Molecular Epidemiology of Herpangina Children in Tongzhou District, Beijing, China, During 2019-2020.

Background: The changing pattern of pathogen spectrum causing herpangina in the time of coronavirus disease 2019 (COVID-19) pandemic was unknown. The purpose of this study was to investigate the changes on the molecular epidemiology of herpangina children during 2019-2020 in Tongzhou district, Beijing, China. Method: From January 2019 to December 2020, children diagnosed with herpangina were recruited by the staff from Tongzhou Center for Disease Control and Prevention (CDC) in Beijing. Viral RNA extraction from pharyngeal swabs was used for enterovirus (EV) detection and the complete VP1 gene was sequenced. The phylogenetic analysis was performed based on all VP1 sequences for EV genotypes. Result: A total of 1,331 herpangina children were identified during 2019-2020 with 1,121 in 2019 and 210 in 2020, respectively. The predominant epidemic peak of herpangina children was in summer and autumn of 2019, but not observed in 2020. Compared to the number of herpangina children reported in 2019, it decreased sharply in 2020. Among 129 samples tested in 2019, 61 (47.3%) children were detected with EV, while 22.5% (20/89) were positive in 2020. The positive rate for EV increased since June 2019, peaked at August 2019, and decreased continuously until February 2020. No cases were observed from February to July in 2020, and the positive rate of EV rebounded to previous level since August 2020. Four genotypes, including coxsackievirus A6 (CV-A6, 9.3%), CV-A4 (7.8%), CV-A10 (2.3%) and CV-A16 (10.1%), were identified in 2019, and only three genotypes, including CV-A6 (9.0%), CV-A10 (6.7%) and CV-A16 (1.1%), were identified in 2020. The phylogenetic analysis showed that all CV-A6 strains from Tongzhou located in Group C, and the predominant strains mainly located in C2-C4 subgroups during 2016-2018 and changed into C1 subgroup during 2018-2020. CV-A16 strains mainly located in Group B, which consisting of strains widely distributed around the world. Conclusions: The predominant genotypes gradually shifted from CV-A16, CV-A4 and CV-A6 in 2019 to CV-A6 in 2020 under COVID-19 pandemic. Genotype-based surveillance will provide robust evidence and facilitate the development of public health measures.

First line nucleos(t)ide analog monotherapy is more cost-effective than combination strategies in hepatitis B e antigen-positive chronic hepatitis B patients in China.

BACKGROUND: Nucleos(t)ide analog (NA) in combination with peginterferon (PegIFN) therapy in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) shows better effectiveness than NA monotherapy in hepatitis B surface antigen loss, termed "functional cure," based on previous published studies. However, it is not known which strategy is more cost-effective on functional cure. The aim of this study was to analyze the cost-effectiveness of first-line monotherapies and combination strategies in HBeAg-positive CHB patients in China from a social perspective. METHODS: A Markov model was developed with functional cure and other five states including CHB, compensated cirrhosis, decompensated cirrhosis, hepatocellular carcinoma, and death to assess the cost-effectiveness of seven representative treatment strategies. Entecavir (ETV) monotherapy and tenofovir disoproxil fumarate (TDF) monotherapy served as comparators, respectively. RESULTS: In the two base-case analysis, compared with ETV, ETV generated the highest costs with $44,210 and the highest quality-adjusted life-years (QALYs) with 16.78 years. Compared with TDF, treating CHB patients with ETV and NA - PegIFN strategies increased costs by $7639 and $6129, respectively, gaining incremental QALYs by 2.20 years and 1.66 years, respectively. The incremental cost-effectiveness ratios were $3472/QALY and $3692/QALY, respectively, which were less than one-time gross domestic product per capita. One-way sensitivity analysis and probabilistic sensitivity analyses showed the robustness of the results. CONCLUSION: Among seven treatment strategies, first-line NA monotherapy may be more cost-effective than combination strategies in HBeAg-positive CHB patients in China.

Implementing the communication for development strategy to improve knowledge and coverage of measles vaccination in western Chinese immunization programs: a before-and-after evaluation.

