低出生体重儿乙肝疫苗免疫持久性与安全性分析

目的:研究低出生体重儿乙肝疫苗免疫持久性与安全性。方法:选择86例低出生体重儿作为研究组,另选取86例正常出生体重儿作为对照组,分别对两组接种全程酵母乙肝疫苗后的抗-HBs阳性率、抗体平均滴度进行检测,并观察不良反应的发生情况。结果:研究组与对照组接种全程乙肝疫苗后3年内的抗-HBs的有效阳性率分别是74%和72.1%(P0.05),抗体平均滴度分别是214.2 mIU/mL与210.8 mIU/mL(P0.05);6年内的抗-HBs的有效阳性率分别是82.6%和81.4%(P0.05),抗体平均滴度分别是178.6 mIU/mL与170.4 mIU/mL(P0.05)。研究组与对照组接种第1针、第2针乙肝疫苗后均未发现发热、体温波动与败血症等不良反应。结论:免疫后数年内,低出生体质量对乙肝疫苗抗体的持久性没有影响,也不影响乙肝疫苗抗体的安全性。     

国产甲型肝炎灭活疫苗用于儿童免疫效果研究

为了探讨国产甲型肝炎灭活疫苗在儿童中应用的免疫效果,选择2～15岁抗-HAV阴性健康易感儿童91名作为接种对象,采用0、6程序接种国产甲型肝炎灭活疫苗250U／剂,观察免疫后的局部反应和全身反应,并于全程免疫后一个月检测抗-HAV阳转率和抗体GMT。结果91例观察对象在初免和加强免疫后均未见即时副反应,只在8～72小时内出现轻微的一过性局部和全身反应。全程免疫后一个月抗-HAV阳转率为100％。抗体GMT为14 407mIU／ml。国产甲肝灭活疫苗在儿童中应用具有良好的安全性和免疫原性,采用0、6个月程序可获得高滴度抗体。     

甲、乙型肝炎联合疫苗接种恒河猴的初步观察

为了探索联合接种甲乙肝疫苗、实验性甲乙肝联合疫苗免疫恒河猴的安全性及免疫原性。实验中挑选了甲肝抗体阴性,乙肝两对半阴性,肝功能指标正常的健康恒河猴24只,随机分为10组。混合或分别接种,进行不同毒株的甲肝灭活疫苗与不同厂家的乙肝疫苗的配对效果比较。并接种了实验性甲乙肝联合疫苗;史克甲乙肝联合疫苗试验组。设甲肝单价灭活疫苗L8株、深圳乙肝单价疫苗作为对照。免疫方案0、4、24w。每只恒河猴接种lml。接种3d内,每天观察动物有无不良反应。接种1针和2针后4w内,每2w采集空腹静脉血,以后每4w采血1次检测抗HAV、抗HBs、ALT、AST直至40w。接种疫苗后4、8、24、28w穿刺肝组织做病理学检查。结果显示接种疫苗后3d内,所有恒河猴均无不良反应。ALT、AST无异常升高。4、8、24、28w肝组织无特殊病理改变。注射2针后4w,除3组外,其余各组抗HAV及抗HBs均阳转。3组抗HAV阳转时间迟至12w。全程免疫后12w(即40w),抗HAVGMT为258.75～37489.50mIU/ml;抗HBsGMT为8263.68～60008.064mIU/ml。甲乙肝疫苗联合免疫及实验性的甲乙肝联合疫苗接种恒河猴安全性及免疫原性均良好。     

Immune response to a new hepatitis B vaccine in healthcare workers who had not responded to standard vaccine: randomised double blind dose-response study.

