Decline of hepatitis B carrier rate in vaccinated and unvaccinated subjects: sixteen years after newborn vaccination program in Taiwan

Taiwan was an endemic area for hepatitis B virus (HBV) infection, and related liver diseases cause a significant drain of public resources. To control the endemic, a nation-wide newborn vaccination program was started in 1985. We reviewed the results of the annual survey for HBV surface antigen (HBsAg) performed in freshmen class of two high schools in Hualien, eastern Taiwan, from 1991 to 2001. A total of 10,194 students, most of them 15 years old, were tested for serum HBsAg using enzyme immunoassays. There is a significant trend (P < 0.0001) of decreasing HBsAg carrier rate from 20.3 to 4.4% in males and 14.3% to 2.4% in females, respectively, over 11 years. The HBsAg carrier rate was 16.0-20.3% in students surveyed during 1991-1993 (born more than 6 years before the start of the national vaccination program), which decreased to 7.7-11.9% during 1994-1999 (born 1-6 years before the program). It further declined to 4.7% and 3.4% in 2000 and 2001 (born after the start of the program). The HBsAg carrier rate in male students was significantly higher than that in female students in most of the years. The HBV newborn vaccination program not only successfully prevented most of the perinatal transmission of HBV but also reduced horizontal transmission of HBV to children born up to 6 years before the start of the program. Also, the protection persisted for at least 15 years.     

Seroprevalence of Hepatitis-B infection amongst Taiwanese university students 18 years following the commencement of a national Hepatitis-B vaccination program

In Taiwan, the nation-wide Hepatitis-B virus (HB) vaccination program was first launched in July 1984 and was directed to those infants born to hepatitis B surface antigen (HBsAg) carrier mothers in Taiwan. From July 1986 onwards, all infants born in Taiwan were immunized against HB. This study examined the HB-infection status amongst students at a Taiwanese university 18 years subsequent to the implementation of universal HB vaccination. A total of 1,969 new university entrants in 2005 were grouped into 1 of 3 distinct birth cohorts according to their HB-vaccination schedule (cohort-1 students born prior to July 1, 1984; cohort-3 students born subsequent to June 30, 1986) and were examined for their serum HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) status. Immunity arising from vaccination was defined as an anti-HBs level 10 mIU/ml. We observed a trend toward a decreasing anti-HBc-positive rate and a decreasing HBsAg carrier rate from, respectively, 26.5 and 8.7% for cohort-1 to 4.7 and 1.7% for cohort-3 students. The prevalence of students featuring seronegativity for all three HB markers increased from 12.3% for cohort-1 to 48.8% for cohort-3 individuals. Amongst the 1,695 subjects revealing seronegativity for HBsAg and anti-HBc, their anti-HBs level was analyzed according to their birth year. The prevalence of students featuring a non-protective anti-HBs level increased from 11.9% for birth-year 1984 individuals to 48.2% for birth-year 1987 students. The introduction of HB vaccine has effectively reduced the transmission of HBV infection in Taiwan, 18 years subsequent to the commencement of the universal HB-vaccination program. A "waning-off" effect of anti-HBs seropositivity acquired from the HB vaccination program has also been observed.     

Impact of the Expanded Program of Immunization against hepatitis B infection in school children in Malaysia

The implementation of the Expanded Program of Immunization (EPI) in 1989 has dramatic impact on hepatitis B virus (HBV) infection in school children in Malaysia. A cross-sectional seroprevalence study of HBV infection in 190,077 school children aged 7–12 years from 1997 to 2003 showed a steady decline of HBV surfacce antigen (HBsAg) prevalence rate from 2.5% for children born in 1985 to 0.4% among school children born in 1996. The overall prevalence of HBsAg was 0.6%, 0.7% in males and 0.6% in females. Over 92.7% of school children had been vaccinated with HBV vaccine, in which 93.7% were vaccinated under the EPI and 6.3% on voluntary basis. The school children vaccinated under EPI had a 0.4% HBsAg carrier rate, which was significantly lower than school children vaccinated on a voluntary basis (HBsAg carrier rate 1.3%) and non-vaccinated school children (HBsAg carrier rate 2.7%), suggesting that HBV vaccination of infants was the most effective measure in preventing vertical transmission of HBV in the hyperendemic region.     

