectively. Blood samples were obtained at one month after the last dose for each receipt and were quantitatively detected for anti-HBs. Finally a total of 629 participants completed HepB vaccination and anti-HBs testing, including 288 of two-dose group and 341 of three-dose group respectively. In 2015, an additional dose of HepB (challenge dose) was administrated to those who were negative for anti-HBs at follow-up (anti-HBs <10 mIU/ml) to evaluate the immune memory. A total of 93 blood samples, including 50 of two-dose group and 43 of three-dose group respectively, were drawn at 14 days after the challenge dose and anti-HBs was quantitatively detected. The anti-HBs geometric mean concentrations (GMCs) after the challenge dose were compared between the two groups. Multivariate linear regression model was built to find the independent risk factors associated with immune memory response (anti-HBs GMC after the challenge dose). Results: The challenge dose of HepB and post-challenge anti-HBs detection were completed among 93 participants. Totally 92 (98.92%, 92/93) participants were found holding immune memory (anti-HBs after the challenge dose was ≥10 mIU/ml). The immune memory positive rates were 100% (50/50) and 97.67% (42/43) in the two-dose group and three-dose group respectively and the corresponding anti-HBs GMC after challenge dose were 2 684.30 (95%CI: 1 721.71-4 185.08) mIU/ml and 3 527.48 (95%CI: 2 145.15-5 800.58) mIU/ml (P=0.410). The anti-HBs GMC after the challenge dose were 1 908.33 (95%CI: 1 190.01-3 060.27) mIU/ml, 4 004.20 (95%CI: 2 257.90-7 101.12) mIU/ml and 8 682.16 (95%CI: 5 813.94-12 965.36) mIU/ml among the participants whose anti-HBs titer was<4, 4-6 and 7-9 mIU/ml at follow-up, respectively (P=0.002). There was no correlation between immune schedule and anti-HBs GMC after the challenge dose; ß (95%CI) was -0.07 (-0.34-0.20), P=0.601. Conclusion: The immune memory after primary hepatitis B vaccination lasted for at least 12 years among adults. The immune memory response was independently associated with ant-HBs titer at follow-up, but might be similar between 0-6 month schedule and 0-1-6 month schedule.

[Application of sentinel lymph node biopsy in patients with melanoma].

Objective: To investigate the difference between routine hematoxylin-eosin (HE) staining and immunohistochemistry in diagnosing metastatic melanoma in sentinel lymph node (SLN) metastases, and to evaluate the association of SLN tumor burden with the status of non-sentinel lymph nodes (NSLN). Methods: 126 melanoma patients were treated with SLN biopsy and further examined with immunohistochemistry at Fudan University Shanghai Cancer Center between 2010 and 2016, and the status of SLN was respectively estimated by HE stain and immunohistochemistry (S-100 protein, HMB45, Melan A and SOX10). In 39 patients who were treated with complete lymph node dissection, characteristics of SLN tumor burden (maximum diameter of the tumor deposit, tumor penetrative depth and the microanatomic location of the metastasis) and the associations of SLN tumor burden with the involvement of NSLN were all evaluated. Results: Of the total 126 cases, 33 (26.2%) were positive by HE staining and 49 (38.3%) were positive by immunohistochemistry. S-100 protein was positive in 48 out of 49 cases (98.0%). HMB45 was positive in 46 out of 49 cases (93.9%). Melan A was positive in 47 out of 49 cases (96.0%). SOX10 was positive in 8 out of 8 cases. The outcome indicated that the application of immunohistochemistry identified positive SLN missed by HE stain in about 12.1% of cases. Of the 39 patients who were treated with complete lymph node dissection, six showed metastases in NSLN. The frequency of metastases in NSLN was 15.4% (6/39) when SLN was positive. Additionally, the frequency of metastases in NSLN in cases with SLN metastatic deposits ≤2 mm was significantly lower than that in cases with SLN metastatic deposits >2 mm; eight cases with SLN metastatic deposits <0.2 mm had no additional positive NSLN. Conclusions: The findings suggest that immunohistochemistry could effectively improve the detection of positive SLN in melanoma. Cases with SLN metastatic deposits ≤2 mm are less likely to have further metastases in NSLN. There is a need for prospective large-population based studies to identify a subgroup of SLN positive patients who can safely be spared complete lymph node dissection.

[Hepatitis B prevalence among women in child-bearing age in Shandong Province, China, 2014].

