A complex hepatitis B virus (X/C) recombinant is common in Long An county, Guangxi and may have originated in southern China.

Recently, a complex (X/C) hepatitis B virus (HBV) recombinant, first reported in 2000, was proposed as a new genotype; although this was refuted immediately because the strains differ by less than 8 % in nucleotide distance from genotype C. Over 13.5 % (38/281) of HBV isolates from the Long An cohort in China were not assigned to a specific genotype, using current genotyping tools to analyse surface ORF sequences, and these have about 98 % similarity to the X/C recombinants. To determine whether this close identity extends to the full-length sequences and to investigate the evolutionary history of the Long An X/C recombinants, 17 complete genome sequences were determined. They are highly similar (96-99 %) to the Vietnamese strains and, although some reach or exceed 8 % nucleotide sequence difference from all known genotypes, they cluster together in the same clade, separating in a phylogenetic tree from the genotype C branch. Analysis of recombination reveals that all but one of the Long An isolates resembles the Vietnamese isolates in that they result from apparent recombination between genotype C and a parent of unknown genotype (X), which shows similarity in part to genotype G. The exception, isolate QL523, has a greater proportion of genotype C parent. Phylogeographic analysis reveals that these recombinants probably arose in southern China and spread later to Vietnam and Laos.

[A prospective study of the relationship between serum hepatitis B virus DNA and the risk of primary liver cancer].

OBJECTIVE: To determine the relationship between the serum hepatitis B virus (HBV) DNA and the risk of primary liver cancer (PLC). METHODS: Farmers aged 30 to 55 years in Long An county were recruited in this study Blood samples were collected and the sera were tested for HBsAg using Enzyme-Linked ImmunoSorbent Assay (ELISA), and the HBsAg-positive sera were further tested for viral DNA using nested polymerase chain reaction (nPCR). The study subjects were divided into three groups. The first group was positive for both HBsAg and HBV DNA. The second group was positive for HBsAg but negative for HBV DNA. Age-, sex-, residence-matched HBsAg negative controls for group 1 and group 2 were enrolled in the third group. The cohort was followed up for four years. RESULTS: The positive rate of HBsAg in these farmers was 14.52% (3975/27,379), and the HBV DNA positive rate in HBsAg positive subjects was 40.35% (1604/3975). The total PLC incidence rate in Group 1 and 2 was 672.45 /100,000 person-years (PY), significantly higher than that in Group3 (17.19 /100,000 PY). The relative risk (RR) was 39.123, and the 95% confidence interval (CI) was 9.018-159.146. The PLC incidence rate of Group 1 (984.03/100,000 PY) was significantly higher than that of Group2 (324.38 /100,000 PY). The RR was 3.034, and the 95% CI was 1.795-5.125. Multivariate analyses of Group1 and 2 with Cox model showed that sex, age, serum HBV DNA, and family history of PLC were independent risk factors of PLC. CONCLUSION: HBV DNA and HBsAg positive subjects have a higher chance to develop PLC than HBV DNA negative-, HBsAg positive subjects.

HBV A1762T, G1764A mutations are a valuable biomarker for identifying a subset of male HBsAg carriers at extremely high risk of hepatocellular carcinoma: a prospective study.

OBJECTIVES: Surveillance of hepatocellular carcinoma (HCC) can detect small tumors for resection but at a huge cost of health resources. The challenge is to reduce the surveillance population. We reported that 96% of HCC patients but only 24% of controls were infected with the hepatitis B virus (HBV) with A(1762)T, G(1764)A mutations in Guangxi, China. It is likely to be extremely beneficial in terms of cost and resources if a significant number of tumors can be detected early by screening this selected population. Our aim is to test this hypothesis. METHODS: A cohort of 2,258 hepatitis B surface antigen-positive subjects aged 30-55 yr was recruited in Guangxi. Following evaluation of virological parameters at baseline, HCC is diagnosed by 6-monthly measurements of serum alpha-fetoprotein levels and ultrasonographic examinations. RESULTS: Sixty-one cases of HCC were diagnosed after 36 months of follow-up. The HCC rate was higher in the mutant than wild-type group (P < 0.001, rate ratio [RR] 6.23, 95% confidence interval [CI] 2.83-13.68). The HCC rate in the male mutant group was higher than that in the male wild-type group (P < 0.001, RR 11.54, 95% CI 3.58-37.24). Specifically, 93.3% of male cases are infected with the mutant. Multivariate analyses showed that in men, increasing age and A(1762)T, G(1764)A double mutations are independently associated with developing HCC. CONCLUSIONS: HBV A(1762)T, G(1764)A mutations constitute a valuable biomarker to identify a subset of male HBsAg carriers aged >30 yr at extremely high risk of HCC in Guangxi, and likely elsewhere.