Prevalence of HBsAg carriers in native and immigrant pregnant female populations in Israel and passive/active vaccination against HBV of newborns at risk.

Israel has no official prevention policy at present against perinatal and horizontal transmission of hepatitis B virus (HBV) infection in newborns and children at risk. The present study was designed to assess the prevalence of HBV carrier state in a population of 11,123 pregnant women at term. Among this population (mean age 29.7 +/- 5.9), 98 women (0.88%) were found to be asymptomatic HBsAg+ carriers, and 97% of these carriers were anti-HBe+. Evidence for HBV replication, as determined by serum HBV-DNA, was established in 6.6% of the HBsAg+/anti-HBe+ population. The HBsAg carrier rate was strongly influenced by religion, continent, and country of birth of the carrier mothers. The highest relative carrier rate was found among women of Moslem origin (4.3%), as compared to Jewish women (0.67%). Most carrier women were born in Israel (56.1%) to mothers who had emigrated from regions with intermediate or high endemicity of HBV, such as North Africa or the Middle East. In these groups, the HBsAg carrier rate ranged between 1.2 and 3.0%. Ninety-three percent of newborns receiving passive/active vaccination against HBV developed protective levels of anti-HBs. Finally, evidence for horizontal transmission of HBV was found in 19.3% of 83 non-vaccinated children in families of HBsAg carriers. The present study therefore establishes HBsAg prevalence rates in specific risk groups of women at term and confirms the need for an official policy on immunization against HBV in Israel. Since over 50% of women at term belong to the defined risk groups, universal active vaccination of the entire newborn population each year is suggested as the most rational and needed policy in Israel.     

Clinical characteristics of hepatitis B virus infection in middle school students born after the universal infant vaccination program in Shanghai,China

The aim of this study was to investigate the prevalence of hepatitis B surface antigen (HBsAg) and clinical characteristics of middle school students infected with hepatitis B virus (HBV) after initiation of the HBV immunization program in China. A total of 82,156 serum samples were collected from students in 33 junior schools and 25 senior schools. HBsAg was tested by ELISA. Samples from HBsAg-positive students were collected and analyzed for HBV serum markers, alanine aminotransferase (ALT), HBV DNA levels, and HBV genotypes. The overall prevalence of HBsAg was 1.11% in middle school students in Shanghai, China. The prevalence of HBsAg in students born during the immunization program to HBsAg-positive mothers was significantly higher than that in students born during the universal vaccination program (1.47% vs 0.78%, P < 0.01). Only HBV genotypes B and C were found in these infections, and genotype C was the dominant one. Twenty-one (13.0%) of 162 HBsAg-positive students had active hepatitis B, and 18 were hepatitis B e antigen (HBeAg) positive. The universal infant vaccination program has reduced the prevalence of HBsAg significantly. HBeAg-positive hepatitis B, however, needs to be monitored among the students in whom vaccination failed.     

Perinatal transmission of hepatitis B virus in Thailand

Perinatal transmission of hepatitis B virus (HBV) from asymptomatic HBsAg carrier mothers to their infants was studied in 78 mother-infant pairs by determination of HBsAg, HBeAg and anti-HBe both in the mothers and in their infants at regular intervals for those children up to the time when they reached at least one year of age. Twenty-five out of the 78 (32.1%) infants born to these mothers were HBsAg-positive 2-6 months after birth and they remained so throughout the observation period of at least one year or more. Perinatal HBV transmission occurred only in infants born to HBsAg carrier mothers who were HBeAg-positive (92.6%) but not in those born to HBsAg carrier mothers who had no detectable HBeAg. This study suggests that preventive measures against HBV transmission during the perinatal period should be taken only for infants born to HBsAg carrier mothers who are HBeAg-positive. In addition, the active immune response to HBV was studied in 75 non-HBsAg carrier infants born to HBsAg carrier mothers by determination of anti-HBs at one year of age or older. Forty-three of these infants were treated with HBIG at birth and 32 infants received no treatment. It was found that infants born to HBsAg carrier mothers who were HBeAg-positive had a better active immune response (84.2% positive for anti-HBs) than infants born to HBsAg carrier mothers who had no detectable HBeAg or anti-HBe (14.3% and 20.4% positive for anti-HBs respectively).     