Objective: To know the prevalence of hepatitis B virus (HBV) among women in child-bearing age in Shandong Province, China, providing references to the improvement of HBV control strategy. Methods: The participants were randomly selected by two-stage sampling method from 12 counties which were representative for the whole province. Firstly two townships were selected from each county by probability proportional to size sampling (PPS) method. Then participants aged 1-4 years, 5-14 years, 15-29 years and 30-59 years were selected by stratified random sampling method. The women in child-bearing age (20-49 years) were involved in this study. Questionnaire survey and 5 ml blood collection were conducted among all participants. Blood samples were detected for hepatitis B surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc). Those who were positive for HBsAg were further detected for hepatitis e antigen (HBeAg), antibody against HBeAg (anti-HBe) and the load of HBV DNA. The basic information of the participants including age, gender, occupation, nationality and residence place were collected. The prevalence of HBV infection indicators after weight adjustment were calculated and compared between participants with different demographic characteristics. Results: A total of 1 151 women in child-bearing age were involved in this study. Twenty-seven participants were positive for HBsAg and the prevalence rate was 2.10% (95% CI: 0.97%-3.23%). Five participants were positive for both HBsAg and HBeAg and the prevalence rate was 0.36% (95% CI: 0-0.84%). There were 567 and 291 participants who were positive for anti-HBs and anti-HBc respectively and the corresponding prevalence rates were 47.72% (95%CI: 41.68%-53.75%) and 24.40% (95% CI: 18.50%-30.30%). The number of participants susceptible for HBV was 527 and the percentage of HBV susceptible women was 47.55% (95% CI: 41.63%-53.47%). Conclusion: HBV infection among women in child-bearing age has attained very low level in Shandong Province, China. However, the high proportion of women in child-bearing age were still susceptible for HBV and hepatitis B immunization should be improved among them.

[Prevalence of hepatitis A antibody among population covered by different hepatitis A immunization strategies in Shandong Province, 2015, China].

Objective: To evaluate prevalence of hepatitis A antibody (anti-HAV IgG) among population covered by different hepatitis A vaccine immunization strategies in Shandong Province in 2015. Methods: In October 2015, according to the geographical location of Shandong Province, the stratified random sampling method was used to stratify the 17 municipal distrcts, and the random number table method was used for sampling, First, two eastern cites (Qingdao, Rizhao), two western cities (Liaocheng, Zaozhuang) and three central cities (Jinan, Zibo and Laiwu) were selected; secondly, one county was drawn from each city. Finally, the participants were divided into five age groups including ≤7 years (age group covered by free hepatitis A vaccination strategy), 8-11 years (age group who receive hepatitis A vaccination at their own charge), 12-24 years (age group covered by catch-up vaccination of hepatitis A), 25-34 years (age group born before hepatitis A vaccine was used) and ≥35 years (age group born before hepatitis A vaccine was used). After all the paticipants or their guardians asked and registered basic information such as age, gender, home address, blood samples were collected from them and anti-HAV IgG was detected by ELISA method. The positive rate of anti-HAV IgG and 95%CI were calculated. Results: A total of 1 654 participants were involved in the final analysis, including 856 males (51.75%) and 798 females (48.25%) whose mean age was (13.44±13.06) years. The crude positive rate of anti-HAV IgG was 91.41% (1 512/1 654, 95%CI: 89.96%-92.72%) and the age-adjusted rate was 90.93% (95%CI: 90.92%-90.94%). The positive rates of anti-HAV IgG was at the highest level in the age group of ≤7 years (95.90%, 95%CI: 95.88%-95.91%) and was at the lowest level in the age group of 25-34 years (83.23%, 95%CI: 83.21%-83.25%). The age-specific positive rates of anti-HAV IgG in eastern areas (96.79%, 95%CI: 96.78%-96.80%) were higher than those in both middle areas (86.66%, 95%CI: 86.65%-86.67%) and western areas (91.96%, 95%CI: 91.95%-91.97%). Conclusion: The positive rate of anti-HAV IgG was high among the general population in Shandong Province, but relatively low among young and middle-aged adults. Besides the routine immunization of hepatitis A among the children, more efforts should be taken for the prevention and control of hepatitis A among young and middle-aged adults in Shandong Province, especially in central and western areas.

[A sero-epidemiological study of hepatitis E among general population in Shandong Province of China in 2014].