BACKGROUND: Communication for Development (C4D) is a strategy promoted by the United Nations Children's Fund to foster positive and measurable changes at the individual, family, community, social, and policy levels of society. In western China, C4D activities have previously been conducted as part of province-level immunization programs. In this study, we evaluated the association of C4D with changes in parental knowledge of immunization services, measles disease, and measles vaccine, and changes in their children's measles vaccine coverage. METHODS: From April 2013 to April 2014, C4D activities were implemented as part of provincial immunization programs in the Inner Mongolia, Guangxi, Chongqing, Guizhou, Tibet, Shaanxi, Gansu, Ningxia, and Qinghai provinces. We used a before-and-after study design and employed face-to-face interviews to assess changes in parental knowledge and vaccination coverage. RESULTS: We surveyed 2 107 households at baseline and 2 070 households after 1 year of C4D activities. Following C4D, 95% of caregivers were aware of the vaccination record check requirement for entry into kindergarten and primary school; 80% of caregivers were aware that migrant children were eligible for free vaccination; more than 70% of caregivers knew that measles is a respiratory infectious disease; and 90% of caregivers knew the symptoms of measles. Caregivers' willingness to take their children to the clinic for vaccination increased from 51.3% at baseline to 67.4% in the post-C4D survey. Coverage of one-dose measles-containing vaccine (MCV) increased from 83.8% at baseline to 90.1% after C4D. One-dose MCV coverage was greater than 95% in the Guangxi, Shaanxi, and Gansu provinces. Two-dose MCV coverage increased from 68.5 to 77.6%. House-to-house communication was the most popular C4D activity among caregivers (91.6% favoring), followed by posters and educational talks (64.8 and 49.9% favoring). CONCLUSIONS: C4D is associated with increased caregiver knowledge about measles, increased willingness to seek immunization services for their children, and increased measles vaccination coverage. Tailored communication strategies based on insights gained from these analyses may be able to increase vaccination coverage in hard-to-reach areas. C4D should be considered for larger scale implementation in China.

Hepatitis B Immunoprophylactic Failure and Characteristics of the Hepatitis B Virus Gene in Mother-Infant Pairs in Parts of China.

OBJECTIVE: To determine the hepatitis B immunoprophylactic failure rate in infants born to hepatitis B virus (HBV) infected mothers and to characterize HBV genes. METHODS: HBV-serological testing was conducted for pregnant women and infants. The complete genomes of 30 HBV isolates were sequenced, and genetic characteristics were analyzed using MEGA 5 software. RESULTS: The immunoprophylactic failure rate for infants who had completed the scheduled hepatitis B vaccination program was 5.76% (32/556). High sequence homology (99.8%-100%) was observed in 8 of the 10 mother-infant pairs. We identified 19 subgenotype C2 strains, 9 subgenotype B2 strains, and 2 subgenotype C1 strains. Three serotypes were detected: adr (19/30), adw (9/30), and ayw (2/30). The frequency of amino acid mutation of the 'a' determinant region was 16.67% (5/30), including that of Q129H, F134Y, S136Y, and G145E. We detected 67 amino acid mutations in the basal core promoter, precore, and core regions of the genome. CONCLUSION: The immunoprophylactic failure rate in infants born to HBV-infected mothers is low in the regions of China examined during this study. Moreover, HBV mutation in the 'a' determinant region could not account for immunoprophylactic failure for all infants.

The Public Health Burden of Rotavirus Disease in Children Younger Than Five Years and Considerations for Rotavirus Vaccine Introduction in China.

BACKGROUND: Rotavirus is the leading cause of severe diarrhea among young children worldwide. Rotavirus vaccines have demonstrated substantial benefits in many countries that have introduced vaccine nationally. In China, where rotavirus vaccines are not available through the national immunization program, it will be important to review relevant local and global information to determine the potential value of national introduction. Therefore, we reviewed evidence of rotavirus disease burden among Chinese children younger than 5 years to help inform rotavirus vaccine introduction decisions. METHODS: We reviewed scientific literature on rotavirus disease burden in China from 1994 through 2014 in China National Knowledge Infrastructure, Wanfang and PubMed. Studies were selected if they were conducted for periods of 12 month increments, had more than 100 patients enrolled and used an accepted diagnostic test. RESULTS: Overall, 45 reports were included and indicate that rotavirus causes ~40% and ~30% of diarrhea-related hospitalizations and outpatient visits, respectively, among children younger than 5 years in China. Over 50% of rotavirus-related hospitalizations occur by age 1 year; ~90% occur by age 2 years. Regarding circulating rotavirus strains in China, there has been natural, temporal variation, but the predominant local strains are the same as those that are globally dominant. CONCLUSIONS: These findings affirm that rotavirus is a major cause of childhood diarrheal disease in China and suggest that a vaccination program with doses given early in infancy has the potential to prevent the majority of the burden of severe rotavirus disease.