OBJECTIVE: To evaluate the immunogenicity and reactogenicity of a new triple S recombinant hepatitis B vaccine in a cohort of healthy people in whom currently licensed hepatitis B vaccines had persistently not induced an immune response. DESIGN: Single centre, randomised, double blind, dose-response study. SETTING: Research vaccine evaluation centre at a teaching hospital. SUBJECTS: 100 healthcare workers aged 18-70 years with a history of failure to seroconvert after at least four doses of a licensed hepatitis B vaccine containing the S component. INTERVENTION: Each subject was randomly allocated two doses of 5, 10, 20, or 40 micrograms of a new hepatitis B vaccine two months apart. MAIN OUTCOME MEASURES: Immunogenicity of the four doses. Seroconversion and seroprotection were defined as an antibody tire > 10 IU/l and > 100 IU/l respectively against an international antibody standard. RESULTS: 69 subjects seroconverted after a single dose of the vaccine. After the booster vaccination one other subject seroconverted, bringing the overall seroconversion rate to 70%. Fifteen subjects given 5 micrograms of vaccine, 19 given 10 micrograms, 16 given 20 micrograms, and 20 given 40 micrograms seroconverted. Seroconversion rates in the four antigen dose groups were 60% (15/25), 76% (19/25), 64% (16/25), and 80% (20/25). After the booster dose there was no significant dose-response effect on the overall seroconversion rate, although the small sample size meant that a clinically important dose-response could not be ruled out. CONCLUSION: A single dose of 20 micrograms of the vaccine was as effective as two doses of either 40 micrograms or 20 micrograms of this vaccine formulation in terms of seroconversion, seroprotection, and geometric mean titres.     

Presence of maternal anti-HBs antibodies does not influence hepatitis B vaccine response in Brazilian neonates

Recently, it was suggested that maternal hepatitis B surface antigen antibodies (anti-HBs) acquired transplacentally could play a negative role in newborn infants' immune response to the hepatitis B vaccine. We compared the hepatitis B virus (HBV) vaccine response in infants born to mothers previously vaccinated against HBV (n = 91) to infants born to mothers who were not previously vaccinated (n = 221). All newborn infants received three intramuscular doses (10 μg) of HBV vaccine (Butang?) at 0,1 and six months. The first dose was administered at the maternity hospital within 12 h of birth. The geometric mean titres of anti-HBs were not different among newborn infants born to mothers who were anti-HBs-negative (492.7 mIU/mL) and anti-HBs-positive (578.7 mIU/mL) (p = 0.38). Eight infants did not respond to the HBV vaccine. Of them, six were born to anti-HBs-negative mothers and two were born to mothers with anti-HBs titres less than 50 mlU/mL. Despite the mother's anti-HBs-positive status, our data show a good immunogenicity of the Brazilian HBV recombinant vaccine in neonates.     

Intradermal vaccination of adults with three low doses (2 micrograms) of recombinant hepatitis B vaccine. II. Persistence of immunity and induction of immunologic memory

Of the 110 dentists who had presented seroconversion 50 days after the intradermal application of three 2 micrograms doses of the Belgian recombinant vaccine against hepatitis B (HB), administered eight years before at an interval of one month between the 1st and 2nd doses and of five months between the 2nd and 3rd doses, 51 were included for the assessment of the persistence of immunity. None of the dentists had hepatitis or had received HB vaccine during this period. All subjects were submitted to serological tests for the detection of the following markers of hepatitis B virus (HBV) infection: HBsAg, anti-HBc, HBeAg, anti-HBe, and anti-HBs, with no HBsAg, anti-HBc, HBeAg or anti-HBe being detected. A microparticle enzyme immunoassay (MEIA) revealed the presence of anti-HBs at protective titers (> or = 10 mIU/ml) in 42 dentists (82.4%), with the anti-HBs titer being higher than 100 mIU/ml in 36 of them (70.6%) (good responders), between 10 and 100 mIU/ml in 6 (11.8%) (poor responders), and lower than 10 mIU/ml in 9 (17.6%) (non-responders). According to clinical data and serological tests, none of the dentists had presented disease or latent HBV infection during the eight years following the first vaccination. A 2 micrograms booster dose was administered intradermally to eight dentists with anti-HBs titers lower than 10 mIU/ml (non-responders) and to six dentists with titers ranging from 10 to 100 mIU/ml (poor responders); the determination of anti-HBs one month later demonstrated the occurrence of seroconversion in the eight non-responders and an increase in anti-HBs titer in the six poor responders. In summary, the present results demonstrated the prolonged persistence of protection against HBV infection and the development of immunologic memory provided by vaccination against HB--with intradermal application of three 2 micrograms doses of the Belgian recombinant vaccine at 0, 1, and 6 months--carried out eight years before in 51 dentists.     