Objective: To analyze the sero-epidemiological characteristics of hepatitis E virus (HEV) in Shandong province, and thereby to provide evidence for the policy-making of hepatitis E prevention and control. Methods: The inhabitants aged between 1-59 years old were randomly selected to participate in the study by two-stage stratified random sampling method from 12 counties in Shandong province in October, 2014. Firstly two townships were selected from each county by probability proportional to size sampling (PPS) method. A total of 5 229 participants aged 1-59 years old were selected by stratified random sampling method. All the participants finished a questionnaire survey and a venous blood sample (3-5 ml) was collected from each to test anti-HEV IgG by enzyme-linked assay (ELISA). The weighted prevalence of anti-HEV IgG with different demographic characteristics was estimated. The variance of the positive rate of anti-HEV IgG was calculated by Taylor series linearization method, as well as its 95%CI. A statistical test was conducted to compare the rate of its 95%CI, and the results in the present study were compared with those in sero-survey in 2006. Results: A total of 5 229 subjects entered the final analysis in 2014. The overall weighed prevalence of anti-HEV IgG was 9.19% (95%CI: 6.18%-12.20%) among natural population in Shandong province, decreased by 19.88% in comparison with that in 2006 sero-survey (11.47%, 95%CI: 8.92%-14.02%). The prevalence increased with age increasing (χ(2trend)=288.11, P<0.001) in 2014, which was similar to the result in 2006 sero-survey. Except for 1-4 years old group, the prevalence of anti-HEV IgG in the other age groups were lower than it in the corresponding groups in 2006. The prevalence of anti-HEV IgG in urban (8.19%, 95%CI: 0.00-22.23%), rural areas (9.69%, 95%CI: 4.99%-14.38%), eastern areas (12.70%, 95%CI: 0.00-27.72%), central areas (4.74%, 95%CI: 0.00-9.91%) and western areas (9.32%, 95%CI: 0.69%-17.94%) in 2014 were all lower than the corresponding prevalences (11.39%, 95%CI: 8.17%-14.62%; 11.92%, 95%CI: 8.75%-15.08%; 22.77%, 95%CI: 14.99%-30.55%; 7.97%, 95%CI: 4.75%-11.20%; 10.59%, 95%CI: 6.37%-14.82%) in 2006 survey. The prevalence of anti-HEV IgG in coastal areas (16.56%, 95%CI: 12.94%-20.18%) and inland areas (7.63%, 95%CI: 5.16%-10.10%) in 2014 were lower than it in the corresponding areas (28.04%, 95%CI: 20.45%-35.64%; 9.50%, 95%CI: 7.31%-11.70%) in 2006 survey. The prevalence among peasant (11.98%, 95%CI: 8.20%-15.76%), worker (9.68%, 95%CI: 4.48%-14.88%), cadre (13.90%, 95%CI: 7.47%-20.33%), service provider (12.26%, 95%CI: 1.80%-22.73%) in 2014 survey were lower than it among the corresponding populations (13.76%, 95%CI: 10.15%-17.38%; 21.11%, 95%CI: 12.67%-29.55%; 17.81%, 95%CI: 7.63%-28.00%; 21.08%, 95%CI: 0.03%-42.12%) in 2006 survey. Conclusion: The prevalence of anti-HEV IgG has decreased in Shandong province in the recent years, but the epidemiological characteristics found no obvious changes. HEV susceptibility in natural population was generally high. Hepatitis E vaccines were recommended to be used in HEV high-risk population in the province.

[Anti-HBs persistence after revaccination with three doses of hepatitis B vaccine among low-responder infants following primary vaccination: 4-year of follow-up].