An economic analysis of adult hepatitis B vaccination in China.

BACKGROUND AND OBJECTIVE: With the universal infant hepatitis B vaccination (HepB) program, China has made remarkable achievements to prevent and control hepatitis B. In order to further reduce hepatitis B virus (HBV) infection, the Chinese government is considering implementing a widespread adult HBV vaccination campaign. We performed an economic analysis of two different adult HepB vaccination strategies for 21-59-years-olds: vaccination without screening and screening-based vaccination. METHODS: Cost-benefit analyses were conducted. All 21-59-year-olds were divided into two groups: young adults (ages 21-39) and middle-aged adults (ages 40-59). Costs and benefits were estimated using the direct cost and societal (direct and indirect costs) perspectives. All costs and benefits were adjusted to 2014 US dollars, where future values were discounted at a 3% annual rate. We calculated benefit-cost ratios (BCRs) of the two vaccination strategies for the two different age groups. Sensitivity analyses varied key parameters within plausible ranges. RESULTS: Among young adults, the direct and societal BCRs for a vaccination campaign with no screening would be 1.06 and 1.42; with a screening-based vaccination campaign, the model estimated the direct and societal BCRs would be 1.19 and 1.73. Among middle-aged adults, the direct and societal BCRs for a vaccination campaign without screening would be 0.59 and 0.59; with a screening-based vaccination campaign, the model estimated the direct and societal BCRs would be 0.68 and 0.73. CONCLUSION: The results of our study support a HepB vaccination campaign for young adults. Additionally, a vaccination campaign with screening appeared to provide greater value than a vaccination without screening.

An outbreak following importation of wild poliovirus in Xinjiang Uyghur Autonomous Region, China, 2011.

BACKGROUND: After more than 10 years without a case of wild poliovirus (WPV) in China, an outbreak occurred in 2011 in Xinjiang Uyghur Autonomous Region. METHODS: Acute flaccid paralysis (AFP) case surveillance was strengthened with epidemiological investigations and specimen collection and serological surveys were conducted among hospitalized patients. RESULTS: There were 21 WPV cases and 23 clinical compatible polio cases reported. WPV was isolated from 14 contacts of AFP cases and 13 in the healthy population. Incidence of WPV and clinical compatible polio cases were both highest among children <1 years, however, 24/44 (54.5%) polio cases were reported among adults aged 15-39 years. CONCLUSIONS: High coverage of routine immunization should be maintained among children until WPV transmission is globally eradicated. Expansion of AFP case surveillance and use of serologic surveys to estimate population immunity should be conducted rapidly to guide preparedness and response planning for future WPV outbreaks.

Enhanced surveillance of acute flaccid paralysis following importation of wild poliovirus in Xinjiang Uygur Autonomous Region, China.

BACKGROUND: After being polio free for more than 10 years, an outbreak occurred in China in 2011 in Xinjiang Uygur Autonomous Region (Xinjiang) following the importation of wild poliovirus (WPV) originating from neighboring Pakistan. METHODS: To strengthen acute flaccid paralysis (AFP) surveillance in Xinjiang, "zero case daily reporting" and retrospective searching of AFP cases were initiated after the confirmation of the WPV outbreak. To pinpoint all the polio cases in time, AFP surveillance system was expanded to include persons of all ages in the entire population in Xinjiang. RESULTS: Totally, 578 AFP cases were reported in 2011 in Xinjiang, including 21 WPV cases, 23 clinical compatible polio cases and 534 non-polio AFP cases. Of the 44 polio cases, 27 (61.4%) cases were reported among adults aged 15-53 years. Strengthening AFP surveillance resulted in an increase in the number of non-polio AFP cases in 2011 (148 children < 15 years) compared with 76 cases < 15 years in 2010. The AFP surveillance system in Xinjiang was sensitive enough to detect polio cases, with the AFP incidence of 3.28/100,000 among children < 15 years of age. CONCLUSIONS: Incorporating adult cases into the AFP surveillance system is of potential value to understand the overall characteristics of the epidemic and to guide emergency responses, especially in countries facing WPV outbreak following long-term polio free status. The AFP surveillance system in Xinjiang was satisfactory despite limitations in biological sample collection.