Hepatitis B surface antigen confirmatory testing for diagnosis of hepatitis B virus infection in Taiwan

This study aimed to examine the application of hepatitis B surface antigen (HBsAg) confirmatory testing when diagnosing hepatitis B infection among young persons in Taiwan with a low prevalence rate of hepatitis B infection. HBsAg status, the presence of antibodies against HBsAg (anti-HBs), and the presence of antibodies against hepatitis B core antigen (anti-HBc) were compared among 403 graduate students (mean age 22.8 ± 0.7 years) and 1,745 undergraduate students (18.6 ± 1.0 years) from one university, and 367 adult subjects (41.1 ± 15.8 years) in 2008. Any HBsAg-positive subjects were tested with an HBsAg confirmatory test. Chi-square tests for trend and predictive values of positivity (PVP) when using HBsAg-positive only for determining confirmed cases of hepatitis B infection were compared across the three cohorts. The prevalence of HBsAg positivity among subjects decreased from 16.3% in the adults to 5.2% in the graduate students and then to 2.8% for the undergraduate students (P = 0.0007). The PVP of HBsAg testing when determining cases of hepatitis B decreased from 0.97 for the adults to 0.81 for the graduate students and then to 0.56 for the undergraduate students (P < 0.0001). Thus, a significant decrease in the true-positive rate of HBsAg among the students born after the introduction of hepatitis B vaccination was observed only when HBsAg testing was applied. Additional neutralization tests may therefore become mandatory for persons with a positive HBsAg test result who were born after the commencement of the universal neonatal hepatitis B vaccination program in Taiwan.     

Hepatitis B virus infection among mentally retarded patients in institutions, Okinawa, Japan

To determine whether transmission of hepatitis B virus occurs among mentally retarded patients in six institutions, from 1986 to 1988, 373 patients (males 203, females 170, 18-53 years of age, mean age 29.9) were tested for hepatitis B markers. Seventy five of them had Down's syndrome. Overall prevalences were 9.1% for hepatitis B surface antigen (HBsAg), 39.7% for antibody to HBsAg (anti-HBs) and 48.0% for antibody to hepatitis B core antigen (anti-HBc). Prevalence of HBsAg was significantly higher in patients with Down's syndrome than in other mentally retarded patients. Five patients (three males and two females) in four institutions were infected with hepatitis B virus during the two years of observation. Four of these five patients were the other mentally retarded and became both anti-HBs and anti-HBc positive. The remaining one, who was 29 years old and Down's syndrome, became an HBsAg carrier. These observations indicate that hepatitis B virus transmission frequently occurs among mentally retarded patients in institutions and therefore vaccination of susceptible institutionalized patients is necessary. Vaccination to patients with Down's syndrome is particularly warranted, because they are uniquely predisposed to develop chronic hepatitis B infection following exposure.     

Hepatitis B vaccination in children: The Taiwan experience

The world's first nationwide hepatitis B virus (HBV) universal vaccination program for infants was launched in Taiwan in July, 1984. All infants received three to four doses plasma or recombinant HBV vaccines. In addition, infants of HBeAg-positive mothers received 0.5 ml of hepatitis B immunoglobulin within 24 hours after birth. The vaccination coverage rate is as high as 97%. Seroprevalence of hepatitis B surface antigen (HBsAg) declined from 9.8% (prevaccination period) to 0.6% in children in Taipei City after 20 years of mass vaccination. The seropositive rates for HBsAg, antibody to HBsAg, and antibody to hepatitis B core antigen were 1.2%, 50.5%, and 3.7%, respectively, in those born after the vaccination program (< 20 years old) in 2004. In line with the decrease of chronic HBV infection, the incidence of hepatocellular carcinoma (HCC) also decreased in children in Taiwan. From 1981 to 1994, the incidence of HCC in 6- to 9-year-olds declined from 0.52/100,000 for those born between 1974 and 1984 to 0.13 for those born between 1984 and 1986 (p < 0.001). We extended the observation to 2000, the incidence of HCC per 100,000 children declined from 0.54 to 0.20. The prevalence of a determinant mutants (amino acids 121–149 of HBsAg) in Taiwanese carrier children was 7.8% (eight out of 103) in 1984, increased to 19.6% (10 out of 51) in 1989, peaked at 28.1% (nince out of 32) in 1994, and remained stationary at 23.1% (three out of 13) and about 25% in 1999 and 2004, respectively; it was higher in those fully vaccinated compared with those not vaccinated. The other group of subjects who are susceptible to vaccine failure is the immunocompromized hosts. We observed some de novo HBV infection in children after liver transplantation. Despite of the success of hepatitis B immunization, childhood chronic HBV infection and HCC were not eliminated by the universal vaccination program. Among those HBsAg carriers born after the vaccination program, 89% of their mothers were found to be positive for HBsAg, indicating the importance of maternal transmission. This was also true in the mothers of children with HCC, of them 96% were HBsAg positive. After two decades of universal infant HBV vaccination, we found this program provides long-term protection for up to more than 20 years, and a universal booster is not required for the primary HBV vaccinees before adulthood. Mother-to-child transmission, although largely diminished, is still the main cause for immunoprophylaxis failure. The emergence of escape mutant did not impose increased risk of chronic infection at present. Nevertheless, development of new vaccines may overcome the vaccine failure.     