Objective: Assess the 4-year antibody against hepatitis B surface antigen (anti-HBs) persistence after revaccination with 3-dose of hepatitis B vaccine (HepB) among low-responder infants following primary vaccination. Methods: According to stratified cluster sampling, a total of 4 147 infants were enrolled and primarily vaccinated with 5 µg HepB derived in Saccharomyces Cerevisiae (HepB-SC) at 0-1-6 months schedule from 75 towns of Jinan, Weifang, Yantai, Weihai prefectures, Shandong Province, China in Aug and Sep 2009. Blood samples were collected one to six months after the third dose of primary immunization and tested for anti-HBs using chemiluminescence microparticle immunoassay (CMIA). 717 infants who appeared low response (10 mU/ml ≤ anti-HBs<100 mU/ml) were revaccinated with 3-dose of HepB. Blood samples were collected from a total of 315 infants one month (T(0)), four years (T(1)) after revaccination and anti-HBs, antibody against hepatitis B core antigen (anti-HBc) and hepatitis B surface antigen (HBsAg) were detected by CMIA. Information about their birth, primary vaccination were collected. The risk factors associated with positive rate of anti-HBs and GMC of anti-HBs were identified by multiple non-conditional logistic regression analysis and multifactor linear regression model analysis, respectively. Results: Among 315 children, 165 (52.38%) were male and 150 (47.62%) were female. The positive rate was 83.81% (264/315) at T(0) and it decreased to 16.51% (149/529) at T(1). The corresponding GMC decreased from 473.15 mU/ml to 17.37 mU/ml. The average annual decreasing rate of positive rate and GMC was 33.38% and 56.23% from T(0) to T(1). Multivariable analysis showed the positive rate and GMC among those whose anti-HBs titer higher at T(0) were significantly higher at T(1). The positive rate at T(1) among those whose anti-HBs titer 400-<600, 600-<800, 800-<1 000, ≥1 000 mU/ml at T(0) were significantly higher than those whose anti-HBs titer less than 200 mU/ml. The OR (95%CI) of the positive rate was 4.29 (1.03-17.84), 4.53 (1.25-16.47), 4.19 (1.10-15.97) and 9.13 (2.91-28.63), respectively. The GMC at T(1) among those whose anti-HBs titer 400-<600, 600-<800, 800-<1 000 mU/ml and those whose anti-HBs titer ≥1 000 mU/ml at T(0) were higher than those whose anti-HBs titer<200 mU/ml. The b value (95% CI) of GMC was 0.84 (0.06-1.62), 1.13 (0.46-1.79), 1.33 (0.65-2.01) and 1.88 (1.33-2.44), respectively. GMC among full-term infants were significantly higher than premature infants at T(1). The b value (95% CI) of GMC was 0.86 (0.04-1.68). Conclusion: Anti-HBs GMC decreased rapidly 4 years after revaccination among low-responder infants, but still kept good protection. The anti-HBs persistence after revaccination was associated with anti-HBs level of titer one month after revaccination.

[Utility and evaluation of immunohistochemical detection of BRAF V600E mutation in melanoma].

Objective: To evaluate the sensitivity, specificity and clinical value of anti-BRAF V600E antibody (clone VE1) in detection of the BRAF V600E mutant in formalin-fixed and paraffin-embedded (FFPE) melanoma specimens by immunohistochemical (IHC) methods. Methods: A total of 50 melanoma samples collected between 2008 and 2016 from 40 patients were analyzed for BRAF mutation (exon 15) by DNA sequencing using FFPE. These tissues were immunostained with VE1 antibody, and the results were analyzed and compared with those by DNA sequencing. Results: By DNA sequencing, 36 cases showed BRAF mutation while others were BRAF wild type. Among the 36 cases with BRAF mutation, 32 harbored BRAF V600E, two harbored BRAF V600K, one had BRAF K601E and one had BRAF D594N, respectively. IHC staining showed 30 specimens were VE1 positive, while 19 were negative. The determination of IHC result for one case was obscured by heavy pigments. Of the BRAF-mutated specimens, four specimens with BRAF mutation other than V600E were all negative for VE1. The sensitivity and specificity of the VE1 immunostaining was 96.8% and 100.0% respectively.Concordance of BRAF V600E detection between immunostaining and DNA sequencing was 98.0%(48/49). Conclusions: High sensitivity and specificity for VE1 immunostaining in detecting BRAF V600E in melanomas are demonstrated. It is a rapid and cost-effective method for detecting BRAF V600E mutations in melanoma patients. Hence, VE1 immunostaining can be used as an important screening method for BRAF mutation in laboratories.

[Anti-HBs persistence following primary vaccination with three doses of hepatitis B vaccine among normal and high-responder adults: a 3-year follow-up study].