Long-term antibody persistence study (3 years after last dose) of the 7-valent pneumococcal conjugate vaccine in young children in China.

BACKGROUND: In a previous study, Chinese infants were vaccinated with 7-valent pneumococcal conjugate vaccine (PCV7) ⩾7days before routine diphtheria, tetanus, and acellular pertussis vaccine (DTaP); PCV7 administered concomitantly with DTaP (PCV7+DTaP); or DTaP alone. This study examined antibody persistence at a single time point 3years after the last vaccination. METHODS: Children who participated in the prior PCV7 study were eligible to participate. A single blood sample was drawn at enrollment. Immunoglobulin G (IgG) geometric mean concentrations (GMCs) specific to the PCV7 serotypes and percentages of subjects with IgG ⩾0.35µg/mL were compared for subjects receiving PCV7 versus PCV7+DTaP (concomitant) and for PCV7 or PCV7+DTaP (concomitant) versus DTaP alone. IgG concentrations at 3years after the last vaccination were also compared with those after the infant series and toddler dose. RESULTS: Three years after the last vaccination with PCV7 or PCV7+DTaP (concomitant), IgG GMCs for most PCV7 serotypes were lower than after the infant series or toddler dose but remained above prevaccination concentrations. IgG GMC were similar between the PCV7 and PCV7+DTaP (concomitant) groups for 5 out of 7 serotypes but serotypes 4 and 19F were significantly lower in the PCV7+DTaP (concomitant) recipients. Three years after the last vaccination, IgG GMCs were significantly higher for 6 of 7 PCV7 serotypes among those receiving PCV7 or PCV7+DTaP (concomitant) compared with recipients of DTaP alone. Among subjects receiving DTaP alone, serotype-specific antibody concentrations were significantly higher for all serotypes 3years after the last vaccination compared with after the infant series. CONCLUSION: Three years after PCV7 vaccination, serotype-specific antibodies were lower than after the primary infant series but higher than prevaccination levels and higher among subjects who received PCV7 compared with those who did not. The immune response was comparable in children who received PCV7 with and without concomitant DTaP. CLINICAL TRIAL REGISTRATION: NCT01298544.

The association of HBV core promoter double mutations (A1762T and G1764A) with viral load differs between HBeAg positive and anti-HBe positive individuals: a longitudinal analysis.

BACKGROUND/AIMS: Although there have been a few reports regarding the effect of basal core promoter (BCP) double mutations (A1762T and G1764A) on hepatitis B viral loads, the association remains uncertain. We aim to determine the association after controlling for HBeAg - a strong confounding factor. METHODS: We selected randomly 190 individuals from a Chinese cohort of 2258 subjects for cross-sectional analysis and 56 of the 190 for longitudinal analysis of viral loads. RESULTS: In multivariable analysis of the cross-sectional data, BCP double mutations are significantly associated with lower viral loads in HBeAg positive subjects but no difference was found in anti-HBe positive subjects. Triple mutations at nucleotide (nt) 1753, 1762 and 1764 and mutations between nt 1809 and 1817, precore stop mutation (nt 1896) and genotype are not associated with viral loads in either HBeAg or anti-HBe positive subjects. Analysis of the longitudinal data yielded similar results to the cross-sectional data. Viral loads differ significantly between individuals infected with wild-type and BCP double mutations prior to HBeAg seroconversion but this difference is lost after seroconversion. CONCLUSIONS: BCP double mutations are associated with lower viral loads in HBeAg positive individuals but have no effect on the viral loads of anti-HBe positive individuals.

Safety and immunogenicity of a 7-valent pneumococcal conjugate vaccine (Prevenar): primary dosing series in healthy Chinese infants.