Hepatitis B virus transmission pattern and vaccination efficiency in Uzbekistan

A national program of universal vaccination for the prevention of chronic hepatitis B virus (HBV) infection was launched in Uzbekistan since 1998. To evaluate the 6 years' outcome of the program, 567 children were enrolled in the study. Among those enrolled, 333 had immunized with adw2 type based Engerix-B (Glaxo Smith Kline Beechem, Rixensart, Belgium) and 48 with adr type based Hepavax-Gene (Green Cross Vaccine Corporation, Korea). A cohort of 186 children born before the immunization program, was also included in the study. When 45 vaccinated children were compared to age/sex-matched 45 unvaccinated children, the sero-prevalence of HBsAg was 0 versus 11% (P = 0.56), and of anti-HBc was 0% versus 44% (P < 0.0001), respectively. Loss of anti-HBs was observed in 18.4% after 5 years. Among 13 HBsAg carriers found in this study, genotype HBV/D was found in 69%, HBV/A in 23% (all in unvaccinated group) and HBV/C in 8% (in vaccinated group). No significant differences were observed in this study between groups which received different vaccine formulation. Phylogenetic analysis of the HBV isolates obtained from family members of the HBsAg-positive children, revealed evidence suggesting that transmission in the vaccinated group was exclusively perinatal, whereas in the unvaccinated group horizontal transmission pattern predominated. In conclusion, HBV universal vaccination is efficient in Uzbekistan irrespective of the vaccine formulation used, because the horizontal transmission pattern predominates currently in this endemic region.     

Seroprevalence of hepatitis B virus infection in children in Taipei, 1989: five years after a mass hepatitis B vaccination program

A nationwide hepatitis B vaccination program was launched in Taiwan in 1984. To study the impact of this ongoing program on hepatitis B virus (HBV) infection, a follow-up seroepidemiologic study was carried out in 1989 in a Taipei district where pre-vaccination seroepidemiology had been studied. HBV markers were studied in 1134 apparently healthy children (619 boys and 515 girls) under 13 years of age between March and July 1989. The prevalence of hepatitis B surface antigen (HBsAg) in children under 5 years of age decreased from 9.3% in 1984 to approximately 2% in 1989. A significant decrease in HBsAg prevalence and hepatitis B core antibody in 5- to 8-year-old children who were not immunized against HBV showed that horizontal infection among the older children had also decreased. Thus, this program not only protected vaccinated subjects; the reduction in numbers of highly infectious young HBV carriers also contributed to a lower prevalence of hepatitis B infection and carrier rates in some older children. This study demonstrates that hepatitis B vaccination is effective in protecting the majority of children in hyperendemic areas from HBV infection and from becoming chronic carriers.     