OBJECTIVE: To assess the 3-year anti-HBs persistence after primary vaccination with three-dose of hepatitis B vaccine (HepB) among normal and high-responder adults. METHODS: A total of 24 237 healthy adults who had no histories of hepatitis B infection and hepatitis B vaccination, resided in local areas for more than six months and were aged 18-49 years were selected from 79 villages of Zhangqiu county, Shandong province, China in 2009. Blood samples were obtained and hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected using ELISA method. A total of 11 590 persons who were negative for all of these indicators were divided into four groups by cluster sampling method. Each group was vaccinated with one of the following four types of HepB at 0-1-6 months schedule: 20 µg HepB derived in Saccharomyces cerevisiae (HepB-SC), 20 µg HepB derived in Chinese hamster ovary cell (HepB-CHO), 10 µg HepB-SC and 10 µg HepB derived in Hansenula polymorpha (HepB-HP). Blood samples were collected one month after the third dose of primary immunization and tested for anti-HBs using chemiluminescence microparticle immunoassay (CMIA). During the follow-up to normal and high-responders, the following information was collected: the demographic characteristic (including age and gender), histories of hepatitis B infection, hepatitis B vaccination, smoking, drinking and chronic diseases. Blood samples were collected one month (T1) and three years after primary vaccination (T2) and anti-HBs, anti-HBc and HBsAg (if anti-HBs<10 mU/ml) were detected by CMIA. The risk factors associated with positive rate of anti-HBs and GMC of anti-HBs were identified by multiple logistic regression analysis and multifactor linear regression model analysis, respectively. RESULTS: A total of 4 677 normal and high-responders were identified. Among 4 677 participants, 2 014 (43.06%) were males and 2 663 (56.94%) were females. The positive rate was 100% at T1 and it decreased to 80.99% (3 788/4 677) three years after vaccination. The corresponding GMC was decreased from 1 413.48 (95%CI: 1 358.86-1 470.30) mU/ml to 60.33 (95%CI: 56.97-63.90) mU/ml. When comparing with those vaccinated 20 µg HepB-CHO, the significantly lower positive rate of anti-HBs three years after vaccination was observed in those vaccinated 20 µg HepB-SC, 10 µg HepB-SC and 10 µg HepB-HP. The OR (95%CI) was 0.65 (0.50-0.84), 0.52 (0.41-0.67) and 0.31 (0.28-0.45), respectively. The GMC of anti-HBs was also significantly lower among those vaccinated 20 µg HepB-SC, 10 µg HepB-SC and 10 µg HepB-HP. The b (95%CI) was -0.33 (-0.47- -0.20), -0.41 (-0.55- -0.28) and -0.78 (-0.92- -0.65), respectively. The GMC of anti-HBs in those aged 30-39 years old and 40-49 years old were lower than that in 18-29 years. The b (95%CI) was -0.31 (-0.47- -0.15) and -0.24 (-0.39- -0.09), respectively. When comparing with those whose anti-HBs titer was less than 999 mU/ml at T1, the significantly higher positive rate of anti-HBs three years after vaccination was observed in those whose anti-HBs titer was 1 000-1 999 mU/ml, those whose anti-HBs titer was 2 000-9 999 mU/ml and those whose anti-HBs titer was ≥10 000 mU/ml. The OR (95%CI) was 4.97 (3.80-6.49), 7.87 (16.19-10.01) and 9.67 (6.47-14.44), respectively. When comparing with those whose anti-HBs titer was ≤999 mU/ml at T1, the GMC of anti-HBs three years after vaccination was also significantly higher among those whose anti-HBs titer at T1 was 1 000-1 999 mU/ml, those whose anti-HBs titer at T1 was 2 000-2 999 mU/ml and those whose anti-HBs titer at T1 was ≥10 000 mU/ml. The b (95%CI) was 1.00 (0.87-1.14), 1.85 (1.74-1.97) and 3.28 (3.12-3.44), respectively. Four subjects showed HBsAg seroconversion and anti-HBc conversion rate was 4.68% at T2. CONCLUSIONS: Anti-HBs GMC decreased rapidly three years after primary vaccination among normal and high-responder adults, while the positive rate of anti-HBs still kept at a high level. The anti-HBs persistence after primary vaccination was associated with HepB type, age and GMC of anti-HBs one month after vaccination.

[Antibody persistence following primary vaccination with hepatitis B vaccine among normal and high-responder adults: a 5-year follow-up study].