This was a randomized safety/immunogenicity evaluation of PCV7 primary series at 3, 4, 5 months in healthy Chinese infants. Eight hundred subjects were randomized to Group 1 (PCV7 > or =7 days before DTaP), or Group 2 (PCV7 with DTaP), or Group 3 (DTaP only). Erythema and induration/swelling were recorded at the PCV7 injection site at any individual dose in no more than 12% and 8% of subjects, respectively, and neither exceeded 2.5 cm in >1% of subjects. Fever >38.0 degrees C was observed in <13% of subjects at any individual dose. For each vaccine serotype, at least 90% of subjects (Groups 1 and 2) had IgG concentrations > or = 0.35 microg/mL after dose 3, except type 6B (Group 2) with 83.3%. PCV7 had an acceptable safety profile and was immunogenic in Chinese infants.

Hepatitis B virus pre-S deletion mutations are a risk factor for hepatocellular carcinoma: a matched nested case-control study.

A matched nested case-control study of 33 paired cases and controls was conducted, based on a study cohort in Long An county, Guangxi, China, to determine whether infection with hepatitis B virus (HBV) with pre-S deletions is independently associated with the development of hepatocellular carcinoma (HCC), without the confounding effects of basal core promoter (BCP) double mutations. The prevalence of pre-S deletions was significantly higher in HCC (45.5 %, 15 of 33) than the controls (18.2 %, 6 of 33) (P<0.01), under the control of the influence of BCP double mutations. Most of the pre-S deletions occurred in, or involved, the 5' half of the pre-S2 region and the difference between HCC (93.3 %, 14 of 15) and controls (66.7 %, four of six) was significant for this region (P=0.015). There was no significant difference in pre-S deletions between the BCP mutant group and BCP wild-type group (P>0.05), nor was the prevalence of pre-S deletions significantly different between genotypes B and C (P>0.1). These results suggest that pre-S deletions constitute an independent risk factor for HCC and their emergence and effect are independent of BCP mutations. The 5' terminus of pre-S2 is the favoured site for the deletion mutations, especially in HCC cases. Further prospective studies are required to confirm the role of these mutations in the development of HCC.

[Studies on the status of immune memory after completion of hepatitis B vaccination].

OBJECTIVE: To study the immune memory in vaccinees after the completion of a full schedule hepatitis B immunization. METHODS: One thousand and two hundred one infants born in 1987 -1989 were immunized with 3 doses of plasma derived hepatitis B vaccine, while 2484 newborn babies during 1996-1999 were injected with 3 doses of the yeast recombinant hepatitis B vaccine. All of the infants under observation were tested for HBsAg, anti-HBs and anti-HBc, in 2005. Of 959 individuals negative for anti-HBs (< 10 mIU/ml), HBsAg and anti-HBc, 228 were immunized with plasma-derived vaccine and 731 with yeast recombinant vaccine after birth. All of them were detected for anti-HBs 15 days after a booster of 10 Ipg yeast recombinant vaccine. In addition, interleukin-2 (IL-2) was detected in 11 non-responders and 22 responders after boostering, using an enzyme-linked immunospot (ELISPOT). The anti-HBs levels of 190 individuals (91 with plasma derived vaccine and 99 with yeast recombinant vaccine) who had had quantitative data on their antibody status after the primary hepatitis B vaccination, were compared with that after the boostering. RESULTS: Among the individuals who received plasma derived vaccine 16-18 years ago, 79.82% of them showed the signs of immune memory after one booster, with a geometric mean titer (GMT)of 325.69 mIU/ml. Of the individuals who received the yeast recombinant vaccine 6-9 years ago, 95.62% showed immune memory after one booster,with its GMT of 745.18 mIU/ml. Anti-HBs levels induced by the booster were associated with that after the primary immunization. The positive rate of IL-2 was 40.91% in subjects with good immune memory. However, IL-2 was not detected in non-responders after the booster (P < 0.01). CONCLUSION: Most of the individuals who had received a completed schedule of primary hepatitis B vaccination and seroconverted from anti-HBs positive to negative,showed the signs of having immune memory after the booster. Only a small proportion of the vaccinees had lost their immune memory during the long term follow-up period, suggesting that these individuals should receive a booster of hepatitis B vaccine in the highly endemic areas of hepatitis B. Hepatitis B virus; Immune memory; Booster immunization

[Study on the variations of hepatitis B virus status among people having received hepatitis B vaccine].