Seropositivity among Korean Young Adults Approximately 2 Years after a Single-Dose Vaccination against Hepatitis A Virus

We previously observed 80.7% seropositivity and a significant interaction between gender and hepatitis A virus (HAV) vaccine type (Havrix vs. Epaxal) on the seropositivity approximately 11 months after single-dose HAV vaccinations in Korean young adults. Our objective was to evaluate seropositivity approximately 2 years after a single-dose HAV vaccination and the influence of demographic characteristics on seropositivity, including the interaction between gender and vaccine type. Seronegative medical school students were randomly vaccinated with Havrix or Epaxal. Based on a total serum anti-HAV antibody titer cutoff of 20 IU/mL, 338 participants (76.0%) of the 445 vaccinees were seropositive 20–25 months after a single-dose HAV vaccination. The seropositive rates were similar after vaccination with Havrix (77.0%) and Epaxal (74.9%). Univariate analysis indicated that female (p = 0.052) and less obese (p < 0.001) participants had a higher seropositive rate, whereas other characteristics such as age, alcohol use, smoking history, vaccine type, and follow-up duration were not associated with seropositivity. Multivariate analysis indicated that women (p = 0.026) and participants with moderate alcohol use (p < 0.001) showed significantly higher seropositive rates than men and participants with no or low alcohol use, respectively. The seropositive rates after vaccination with Havrix and Epaxal were 70.9% and 67.5% in men and 87.7% and 91.3% in women, respectively (p for interaction = 0.304). Compared with the seropositive rate approximately 11 months after vaccination, the seropositive rate decreased substantially only in men in the Havrix group (11.0% points), and consequently, the interaction between gender and vaccine type disappeared while seropositivity remained high (87.7% and 91.3% in Havrix and Epaxal groups, respectively) among women approximately 2 years after vaccination. Further studies are needed to assess whether the seropositive rate would be maintained in all groups more than 2 years after a single-dose HAV vaccination.     

Immunogenicity of a DNA-recombinant hepatitis B vaccine (Engerix B) given at 3, 5 and 11 months of age with a new schedule suitable for mass vaccination programmes

Following the demonstration of a fully satisfactory immunogenic activity of a hepatitis B vaccination protocol consisting of three doses given at the 3rd and 5th months of age with a booster at 11, it was possible to administer this vaccine at the same times as the vaccinations for diphtheria, tetanus and polio which are mandatory in Italy at those ages. A field trial of this protocol in a hyperendemic area near Naples (prevalence of HBsAg about 14%) started on January 1987. The French vaccine, Hevac B, Pasteur, was used. At this time compliance is 99%, and fully satisfactory results both in terms of seroconversion rate (96.3%) and of mean anti-HBs titre (4,352 mIU/ml) two months after the booster dose have been obtained. In this paper we demonstrate that even for a new hepatitis B vaccine prepared by a DNA-recombinant technique (Engerix B, SK & F) recently introduced in Italy, the same schedule can be used. In fact two doses of this vaccine, the first given at three months of age and the second two months later, resulted in a 100% seroconversion rate and a mean anti-HBs titre of 560 mIU/ml. Two months after the booster given at 11 months of age the mean anti-HBs titre was 12,100.     

Isolation and immunizations with hepatitis A viral structural proteins: induction of antiprotein, antiviral, and neutralizing responses.