Identification and control of a poliomyelitis outbreak in Xinjiang, China.

BACKGROUND: The last case of infection with wild-type poliovirus indigenous to China was reported in 1994, and China was certified as a poliomyelitis-free region in 2000. In 2011, an outbreak of infection with imported wild-type poliovirus occurred in the province of Xinjiang. METHODS: We conducted an investigation to guide the response to the outbreak, performed sequence analysis of the poliovirus type 1 capsid protein VP1 to determine the source, and carried out serologic and coverage surveys to assess the risk of viral propagation. Surveillance for acute flaccid paralysis was intensified to enhance case ascertainment. RESULTS: Between July 3 and October 9, 2011, investigators identified 21 cases of infection with wild-type poliovirus and 23 clinically compatible cases in southern Xinjiang. Wild-type poliovirus type 1 was isolated from 14 of 673 contacts of patients with acute flaccid paralysis (2.1%) and from 13 of 491 healthy persons who were not in contact with affected persons (2.6%). Sequence analysis implicated an imported wild-type poliovirus that originated in Pakistan as the cause of the outbreak. A public health emergency was declared in Xinjiang after the outbreak was confirmed. Surveillance for acute flaccid paralysis was enhanced, with daily reporting from all public and private hospitals. Five rounds of vaccination with live, attenuated oral poliovirus vaccine (OPV) were conducted among children and adults, and 43 million doses of OPV were administered. Trivalent OPV was used in three rounds, and monovalent OPV type 1 was used in two rounds. The outbreak was stopped 1.5 months after laboratory confirmation of the index case. CONCLUSIONS: The 2011 outbreak in China showed that poliomyelitis-free countries remain at risk for outbreaks while the poliovirus circulates anywhere in the world. Global eradication of poliomyelitis will benefit all countries, even those that are currently free of poliomyelitis.

[Study on the risk of HBV infection among spouses of HBsAg carriers].

OBJECTIVE: To investigate the risk of HBV infection among the spouses of hepatitis B virus surface antigen (HBsAg) carriers and to provide a reference for developing strategies on hepatitis B control and prevention. METHODS: A case-control study including HBsAg carriers aged 20 - 45 years-old from the nationwide sero-epidemiological survey for Hepatitis B in both Guangdong and Jiangxi provinces in 2006, together with their spouses were selected as case group, while. HBsAg negative persons and their spouses were among the control groups, under the same residential areas, gender, age and age of marriage to the HBsAg carriers. Questionnaire survey and hepatitis B serological markers detection were carried out, together with the HBV genotype detection among the HBsAg positive couples between husband and wife by PCR. RESULTS: Among the spouses of HBsAg carriers, the positive rate of HBsAg was 13.21%, while the rate was 6.29% for the spouse of HBsAg negative population, with difference statistically significant (χ² = 4.23, P < 0.05). HBsAg positive rate among spouses of the case group was higher than that in the control group. Among the spouses of HBsAg carriers, the HBsAg rate was positively correlated with the age of marriage, frequency of sexual intercourse and condom use. There were 21 pairs of HBsAg carriers between husband and wife, and HBV were isolated among 13 pairs, and there were 11 pairs carrying the same HBV genotype, accounting for 84.62%. HBV genotypes would include 8 pairs of type B and 3 pairs of type C. However, only 2 pairs were infected with different HBV genotype. CONCLUSION: High risks of HBV infection existed in the spouses of HBsAg carriers. It was important to ask the HBsAg carriers to take the initiative in informing their spouses, and carrying out the appropriate measures, such as safe sex or timely hepatitis B vaccination for the spouse of HBsAg carriers etc., so as to reduce the HBV transmission between husband and wife.

[Study on antibody response to revaccination of hepatitis B vaccine among firstly low-response adults].