OBJECTIVE: To evaluate the 5-year antibody persistence and the risk factors associated with the persistence after primary vaccination of hepatitis B vaccine (HepB) among normal or high-response adults. METHODS: A total of 24 237 healthy adults who had no histories of hepatitis B infection and hepatitis B vaccination, resided in the local area for more than six months and were aged 18-49 years were selected from 79 villages in north of Zhangqiu county, Shandong province, China in 2009. Blood samples were obtained and hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected using ELISA method. A total of 11 590 persons who were negative for all of these indicators were divided into four groups by cluster sampling methods. Each group was vaccinated with one of the following four types of HepB at 0-1-6 months schedule: 20 µg HepB derived in Saccharomyces cerevisiae (HepB-SC), 20 µg HepB derived in Chinese hamster ovary cell (HepB-CHO), 10 µg HepB-SC and 10 µg HepB derived in Hansenula polymorpha (HepB-HP). The normal and high-responder was followed up and their demographic characteristic (including age, gender), histories of hepatitis B infection, hepatitis B vaccination, smoking, drinking and chronic diseases were investigated. Blood samples were collected one month (T1) and five years (T2) and anti-HBs, anti-HBc and HBsAg (if anti-HBs<10 mU/ml) were detected by CMIA. A total of 1 902 participants were followed up and the risk factors associated with positive rate of anti-HBs and GMC of anti-HBs were identified by multiple logistic regression analysis and multifactor linear regression model analysis, respectively. RESULTS: Among 1 902 adults, 824 (43.32%) were male and 1 078 (56.68%) were female. The anti-HBs positive rate was 100% at T1 and it decreased to 73.29% (1 394 cases) at T2. The corresponding GMC was decreased from 1 527.15 (95%CI: 1 437.84-1 622.01) mU/ml at T1 to 35.07 (95%CI: 32.20-38.19) mU/ml at T2. When comparing with those vaccinated 20 µg HepB-SC, the significantly lower positive rate at T2 was observed in those vaccinated 10 µg HepB-SC group and 10 µg HepB-HP group. The OR (95% CI) was 0.41 (0.28-0.61) and 0.27 (0.18-0.39), respectively. The GMC of anti-HBs was also significantly lower among those vaccinated 10 µg HepB-SC and 10 µg HepB-HP. The b (95%CI) was -0.20 (-0.28- -0.12) and -0.36 (-0.44- -0.29) , respectively. When comparing with those occasionally drinking, the significantly lower positive rate at T2 was observed in those regular drinking. The OR(95%CI) was 0.51(0.30-0.87). The GMC of anti-HBs in age group of 18-29 was significantly higher than those in 40-49 age group; the b (95%CI) was -0.10(-0.18- -0.01). When comparing with those whose anti-HBs titer was less than 999 mU/ml at T1, the significantly higher positive rate of anti-HBs at T2 was observed in those whose anti-HBs titer was 1 000-1 999 mU/ml, those whose anti-HBs titer was 2 000-2 999 mU/ml and those whose anti-HBs titer was ≥10 000 mU/ml. The OR (95%CI) was 10.11 (6.90-14.82), 20.42 (13.98-29.82) and 54.58 (22.08-134.92), respectively. When comparing with those whose anti-HBs titer was ≤999 mU/ml at T1, the GMC of anti-HBs at T2 was also significantly higher among those whose anti-HBs titer at T1 was 1 000-1 999 mU/ml, those whose anti-HBs titer at T1 was 2 000-2 999 mU/ml and those whose anti-HBs titer at T1 was ≥10 000 mU/ml. The b (95%CI) was 0.55 (0.47-0.62), 0.94 (0.88-1.00) and 1.63 (1.54-1.72), respectively. Nobody was found positive to HBsAg at T2 and the conversion rate of anti-HBc was 3.89% (74/1 902) at T2. CONCLUSION: Anti-HBs GMC decreased rapidly at T2 among normal and high-responder adults, while the positive rate of anti-HBs still kept at a high level. The antibody persistence among normal and high-responder adults at T2 was associated with HepB type, age, history of drinking and GMC of anti-HBs at T1.

[Anti-HBs persistence following revaccination with three doses of hepatitis B vaccine among low-responsive adults after primary vaccination: a 4-year follow-up study].

OBJECTIVE: To assess the 4-year anti-HBs persistence after revaccination with 3-dose of hepatitis B vaccine (HepB) among low-responsive adults. METHODS: A total of 24 237 healthy adults who had no history of hepatitis B infection and hepatitis B vaccination, resided in the local area for more than six months and were aged 18-49 years were selected from 79 villages of Zhangqiu county, Shandong province, China in 2009. Blood samples were obtained and hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected using ELISA method. A total of 11 590 persons who were negative for all of these indicators were divided into four groups by cluster sampling method. Each group was vaccinated with one of the following four types of HepB at 0-1-6 months schedule: 20 µg HepB derived in Saccharomyces cerevisiae (HepB-SC), 20 µg HepB derived in Chinese hamster ovary cell (HepB-CHO), 10 µg HepB-SC and 10 µg HepB derived in Hansenula polymorpha (HepB-HP). Blood samples were collected one month after the third dose of primary immunization and tested for anti-HBs using chemiluminescence microparticle immunoassay (CMIA). The 892 low-responders were revaccinated with three doses of HepB at 0-1-6 months schedule and the type of HepB was the same as which was used for primary immunization. During the follow-up to low-responders, the following informations were collected: the demographic characteristics (including age, gender), histories of hepatitis B infection, hepatitis B vaccination, smoking, drinking and chronic diseases. Blood samples were collected one month (T1) and four years after revaccination and anti-HBs, anti-HBc and HBsAg (if anti-HBs <10 mU/ml) were detected by CMIA. The risk factors associated with positive rate of anti-HBs and GMC of anti-HBs were identified by multiple logistic regression analysis and multifactor linear regression model analysis respectively. Anti-HBs titer at T1 was grouped according to the level and was considered as the independent variable in the model analysis. RESULTS: A total of 529 participants were identified from 892 low-responders. Among 529 participants, 276 (52.2%) were males and 253 (47.8%) were females. The positive rate was 82.6% (437/529) at T1 and it decreased to 28.2% (149/529) four years after revaccination. The corresponding GMC decreased from 542.06 (95% CI: 466.72-629.56) mU/ml to 27.69 (95% CI: 23.08-33.23) mU/ml. Multivariable analysis showed the positive rate of anti-HBs 4 years after revaccination was independently associated with anti-HBs titer at T1. The positive rate among those whose anti-HBs titer more than 1 000 mU/ml at T1 was significantly higher than those whose anti-HBs titer less than 100 mU/ml. The OR (95%CI) was 39.67 (13.81-114.01). The GMC was associated with HepB type for revaccination and anti-HBs titer at T1. The GMC among those revaccinated 20 µg HepB was significantly higher than those revaccinated 20 µg HepB-CHO, 10 µg HepB-SC and 10 µg HepB-HP. The b (95% CI) was -0.40 (-0.78--0.02), -0.57 (-1.01- -0.15) and -0.63 (-1.03- -0.23), respectively. The GMC among those whose anti-HBs titer 100-999 mU/ml and those whose anti-HBs titer ≥1 000 mU/ml at T1 were higher than those whose anti-HBs titer <100 mU/ml. The b (95% CI) was 0.93 (0.53-1.33) and 3.31 (2.88-3.73) respectively. CONCLUSION: Anti-HBs GMC decreased rapidly 4 years after revaccination among low-responsive adults, but still kept good protecion. The anti-HBs persistence after revaccination was associated with HepB type for revaccination and anti-HBs level of titer one month after revaccination.