Hepatitis B virus in Gizan, Saudi Arabia

The enzyme-linked immunosorbent assay (ELISA) was used to study the prevalence rates for hepatitis B virus surface antigen (HBsAg), antibody to surface antigen (anti-HBs), and antibody to core antigen (anti-HBc) in 724 voluntary donors, students, pregnant women and those seeking treatment for minor ailments in the Gizan area of Saudi Arabia. Tests for hepatitis B e antigen (HBeAg) and e antibody (anti-HBe) were made in HBsAg positive sera. There was serological evidence of an existing or earlier infection in 337 Saudis (46.5%), of whom 12.7% were HBsAg carriers, 25.4% were positive for anti-HBs, and 8.4% were positive only for anti-HBc. The percentage of HBsAg carriers was 19.9% and 9.3% in males and females, respectively (p less than 0.001). The evidence of existing or earlier infection in males (58.7%) was significantly higher than in females (38.7%) (p less than 0.001), with no intersex difference in anti-HBs or anti-HBc. No difference was observed in the positivity of either of the markers, alone or together, between the cord blood and the female population in the child-bearing age of 20-39 years. Corresponding to the values in other age groups, there was an overall fall in the number of HBsAg carriers during adolescence as well as in 20-39-year-old females. Among the HBsAg carriers, there was no significant difference between the two sexes for HBeAg and anti-HBe positivity. The HBsAg carrier rate of 19.9% in males is consistent with the high male dominant prevalence of hepatocellular carcinoma in the Gizan area.(ABSTRACT TRUNCATED AT 250 WORDS)     

Baseline seroepidemiology of hepatitis B virus infection in children in Taipei, 1984: a study just before mass hepatitis B vaccination program in Taiwan

Hepatitis B virus (HBV) markers were studied by radioimmunoassays in serum samples of 1,200 (647 male, 553 female) apparently healthy children under 15 years of age in Taipei between June and October 1984. The prevalence rate of hepatitis B surface antigen (HBsAg) was 5.1% in infancy, increased to 10.7% between 1 and 2 years of age, and then remained constant at about 10% thereafter. The prevalence rate of surface antibody (anti-HBs), core antibody (anti-HBc), and seropositivity (at least one marker of hepatitis B detectable) were 39.0, 30.5, and 52.5%, respectively, in infancy, then decreased to 10.7, 14.3, and 17.9%, respectively, between 1 and 2 years of age. Thereafter, the antibody prevalence increased in parallel with age. By the age of 13-14 years, nearly half of the children were infected by HBV. The results suggested that in our children, most HBsAg carriers resulted from infections before 3 years of age, and HBV infections after 3 years of age infrequently resulted in a carrier state. One hundred (83.3%) of the 120 HBsAg-positive children had hepatitis B e antigen (HBeAg), indicating high prevalence in young asymptomatic HBsAg carriers. The prevalence rate of HBeAg tended to decrease with age and a reversed trend was observed with anti-HBe. Our study, just before our government extends mass hepatitis B vaccination program from newborns to children, provides background seroepidemiologic data of HBV infections in the healthy children in Taiwan.     

Age- and sex-related study of hepatitis B virus chronic carrier state in infants from an endemic area (Senegal)

This report concerns hepatitis B virus (HBV) infections observed in 155 infants from Senegal, studied with a view to determining the factors involved in development of the chronic carrier state. A chronic carrier state was observed in 50.3% of the infants. This study confirms that the risk of chronic carriage is linked to age. This risk declines very rapidly with age, falling from 82% in infants under 6 months old, to 15% in children between the ages of 2 and 3 years. Spontaneous elimination of hepatitis B surface antigen (HBsAg) is uncommon in HBsAg carriers during childhood. The difference observed in chronic carriage between males and females is due to a difference in susceptibility of the two sexes to the development of the chronic carrier state: HBV infections (before 2 years of age) lead to a chronic carriage in 77% of males as against 50% of females. These conclusions are important in view of the immunisation programs being carried out against hepatitis B virus in endemic areas. For a maximum efficacy, vaccination must be carried out at birth, or shortly afterwards.     

Prophylactic vaccination against hepatitis B: achievements,challenges and perspectives

Large-scale vaccination against hepatitis B virus (HBV) infection started in 1984 with first-generation vaccines made from plasma of chronic carriers containing HBV surface antigen (HBsAg). Thereafter, it was replaced in most countries by second-generation vaccines manufactured in yeast cells transformed with gene S encoding HBsAg. Both generations of vaccines have been applied for universal neonate and early childhood vaccination worldwide and have led to a 70–90 % decrease in chronic HBV carrier rates. However, 10–30 % of newborns from HBsAg/HBeAg-positive mothers cannot be protected by passive/active vaccination alone and become chronic HBV carriers themselves. Asymptomatic occult HBV infections are frequent even in those who have protective levels of anti-HBs. Suboptimal protection may be due to heterologous HBsAg subtypes that are present in 99 % of HBV carriers worldwide. Second-generation vaccines contain partially misfolded HBsAg and lack preS1 antigen that carries the major HBV attachment site and neutralizing epitopes. Third-generation vaccines produced in mammalian cells contain correctly folded HBsAg and neutralizing epitopes of the preS antigens, induce more rapid protection, overcome nonresponse to second-generation vaccines and, most importantly, may provide better protection for newborns of HBV-positive mothers. PreS/S vaccines expressed in mammalian cells are more expensive to manufacture, but introduction of more potent HBV vaccines should be considered in regions with a high rate of vertical transmission pending assessment of health economics and healthcare priorities. With optimal vaccines and vaccination coverage, eradication of HBV would be possible.     