OBJECTIVE: To evaluate and compare the antibody to hepatitis B virus (HBV) surface antigen (anti-HBs) response and the influent factors of revaccination of 4 kinds of hepatitis B vaccine (HepB) among firstly low-response adults. METHODS: A total of 11 590 adults who were 18 - 49 years old, never received HepB vaccination, without HBV infection history, HBs-Ag negative, and had been living at 3 towns of Zhangqiu county in Shandong province Ji'nan city for more than half a year, were selected in the study in July, 2009. Self-designed questionnaire was used to select the basic information of the subjects. The subjects were divided into 4 groups by cluster sampling, and were vaccinated according to the "0-1-6" immune procedure with 10 µg HepB made by recombinant deoxyribonucleic acid techniques in Saccharomyces Cerevisiae (HepB-SC), 10 µg HepB made by recombinant deoxyribonucleic acid techniques in Hansenula Polymorpha (HepB-HP), 20 µg HepB-SC and 20 µg HepB made by recombinant deoxyribonucleic acid techniques in Chinese hamster ovary cell (HepB-CHO), 3 doses respectively. The adults who were low-response to the primary hepatitis B vaccination (10 mU/ml ≤ anti-HBs < 100 mU/ml) were divided into four groups by cluster sampling. These groups were revaccinated with one-dose of above-mentioned four kinds of HepB respectively. Blood samples were drawn from each person one month after the revaccination. Anti-HBs was detected by chemiluminescence microparticle immunoassay and compared by the vaccine type. The influence factors about antibody response were also analyzed. RESULTS: Out of the 11 590 subjects, 8592 adults had accepted the primary vaccination of hepatitis B and been collected the blood samples; among whom, 1306 subjects showed low-response, at the rate of 15.20%. A total of 1034 low-response subjects accepted secondary strengthened vaccination and were collected blood samples; 55.13% of them showed anti-HBs seroconversion (anti-HBs ≥ 100 mU/ml); while the seroconversion rate in each group was 44.54% (106/238) in 10 µg HepB-SC group, 57.14% (156/273) in 10 µg HepB-HP group, 56.08% (143/255) in 20 µg HepB-SC group and 61.57% (165/268) in 20 µg HepB-CHO group, respectively. There was significant difference among the groups (χ² = 17.14, P < 0.01). The rates of anti-HBs seroconversion were significantly higher in 10 µg HepB-HP and 20 µg HepB-CHO groups than it in 10 µg HepB-SC group (χ² were 8.09 and 14.70 respectively, P < 0.01). The geometric mean concentration (GMC) of anti-HBs was 178.24 mU/ml among the low-responders after one dose of revaccination. The GMC was 109.77, 243.50, 144.98 and 242.83 mU/ml in 10 µg HepB-SC group, 10 µg HepB-HP group, 20 µg HepB-SC group and 20 µg HepB-CHO group, respectively. There was significant difference among groups (F = 9.52, P < 0.01). CONCLUSION: Anti-HBs response could be strengthened effectively after one-dose of HepB revaccination among the low-response adults. Many factors like the vaccine types could effect the immune effects to HepB. A better response could be achieved if the 20 µg HepB-CHO or 10 µg HepB-HP was used for revaccination.

[Comparison on the antibody response after primary immunization of 5 µg and 10 µg hepatitis B vaccine made by recombinant DNA techniques among newborns].

OBJECTIVE: To compare the antibody response induced by primary immunization with 5 µg and 10 µg hepatitis B vaccine made by recombinant DNA techniques among the newborns. METHODS: Healthy infants who had completed primary immunization with 5 µg hepatitis B vaccine made by recombinant dexyribonucleic acid techniques in Saccharomyces (Hep-SC) or 10 µg hepatitis B vaccine made by recombinant dexyribonucleic acid techniques in Hansenula polymorpha (HepB-HP) were included in the study. Kids under study were 7-12 months of age and had been on 0-1-6 schedule. Standardized questionnaire was used and blood samples were collected. The titer of antibody to hepatitis B surface antigen (anti-HBs) was detected by Chemiluminescence Microparticle Imunoassay (CMIA). If anti-HBs happened to be under 10 mIU/ml, HBV DNA was further detected by nested-PCR to distinguish occult hepatitis B virus infection. Sero-conversion rate and titer of anti-HBs were compared between the two kinds of hepatitis B vaccines. Multivariate analysis was used to find the relationship between the kind of hepatitis B vaccine as well as the antibody response after debugging the other influencing factors including month-age, gender, birth-weight, premature birth and mother's HBsAg status. RESULTS: 8947 infants vaccinated with 5 µg HepB-SC and 4576 infants vaccinated with 10 µg HepB-HP were investigated. In the 5 µg group, the rates of non-, low-, normal- and high-response were 1.88%, 15.18%, 61.42% and 21.52% respectively. In the 10 µg group, the corresponding rates were 0.15%, 2.16%, 29.42% and 68.26% respectively. The non-, low-, normal-response rates were all higher in 5 µg group than in 10 µg group (P<0.01), while the high-response rate was much higher in 10 µg group than in 5 µg group (P<0.01). The geometric mean concentration (GMC) of anti-HBs were 354.81 mIU/ml (95%CI: 338.84-363.08 mIU/ml) and 1778.28 mIU/ml (95%CI: 1698.24-1819.70 mIU/ml) in the 5 µg group and 10 µg group respectively. The GMC was statistically higher in the 10 µg group than in the 5 µg group (P<0.001). The sero-conversion rate and GMC were significantly different between the two groups even after debugging the other influencing factors. CONCLUSION: Better anti-HBs response could be achieved by primary immunization with 10 µg HepB-HP than with 5 µg HepB-SC among newborns.