[Anti-HBs persistence after revaccination with three doses of hepatitis B vaccine among non-responsive adults: a 4-year of follow-up study].

OBJECTIVE: To explore anti-HBs persistence four years after revaccination with hepatitis B vaccine (HepB) among adults who were non-responsive to HepB primary immunization. METHODS: A total of 24 237 healthy adults who had no history of hepatitis B infection and hepatitis B vaccination, resided in the local area for more than six months and aged 18-49 years were selected from 79 villages of Zhangqiu County, Shandong Province, China in 2009. Blood samples were obtained and hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected using ELISA method. A total of 11 590 persons who were negative for all of these indicators were divided into four groups by cluster sampling methods. Each group was vaccinated with one of the following four types of HepB at 0-1-6months schedule: 20 µg HepB derived in Saccharomyces cerevisiae (HepB-SC), 20 µg HepB derived in Chinese hamster ovary cell (HepB-CHO), 10 µg HepB-SC and 10 µg HepB derived in Hansenula polymorpha (HepB-HP). Blood samples were collected one month after the third dose of primary immunization and tested for anti-HBs using chemiluminescence microparticle immunoassay (CMIA). The non-responders were followed up and their basic information and the histories of hepatitis B infection, HepB vaccination, smoking and drinking were investigated. Then they were revaccinated with three doses of HepB with the same schedule as the primary immunization. Blood samples were collected from all of them one month (T1), two years and four years after revaccination and anti-HBs, anti-HBc and HBsAg were detected by CMIA. A total of 356 participants were followed up from 645 low-responders four years after revaccination, and the ratio was 55.2%. The risk factors associated with the positive rate and geometric mean concentration (GMC) of anti-HBs after four years of revaccination were analyzed using multivariate unconditional logistic regression model and multivariate linear regression model, respectively. RESULTS: Among 356 participants, 172 (48.3%) were males and 184 (51.7%) were females. The anti-HBs positive rate was 90.4% (322 cases) at T1 and was 55.9% (199 cases) four years after revaccination. The GMC of anti-HBs was 240.5 (95% CI: 186.4-310.4)mU/ml at T1 and decreased to 15.0 (95%CI: 12.2-18.5) mU/ml four years after revaccination. The average annual decreasing rate of GMC was 50.63% from one month after revaccination to four years after revaccination. The corresponding rate was 64.89% in the first two years, which was 2.12 times the rate in the latter two years (30.57%). When compared with those whose anti-HBs titer was less than 99 mU/ml at T1, the significantly higher anti-HBs four years after revaccination was observed in those whose anti-HBs titer at T1 was 100-999 mU/ml and those whose anti-HBs titer at T1 was ≥1 000 mU/ml. The OR (95%CI) was 7.14 (3.90-13.05) and 28.40 (13.16-61.30) respectively. When compared with those whose anti-HBs titer was ≤99 mU/ml at T1, the GMC of anti-HBs four years after revaccination was also significantly higher among those whose anti-HBs titer at T1 was 100-999 mU/ml and those whose anti-HBs titer at T1 was ≥1 000 mU/ml. The b (95%CI) was 1.66 (1.26-2.05) and 3.16 (2.72-3.60), respectively. CONCLUSION: The positive rate and GMC of anti-HBs decreased four years after revaccination among non-responsive adults, but still kept anti-HBs above protective level. The immunity durability after revaccination is mainly associated with anti-HBs titer one month after revaccination.