An immune affinity purification procedure for hepatitis A virus (HAV) was designed which yielded milligram quantities of the virus with greater than 95% purity. The major structural proteins VP-1, VP-2, and VP-3 were isolated from the purified virus by electroelution from sodium dodecyl sulfate-polyacrylamide gels and used to immunize Lewis rats (three to four doses, 10 to 15 micrograms per dose). The two Lewis rats immunized with VP-1 developed a strong antibody response to VP-1, as determined by Western blot analysis and immune precipitation of the denatured protein. These animals also developed a good antibody response to the whole virus, as demonstrated by a positive response in a competitive radioimmunoassay (HAV antibody test) and by precipitation of the whole virus. In addition, both animals developed a low titer neutralizing antibody to HAV, as demonstrated by an in vitro cell culture assay. While the two rats receiving VP-2 developed only minimal responses to the protein and to the virus by the same assays described above, one of the two developed a significant neutralizing antibody to HAV. The immunization of one Lewis rat with VP-3 induced a good antibody response to both denatured protein and the whole virus. This serum sample was also demonstrated to neutralize the viral infectivity. Finally, two rabbits that had received inoculations of sodium dodecyl sulfate and heat-disrupted HAV (containing 20 to 30 micrograms of each protein per dose) developed good antiprotein responses to all of the proteins and good antiviral responses, including a consistently significant neutralizing activity. The neutralizing antibody responses suggest that the structural proteins of HAV, or a portion of them, could provide the basis for a subunit vaccine for HAV.     

Focus: Vaccines: Sufficient Sleep,Time of Vaccination,and Vaccine Efficacy: A Systematic Review of the Current Evidence and a Proposal for COVID-19 Vaccination

Introduction: The emergence of the novel Coronavirus Disease 2019 (COVID-19) sparked an unprecedented effort to develop effective vaccines against the disease. Some factors may boost the vaccine efficacy, including sufficient sleep and morning vaccination. We aimed to conduct a rapid systematic review to summarize data regarding the association between sleep and time of vaccination with immunity after vaccination. Materials and Methods: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol, and three databases (PubMed, Web of Science, and Scopus) were searched up to March 12, 2022. Results: Eight studies were included regarding the sleep and immune response after vaccination, of them, five studies were on influenza, two studies on hepatitis A (HAV), and one study on hepatitis B. Accordingly, six out of eight studies found a positive correlation between sleep and immune response after vaccination. Regarding the time of vaccination, seven studies were eligible to be included (two studies on influenza, one study on HAV and influenza, one study on BCG, one study on hexavalent vaccine, and two studies on SARS-CoV-2 vaccine). Among them, four out of seven studies (including a study on SARS-CoV-2 inactivated vaccine) reported the priorities of morning versus afternoon vaccination regarding antibody production and immune response after vaccination. Conclusion: Taken together, cumulative evidence suggests that sufficient sleep and vaccination in the morning could enhance the immune response after vaccination. Hence, modulating the time of vaccination and sufficient sleep could a be simple and applicable strategy for increasing vaccine efficacy. Future studies could be performed with SARS-CoV-2 vaccines to investigate the effects of time of vaccination and sufficient sleep on COVID-19 vaccine efficacy.     

Transplacentally acquired maternal antibody against hepatitis B surface antigen in infants and its influence on the response to hepatitis B vaccine

Background

Passively acquired maternal antibodies in infants may inhibit active immune responses to vaccines. Whether maternal antibody against hepatitis B surface antigen (anti-HBs) in infants may influence the long-term immunogenicity of hepatitis B vaccine remains unknown.

Methodology/Principal Findings

Totally 338 pairs of mothers and children were enrolled. All infants were routinely vaccinated against hepatitis B based on 0-, 1- and 6-month schedule. We characterized the transplacental transfer of maternal anti-HBs, and compared anti-HBs response in children of mothers with or without anti-HBs. In a prospective observation, all 63 anti-HBs positive mothers transferred anti-HBs to their infants; 84.1% of the infants had higher anti-HBs concentrations than their mothers. One and half years after vaccination with three doses of hepatitis B vaccine, the positive rate and geometric mean concentration (GMC) of anti-HBs in 32 infants with maternal anti-HBs were comparable with those in 32 infants without maternal antibody (90.6% vs 87.5%, P = 0.688, and 74.5 vs 73.5 mIU/ml, P = 0.742, respectively). In a retrospective analysis, five and half years after vaccination with three doses vaccine, the positive rates of anti-HBs in 88 children of mothers with anti-HBs ≥1000 mIU/ml, 94 children of mothers with anti-HBs 10–999 mIU/ml, and 61 children of mothers with anti-HBs <10 mIU/ml were 72.7%, 69.2%, and 63.9% (P = 0.521), respectively; anti-HBs GMC in these three groups were 38.9, 43.9, and 31.7 mIU/ml (P = 0.726), respectively.