Significance of isolated anti-HBc seropositivity by ELISA: implications and the role of radioimmunoassay.

Hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) are excellent markers for HBV infection and its immunity. The significance of isolated antibody to HBV core antigen (anti-HBc) seropositivity is not certain. To elucidate this, sera from 638 Chinese adult subjects, aged 18-52 years, seronegative for both HBsAg and anti-HBs, were tested for anti-HBc. Fifty-one (8%) were found to have an isolated anti-HBc seropositivity by ELISA, and all were negative for IgM-anti-HBc. The anti-HBc persisted in all subjects who attended follow-up for hepatitis B vaccination (n = 48) for a period of 8 months. These 48 subjects received 3 doses of hepatitis B vaccine (HB-VAX, 10 micrograms or 20 micrograms) at 0, 1, and 6 months: 72.9% developed a primary anti-HBs response (suggestive of a false-positive anti-HBc seropositivity), 4.2% developed an anamnestic or secondary anti-HBs response, and 22.9% did not develop an anti-HBs response. Increasing the cutoff point of the ELISA or reconfirmation with radioimmunoassay (RIA) reduced only a minor half of the false positives. This low specificity of anti-HBc ELISA/RIA, together with the high rate of anti-HBs response to hepatitis B vaccine, indicates that subjects with isolated anti-HBc seropositivity should be included in vaccination programs.     

Multicenter trial on the efficacy of HBIG and vaccine in preventing perinatal hepatitis B. Final report

In an attempt to interrupt perinatal transmission of hepatitis B, 92 infants born to HBsAg carrier mothers (49 to HBeAg-positive mothers, 30 to anti-HBe-positive with abnormally elevated ALT levels, and 13 to HBeAg/anti-HBe-negative mothers) received 0.5 ml/kg BW of HBIG at birth and at 1 month of age. Three IM injections of hepatitis B vaccine were given at 3, 4, and 9 months of life. All babies who were given the three doses of vaccine developed an active anti-HBs response: of these, 53 (62.3%) had antibody titers higher than 1,000 mIU/ml, 29 (34.2%) had levels between 100 and 1,000 mIU/ml, and the other three (3.5%) were below 100 mIU/ml. At the end of the 2-year follow-up, these three poor responders became anti-HBs negative, whereas the others still had antibody. All but three babies were protected by HBIG plus vaccine treatment. Two chronic HBV infections occurred within 6 months of life presumably because the babies were already infected when prophylaxis started. The third baby became an HBsAg carrier at 9 months of age in spite of a previous response to the vaccine. Simultaneous presence of HBsAg of y specificity and anti-HBs (anti-a) was still detectable at 24 months of age. The vaccine was well tolerated. Passive plus active immunization is an effective procedure for preventing perinatally transmitted HBV infection.     