[Rates and characteristics for hepatitis B reactivation of inactive hepatitis B carriers in rural communities].

Objective: To analyze the intensity and epidemiological characteristics of hepatitis B virus (HBV) reactivation among inactive HBsAg carriers (IHC) of rural areas in Ji'nan. Methods: In 2018 and 2020, follow-up investigations were conducted on IHC identified in the population physical examination in Zhangqiu district of Ji'nan. The results of the two follow-up visits were compared to analyze the incidence and distribution characteristics of HBV reactivation in IHC at the community level. Results: A total of 424 IHC completed two follow-up visits, and 47 cases of HBV reactivation were found, the cumulative reactivation rate was 11.08%, and the incidence density was 5.46/100 person-years. Multivariate analysis showed that gender, age, smoking, drinking , family history of liver disease and chronic diseases were not associated with HBV reactivation (P>0.05), and baseline HBV DNA load was associated with reactivation (P<0.05), in the HBV DNA level ≥1 000 IU/ml group, the reactivation rate could reach 18.92%. After reactivation, the mean level of ALT increased from baseline and the abnormal rate increased, liver function tended to be abnormal in reactivated patients. 4 (8.51%) reactivators had hepatitis, and 1 (2.13%) had jaundice hepatitis. Conclusions: The incidence of HBV reactivation was higher among IHC in rural communities in Ji'nan. Most of the reactivators were asymptomatic or mildly reactivated. Follow-up of inactive HBsAg patients should be strengthened and changes in ALT and HBV DNA levels should be closely monitored.

[Antibodies persistence after revaccination with three doses of hepatitis B vaccine in non-responsive adults: results from 8-year follow-up study].

Objective: To evaluate the persistence of HBsAg-specific antibodies eight years after revaccination with hepatitis B vaccine (HepB) among adults who were non-responsive to primary immunization. Methods: From August to September 2009, rural communities in Zhangqiu district of Ji'nan city were selected as the study site. The subject's inclusion criteria were 18 to 49 years old, local resident population, without HBV infection history and HepB vaccination history, and good health status. Antibodies against hepatitis B surface antigen (anti-HBs) were detected in adults following the standard primary vaccination. Those who were non-responders (anti-HBs titer <10 mIU/ml) were revaccinated with three doses of HepB and included in the study. Blood samples were collected from all of them at one month (T1), two years, four years, and eight years after revaccination. The three indexes of anti-HBs, hepatitis B surface antigen (HBsAg), together with antibody against hepatitis B core antigen (anti-HBc), were measured by chemiluminescence microparticle immunoassay (CMIA). Results: The proportion of subjects with anti-HBs titers ≥10 mIU/ml was 85.12% (549/645) at T1, 60.60% (283/467) at two years, 55.90% (199/356) at four years and 55.09% (222/403) at eight years after revaccination. The first two years' annual decline rates, three to four years and five to eight years, were 15.62%, 3.96%, and 0.36%. The GMC of anti-HBs was 153.92 mIU/ml at T1, 21.43 mIU/ml at two years, 15.02 mIU/ml at four years, and 13.68 mIU/ml at eight years. In the first two years, three to four years and five to eight years, the annual decline rate of GMC was 62.69%,16.28%, and 2.31%, respectively. Multivariable analysis showed that the titer of anti-HBs at T1 was independently associated with the persistence of anti-HBs at eight years after revaccination. Compared with anti-HBs titer <100 mIU/ml , those whose anti-HBs titers were 100-mIU/ml and ≥1 000 mIU/ml at T1 had a higher positive rate of anti-HBs (OR=14.13, P<0.001; OR= 62.91, P<0.001) and a higher probability of anti-HBs titer (ß=1.88, P<0.001; ß=3.24, P<0.001) at 8 years after revaccination. Nobody was found seroconversion of HBsAg, and the anti-HBc positive rate was 14.14% (57/403). Conclusions: Following revaccination with three doses of HepB in adults who were non-responsive to primary immunization, anti-HBs titers declined rapidly within the first four years. They then maintained a stable level after the fifth year. More than half still kept anti-HBs protective titer at eight years after revaccination. The immunity persistence was associated with anti-HBs titer at one month after revaccination.