[Multi-center matching study on antibody response between preterm and full-term infants after primary immunization of hepatitis B vaccine].

OBJECTIVE: To compare the antibody response between preterm and full-term infants after primary immunization of hepatitis B vaccine (HepB). METHODS: Infants who were aged 7 - 12 months and had completed primary immunization with 5 µg HepB made by recombinant deoxyribonucleic acid techniques in saccharomyces cerevisiae (HepB-SC) or 10 µg HepB made by recombinant deoxyribonucleic acid techniques in Hansenula polymorpha (HepB-HP) on 0-1-6 schedule were investigated in four provinces (municipality) including Beijing, Shandong, Jiangsu and Guangxi of China. Among them, all preterm infants were selected to form the preterm group and the 1:1 matching full-term infants with the same month-age, gender and residence were randomly selected to form the full-term group. Their HepB history was determined by immunization certificate and all of their parents were interviewed with standard questionnaire to get their birth information. Blood samples were obtained from all anticipants and were tested for Anti-HBs by chemiluminescence microparticle immuno-assay (CMIA). RESULTS: Total anticipants were 648 pairs of infants. The rates of non-response, low-response, normal-response and high-response after the primary immunization were 1.39%, 8.64%, 45.83% and 44.14% in the preterm group, respectively. The corresponding rates were 1.08%, 9.26%, 44.91% and 44.75% in the full-term group. The above four rates did not show significant differences between the two groups (P > 0.05). The geometric mean concentrations (GMC) of anti-HBs in the pre-term and full-term group were 755.14 and 799.47 mIU/ml respectively. There was no significantly difference in the GMCs between the two groups (P > 0.05). Results from multivariable conditional logistic analysis showed that preterm was not an influencing factor to the antibody response after HepB primary immunization among newborns even after debugging the other influencing factors. CONCLUSION: The antibody response after HepB primary immunization were similar among the preterm and full-term infants. The preterm newborns could be immunized under the same HepB immunization strategy.

[Estimation on the intangible cost and influencing factors for patients with hepatitis B-related diseases].

OBJECTIVE: To estimate the intangible cost and associated factors on patients with hepatitis B-related diseases, so as to explore the differences of the three elicitation techniques on the 'willingness to pay approach' (WTP). METHODS: Face-to-Face interviews were conducted to collect health economics-related information by trained investigators, using a structured questionnaire. WTP was employed to estimate the intangible cost while an open-ended question format, together with iterative bidding game and payment card were respectively used to elicit WTP for the hypothetical cure of hepatitis B-related diseases. A Multiple linear stepwise regression model was determined to identify those factors potentially affecting the intangible cost. RESULTS: A total of 564 subjects from 641 patients with hepatitis B-related diseases were identified for the inclusion of this study. The average annual intangible cost of patient with hepatitis B-related diseases was 54 320.4 Yuan (Ren Minbi). The intangible cost accounted for 53.0% of the total cost, which was much more than the proportions of the direct and indirect costs (38.5% and 8.5%, respectively). Among annual personal and the household income of the patient, proportions of intangible cost were 262.6% and 67.6% respectively, suggesting that the patients were under huge spiritual and psychological pressure. Response rate of the approach, combined open-ended questions with iterative bidding game, was the highest (76.6%) among the three elicitation formats. Considered the characteristics of data being gathered, the approach seemed to be more reasonable. Further studies were needed to examine the results yielded from other WTP elicitation formats. We also noticed that the progression of disease was associated with the increase of direct and indirect costs, but not with the intangible cost. Data from the multiple linear stepwise regression analysis indicated that the types of hospital and commercial medical insurance were significantly different in explaining the variation of the intangible cost. CONCLUSION: Measures should be taken to reduce the intangible cost of hepatitis B-related diseases. The approach regarding the combination of open-ended questions with iterative bidding game should be recommended when carrying our further WTP studies of this kind.