Conclusions/Significance

The data demonstrate that maternal anti-HBs in infants, even at high concentrations, does not inhibit the long-term immunogenicity of hepatitis B vaccine. Thus, current hepatitis B vaccination schedule for infants will be still effective in the future when most infants are positive for maternal anti-HBs due to the massive vaccination against hepatitis B.     

Observational Study of Vaccine Efficacy 24 Years after the Start of Hepatitis B Vaccination in Two Gambian Villages: No Need for a Booster Dose

Objectives

To determine the duration of protection from hepatitis B vaccine given in infancy and early childhood and asses risk factors for HBV infection and chronic infection.

Methods

In 1984 infant HBV vaccination was started in two Gambian villages. Cross sectional serological surveys have been undertaken every 4 years to determine vaccine efficacy. In the current survey 84.6% of 1508 eligible participants aged 1–28 years were tested. A spouse study was conducted in females (aged 14 years and above) and their male partners.

Results

Vaccine efficacy against chronic infection with hepatitis B virus was 95.1% (95% confidence interval 91.5% to 97.1%), which did not vary significantly between age groups or village. Efficacy against infection was 85.4% (82.7% to 87.7%), falling significantly with age. Concentrations of hepatitis B antibody fell exponentially with age varying according to peak response: 20 years after vaccination only 17.8% (95% CI 10.1–25.6) of persons with a low peak response (10–99 mIU/ml) had detectable HBs antibody compared to 27% (21.9% to 32.2%) of those with a high peak response (>999 mIU/ml). Time since vaccination and a low peak response were the strongest risk factors for HBV infections; males were more susceptible, marriage was not a significant risk for females. Hepatitis B DNA was not detected after infection, which tested soley core antibody positive. An undetectable peak antibody response of <10 mIU/ml and a mother who was hepatitis B e antigen positive were powerful risk factors for chronic infection.

Conclusions

Adolescents and young adults vaccinated in infancy are at increased risk of hepatitis B infection, but not chronic infection. Married women were not at increased risk. There is no compelling evidence for the use of a booster dose of HBV vaccine in The Gambia.     

Response to Booster Doses of Hepatitis B Vaccine among Young Adults Who Had Received Neonatal Vaccination

Background

Newborns who have received hepatitis B immunization in 1980s are now young adults joining healthcare disciplines. The need for booster, pre- and post-booster checks becomes a practical question.

Aims

The aim of this study is to refine the HBV vaccination policy for newly admitted students in the future.

Methods

A prospective study on medical and nursing school entrants to evaluate hepatitis B serostatus and the response to booster doses among young adults.

Findings

Among 212 students, 17–23-year-old, born after adoption of neonatal immunization, 2 (0.9%) were HBsAg positive, 40 (18.9%) were anti-HBs positive. At 1 month after a single-dose booster for anti-HBs-negative students, 14.5% had anti-HBs <10 mIU/mL, 29.0% and 56.5% were 10–100 and >100 mIU/mL, respectively. The anti-HBs levels were significantly higher for females than males (mean [SD]: 431 [418] vs. 246 [339] mIU/mL, P = 0.047). At 2–4 month after the third booster dose, 97.1% had anti-HBs >100 mIU/mL and 2.9% had 10–100 mIU/mL.

Conclusions

Pre-booster check is still worthwhile to identify carriers among newly recruited healthcare workers born after adoption of neonatal immunization. A 3-dose booster, rather than a single dose, is required for the majority to achieve an anti-HBs level >100 mIU/mL, as memory immunity has declined in a substantial proportion of individuals. Cost-effectiveness of post-booster check for anti-HBs is low and should be further evaluated based on contextual specific utilization of results.     