广州某高等医学院校研究生乙肝疫苗接种情况调查

目的了解广州某高等医学院校研究生乙肝疫苗接种情况，为乙肝防治工作提供依据。方法对广州某高等医学院校2006年入学的1139名研究生进行入学体检现况调查，采集血标本用ELISA法检测乙型肝炎表面抗原（HBsAg）和表面抗体（HBsAb）。同时发放乙肝疫苗接种情况调查表，调查乙肝疫苗接种的年代、次数，是否加强接种及时间。用SAS统计软件包对结果进行X^2检验分析。结果广州某高等医学院校06级研究生HBsAg阳性率为2．90％，曾注射乙肝疫苗组，HBsAg阳性率显著低于从未注射疫苗组（1．15％ vs． 21．69％，P〈0．0001），而HBsAb阳性率则显著高于从未注射疫苗组（81．54％ vs．44．58％，P〈0．0001）。有17．31％曾接种乙肝疫苗者未能达到预期预防效果。不同年龄研究生乙肝疫苗接种效果有差异（P=0．0462），随着年龄的增加，HBsAb阳性率有下降趋势。女性乙肝疫苗接种效果较男性好（80．0％ vs．84．87％，P=0．0468）。接种年限在3年内者，HBsAb阳性率较其他年限高（0—3年 vs．4—6年，P=0．0089；0—3年 vs．7—9年，P=0．0172；0—3年 vs．〉9年，P=0，0474）。注射大于3针（即加强接种）免疫效果较注射3针者好，差异有统计学意义（P=0．0093）。结论随着年龄的增加，乙肝疫苗接种效果（HBsAb阳性率）逐渐降低。男性群体较女性群体更易成为乙型肝炎病毒的易感人群。对接种年限大于3年者，可进行抗-HBs监测，及时进行加强免疫。     

韶关市1～5岁儿童乙型肝炎血清学调查结果分析

目的了解乙肝疫苗纳入免疫规划后,韶关市1～5岁儿童乙肝病毒携带率与乙肝免疫水平,评价现阶段儿童乙肝的预防控制效果。方法从全市10个县（市、区）中采取分层整群随机抽样方法,选取2008年在幼儿园（托儿所）1～5岁儿童作为调查对象,收集血清样本采用酶联免疫吸附试验（ELISA）检测乙肝表面抗原（HBsAg）和表面抗体（抗-HBs）。结果共采集1～5岁儿童血清1485份,HBsAg阳性率为0.88%,随年龄增长有增高的趋势,男性0.93%、女性0.82%,经检验两者间差异无统计学意义（χ2=0.0586,P〉0.05）,地区间最高的是南雄市（0.97%）,最低的武江区（0.80%）,经检验两者间差异无统计学意义（χ2=0.0808,P〉0.05）;抗-HBs阳性率为65.86%,随年龄增长有下降趋势,男性65.01%、女性66.80%,经检验两者间差异无统计学意义（χ2=1.5424,P〉0.05）,地区间最高的武江区（66.27%）,最低的是乳源县（65.47%）,经检验两者间差异无统计学意义（χ2=0.0688,P〉0.05）。结论韶关市乙肝疫苗免疫规划实施后,5岁以下儿童HBsAg携带率明显降低,预防效果显著;抗-HBs阳性率偏低,加大新生儿乙肝疫苗接种剂量。     

Seroprevalence and risk factors for hepatitis B infection in an adult population in Northeast China

Background and aim: The prevalence of the hepatitis B virus (HBV) is higher in adults than in children. We determined the seroepidemiology of HBV infection in an adult population in JiLin, China, to guide effective preventive measures.Methods: A cross-sectional serosurvey was conducted throughout JiLin, China. A total of 3833 people was selected and demographic and behavioral information gathered. Serum samples were tested for HBV markers and liver enzymes.Results: The prevalence of the hepatitis B surface antigen (HBsAg), the antibody to the hepatitis B surface antigen (anti-HBs), the hepatitis B e antigen (HBeAg), the antibody to HBeAg (anti-HBe), and the antibody to the hepatitis B core antigen (anti-HBc) were 4.38%, 35.66%, 1.38%, 6.65%, and 40.88%, respectively. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly higher among HBsAg (+) than HBsAg (-) subjects. By multivariate logistic regression analysis, independent predictors for chronic HBV infection were smoking, poor sleep quality; occupation as private small-businessmen, laborers, or peasants; male gender; family history of HBV; personal history of vaccination; and older age. Independent predictors for exposure to HBV were large family size, occupation as a private small-businessman, male gender, family history of HBV, personal history of vaccination, and older age. Independent predictors for immunity by vaccination were occupation as a private small-businessman, high income, personal history of vaccination, and young age. Independent predictors for immunity by exposure were drinking, male gender, personal history of vaccination, and older age.Conclusions: The prevalence rate of HBV infection (4.38%) was lower than the previous rate of general HBV vaccination. However, 44.59% of the population remained susceptible to HBV. The prevalence of HBV infection was high in young adults, private small-businessmen, peasants, those with a family history of HBV, and males. Therefore, immunization of the non-immune population is reasonable to reduce hepatitis B transmission between adults.