[Evaluation on the efficacy of recombinant hepatitis B vaccine booster immunization in 2789 children aged over 10 years].

OBJECTIVE: To study the efficiency of booster immunization with different recombinant hepatitis B vaccines. METHODS: 2789 children aged over 10 years who had completed the basic immunization of hepatitis B vaccine under 1 year old were selected. All the sampled children were classified into four groups (A, B, C and D) and immunized with different hepatitis B vaccines produced by different companies respectively. Before booster immunization, their blood plasma specimens were detected for hepatitis B virus (HBV) surface antigen (HBsAg), antibodies to HBV surface antigen (anti-HBs) and antibodies to HBV core antigen (anti-HBc) by chemiluminescence. In each group, the anti-HBs positive children were immunized with one dosage and anti-HBs negative children were immunized three dosages of the same vaccine. Their blood specimens were collected again after 1 month, and detected for anti-HBs. RESULTS: The anti-HBs positive rates of A, B, C and D group were 36.43%, 37.59%, 42.91% and 46.46% respectively before immunization while 89.20%, 91.52%, 90.96% and 85.45% respectively after immunization with one dosage, 99.12%, 99.47%, 98.87% and 98.85% respectively after immunization with three dosages. The differences of anti-HBs positive rates in the four respective groups showed statistical significances between any two rates of pre-immunization, post-immunization with one dosage and post-immunization with three dosages (all P < 0.05). The anti-HBs positive conversion rates of four groups were 83.01%, 86.41%, 84.16% and 72.82% respectively after immunization with one dosage. The anti-HBs positive conversion rate of four groups were 98.62%, 99.16%, 98.03% and 97.84% respectively after immunization with three dosages and the difference of positive conversion rates in each group showed statistical significances between booster immunization with one dosage and booster immunization with three dosages. The average GMTs in anti-HBs positive children in the four groups were 2853.21, 6254.23, 3581.40 and 3021.32 mIU/ml respectively after immunization with one dosage. The average GMTs of anti-HBs negative children in the four groups were 273.08, 648.52, 387.87 and 245.36 mIU/ml respectively after immunization with one dosage, and were 632.30, 2341.14, 563.97 and 394.08 mIU/ml respectively after immunization with three dosages. CONCLUSION: Our data showed that it would be suitable to anyone to use the four vaccines for anti-HBs positive children aged over 10 years with one dosage and for anti-HBs negative children aged over 10 years with three dosage booster immunization.

[A sero-epidemiological study on hepatitis C in China].

OBJECTIVE: To better understand and measure the status of hepatitis C virus (HCV) infection, we conducted a sero-epidemiological study using the remaining blood samples and data of the nationwide survey of hepatitis B in Chinese residents which was carried out in 2006. METHODS: The anti-HCV reagent was screened out from the reagents by the HCV infection blood serum plate with anti-HCV positives or negatives. This plate recognized the Murex 3.0 and Ortho 3.0 reagents as gold standards. Anti-HCV in the blood samples were tested using this reagent and confirmed by Chiron HCV RIBA 3.0 reagents. RESULTS: Among the population aged 1 year to 59 year-olds, the overall prevalence rate of anti-HCV was 0.43% (95%CI: 0.33% - 0.53%), with the rates of anti-HCV among males and females as 0.46% and 0.40%, respectively. The prevalence rate of anti-HCV in urban area was 0.43%, and in rural area it was 0.43%. The prevalence rate of anti-HCV in the Eastern, Middle and Western areas were 0.37% (95%CI: 0.21% - 0.53%), 0.67% (95%CI: 0.40% - 0.94%) and 0.31% (95%CI: 0.20% - 0.42%) respectively. The prevalence rates of anti-HCV for the three areas did not show significant differences, statistically. The prevalence rate of anti-HCV in the South and North areas were 0.29% (95%CI: 0.21% - 0.52%) and 0.53% (95%CI: 0.38% - 0.64%) respectively. CONCLUSION: Our data revealed that China was in the low prevalence area for hepatitis C infection and the results also suggested that the comprehensive measures for HCV control and prevention had been successfully achieved in the country.