Hepatitis E virus DNA vaccine elicits immunologic memory in mice

Injection of an expression vector pJHEV containing hepatitis E virus (HEV) structural protein open reading frame 2 gene generates a strong antibody response in BALB/c mice that can bind to and agglutinate HEV. In this study, we tested for immunologic memory in immunized mice whose current levels of IgG to HEV were low or undetectable despite 3 doses of HEV DNA vaccine 18 months earlier. Mice previously vaccinated with vector alone were controls. All mice were administered a dose of HEV DNA vaccine to simulate an infectious challenge with HEV. The endpoint was IgG to HEV determined by ELISA. Ten days after the vaccine dose, 5 of 9 mice previously immunized with HEV DNA vaccine had a slight increase in IgG to HEV. By 40 days after the vaccine dose, the level of IgG to HEV had increased dramatically in all 9 mice (108-fold increase in geometric mean titer). In contrast, no control mice became seropositive. These results indicate that mice vaccinated with 3 doses of HEV DNA vaccine retain immunologic memory. In response to a small antigenic challenge delivered as DNA, possibly less than delivered by a human infective dose of virus, mice with memory were able to generate high levels of antibody in less time than the usual incubation period of hepatitis E. We speculate that this type of response could protect a human from overt disease.     

Comparison of modified HAVAB and ELISA for determination of vaccine-induced anti-HAV response

An inhibition ELISA was compared with a modification of the HAVAB assay for measuring antibodies induced by a killed HAV vaccine. GMT's expressed in mIU/ml were higher by ELISA than by modified HAVAB, especially after the first and second doses of vaccine but seroconversion rates were very similar and a good correlation was found between both assays. Because of its higher sensitivity and specificity, the ELISA assay was preferred to modified HAVAB for the evaluation of a Hepatitis A vaccine in human volunteers.     

Multicenter study on the immunogenicity and safety of two recombinant vaccines against hepatitis B

The immunogenicity and safety of a new recombinant hepatitis B vaccine from the Instituto Butantan (Butang) were evaluated in a multicenter, double-blind, prospective equivalence study in three centers in Brazil. Engerix B was the standard vaccine. A total of 3937 subjects were recruited and 2754 (70%) met all protocol criteria at the end of the study. All the subjects were considered healthy and denied having received hepatitis B vaccine before the study. Study subjects who adhered to the protocol were newborn infants (566), children 1 to 10 years old (484), adolescents from 11 to 19 years (740), adults from 20 to 30 years (568), and adults from 31 to 40 years (396). Vaccine was administered in three doses on the schedule 0, 1, and 6 months (newborn infants, adolescents, and adults) or 0, 1, and 7 months (children). Vaccine dose was intramuscular 10 microg (infants, children, and adolescents) or 20 microg (adults). Percent seroprotection (assumed when anti-HBs titers were > 10 mIU/ml) and geometric mean titer (mIU/ml) were: newborn infants, 93.7% and 351.1 (Butang) and 97.5% and 1530.6 (Engerix B); children, 100% and 3600.0 (Butang) and 97.7% and 2753.1 (Engerix B); adolescents, 95.1% and 746.3 (Butang) and 96% and 1284.3 (Engerix B); adults 20-30 years old, 91.8% and 453.5 (Butang) and 95.5% and 1369.0 (Engerix B); and adults 31-40 years old, 79.8% and 122.7 (Butang) and 92.4% and 686.2 (Engerix B). There were no severe adverse events following either vaccine. The study concluded that Butang was equivalent to Engerix B in children, and less immunogenic but acceptable for use in newborn infants, adolescents, and young adults.     

Is Obesity a Risk Factor for Vaccine Non-Responsiveness?