OBJECTIVE: To study the epidemiological pattern and trends of hepatitis B virus (HBV) in the area where people had been immunized by HBV vaccine for long time. METHODS: Through cluster sampling and cross-sectional study, relative information and blood samples from people in Long-an county by families were collected. Signals of HBV infection were tested by solid-phase reverse immunosorbent test. RESULTS: (1) The average HBsAg positive rate was 7.5% with anti-HBs as 44.5 %, and anti-HBc as 47.8%. The positive rates of HBsAg and anti-HBc among 0-19 year-olds were lower than those of > or = 20 year-olds. (2) The positive rates of HBsAg, anti-HBc and HBV infection among HBV vaccine immunized group were 2.8%, 12.0% and 12.5% respectively, comparing with which among the un-immunized group as 10.2%, 69.8% and 71.2% respectively. (3) The HBsAg positive rate of male was higher than the female's but with no significant difference of anti-HBs and anti-HBc between different sexes. (4) The average HBsAg positive rate of 0-19 years old group was only 2.4%, while that of 20-30 years old group was 13.6%-17.7% and dropped from 60 years old group and on. The anti-HBs positive rate of 0-19 years old people started to drop significantly by age. The anti-HBs and anti-HBc positive rates of > or = 20 years people were showing a rising trend by ages. CONCLUSION: It seemed obviously that the HBV epidemiological patterns had changed after HBV vaccine had been universally used for long time in newborns. The age peak of infection had been pushed backward for nearly 20 years. It had been proved that the HBV vaccine immunization program had obtained excellent efficacy.

[Variations of hepatitis B virus infection epidemic pattern after long-term HBV vaccine immunization].

OBJECTIVE: To study the epidemic pattern and trend of HBV infection in the area where the people had been immunized by HBV vaccine for 20 years. METHODS: The whole sampling method was applied in combination with cross-sectional investigation. Blood samples were taken from every member of families. Markers of HBV infection were determined by using solid-phase radioimmunoassay (SPRIA). RESULTS: (1) The average HBsAg positive rate was 7.5%. The positive rate of markers for HBV infection of 0-19 years old subjects were lower than those of > or = 20 years old subjects. (2) The positive rate of HBsAg of 0-19 years old subjects in 1985 was higher than that in 2005. The anti-HBs positive rate in 1985 stemmed to be higher with age. It was 12.4% in 1- age group to 53.8% in >60 years age group. While the result of 2005 showed that the anti-HBs positive rate of 0-19 years old subjects dropped with age. The anti-HBc positive rate in 1985 also tended to be higher with age. But the result of 2005 showed that the rate of 0-19 years old subjects was just 1.4% to 16.8%. CONCLUSION: The epidemic patterns of HBV infection have had significant variations in the target population. HBV vaccine immunization has obtained excellent efficacy.

[Efficacy of hepatitis B vaccination on hepatitis B prevention and on hepatocellular carcinoma].

OBJECTIVE: To evaluate the efficacy of hepatitis B vaccination on hepatitis B prevention and on hepatocellular carcinoma. METHODS: Birth cohort study, cross-sectional seroepidemiological survey, and surveillance of hepatitis B (HBV) and hepatocellular carcinoma were used to evaluate the efficacy of hepatitis B vaccination. RESULTS: During the 14 years after hepatitis B vaccination, the HBsAg positive rates were found to be 0.7% - 2.9%, with an average of 1.5%, and the protective rates were 83.5% - 96.6%. Hepatitis B virus infection rates of children immunized with hepatitis B vaccine were 1.1% - 5.1%, with an average of 2.2% and the protective rates of 93.5% - 98.4%. 15 years after hepatitis B vaccination, the incidence of hepatitis B dropped from 3.27/10 000 to 0.17/10 000, a 94.8% decrease, in the group of 0 - 19 year-olds. CONCLUSION: The universal infant hepatitis B vaccination has proved to be effective in reducing the incidence rate of acute hepatitis B as well as the mortality of hepatocellular carcinoma.