Understanding the link between vaccine immunogenicity and efficacy is currently a major focus in HIV research. Consequently, recent developments in the HIV-1 vaccine field have led to a closer look at immune responses to known efficacious vaccines. We undertook a study to explore clinical predictors of vaccine efficacy following recombinant hepatitis B (rHBV) vaccination in a cohort of HIV-uninfected, hepatitis B virus naïve women living in a peri-urban setting in Cape Town. Our aim was to define host biological risk factors associated with lack of vaccine uptake. We found a significant association (p=0.009) between body mass index (BMI) and lack of vaccine-specific IgG titre (<10mIU/mL). Obese individuals (BMI ≥ 30kg/m²) were significantly more likely to be non-responders following 2 rHBV vaccine doses (Adjusted Odds Ratio of 8.75; p=0.043). There was no observed association between vaccine responses and age, method of contraception or time from vaccination to antibody measurement. These data suggest that obesity-associated factors interfere with vaccine immunogenicity and possible efficacy.     

Changing Epidemiological Characteristics of Hepatitis A in Zhejiang Province,China: Increased Susceptibility in Adults

BackgroundHepatitis A is a common acute hepatitis caused by hepatitis A virus (HAV). Annually, it affects 1.4 million people worldwide. Between 1991 and 1994, HAV infections were highly endemic in Zhejiang Province (China), with 78,720 reported HAV infections per year. Hepatitis A vaccine came on the market in 1995 and was implemented for voluntary immunization. Since 2008, hepatitis A vaccine has been integrated into the national childhood routine immunization program.ObjectiveTo understand the current epidemiological profile of hepatitis A in Zhejiang Province since hepatitis A vaccine has been available for nearly two decades.MethodsThis study used the 2005–2014 National Notifiable Diseases Reporting System data to evaluate the incidence rate of notified hepatitis A cases in Zhejiang Province.ResultsThe overall trend of incidence rate of notified hepatitis A cases significantly decreased from 2005 to 2014 (P< 0.001). During the study period, the reported incidence rate in individuals aged ≤19 years declined to the historically lowest record in 2014. Compared with individuals aged ≤19 years, those aged ≥20 years showed the highest incidence rate (P< 0.001). Majority of HAV infected cases were Laborers, accounting for approximately 70% of reported cases.ConclusionsChildhood immunization strategy with hepatitis A vaccine seemed to be effective in decreasing notified hepatitis A incidence rate in individuals aged ≤19 years. Those aged ≥20 years were observed to be the most susceptible population. The vast majority of hepatitis A cases were notified among Laborers. Therefore, we strongly suggest that future preventive and control measures should focus more on adults, particularly Laborers, in addition to the current childhood hepatitis A vaccination programme.     

Comparison of one- and two-dose regimens of influenza vaccine for elderly men.

In November and December 1984, 102 male residents of a long-term care facility (mean age 74.6 [extremes 59 and 97] years) received 0.5 ml of trivalent inactivated whole-virion influenza vaccine, containing 15 micrograms of the hemagglutinin of each of A/Philippines/2/82 (H3N2), A/Chile/83 (H1N1) and B/USSR/83. A second dose of the vaccine was administered to a subgroup of 55 randomly chosen subjects 8 weeks later. Serum samples were collected from all the subjects before and 4, 8, 12 and 16 weeks after administration of the first dose and were assayed for hemagglutinin-inhibiting (HAI) antibody to each of the three antigens. At 8 weeks there were significant increases (p less than 0.05) in the geometric mean titre of antibody and in the proportion of subjects with HAI antibody titres of 1:40 or more (except to the B/USSR antigen) in both groups. There were no differences between the groups at 8 weeks or at 16 weeks (8 weeks after administration of the second dose of vaccine) in the frequency of seroconversion, the geometric mean titre or the proportion of subjects with HAI antibody titres of 1:40 or more. Overall, 60%, 32% and 13% of the 102 subjects had titres of 1:40 or more to the A/Philippines, A/Chile and B/USSR antigens respectively at 16 weeks. The results suggest that a second dose of influenza vaccine given 8 weeks after the first does not enhance the immune response in elderly men and that a substantial proportion of this population remains unprotected against infection (having HAI antibody titres of less than 1:40) during the influenza season.     

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.