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Booster Dose (booster + dose)
Selected AbstractsWaning immunity to plasma-derived hepatitis B vaccine and the need for boosters 15 years after neonatal vaccinationHEPATOLOGY, Issue 6 2004Chun-Yi Lu Neonatal immunization with hepatitis B (HB) vaccine is highly effective; however, more needs to be learned about the duration of protection and indications for boosters. We measured antibody to HB core antigen (anti-HBc), HB surface antigen (HBsAg), and pre- and postbooster titers of HBsAg antibody (anti-HBs) 15 years after primary neonatal immunization with plasma-derived HB vaccines in 2 cohorts of 15-year-old children. Group A consisted of 78 children who were born to HB e antigen,positive HBsAg carrier mothers and had developed protective levels of anti-HBs antibodies (,10 mIU/mL) following HB immunization. Group B consisted of 113 apparently healthy children whose anti-HBs titers after vaccination were unknown. Anti-HBs was undetectable (antibody titer <10 mIU/mL) in 29.9% in group A and 62.4% in group B (P < .001). Anti-HBc was detected in 33.3 % in group A and 4.4 % in group B (P < .001). After a single booster dose of HB vaccine, 2.7% in group A and 3.3% in group B remained anti-HBs,negative. A blunted serological response was noted in approximately 20% in both groups. One HBsAg carrier was detected in group A (1.3%) and 4 in group B (3.5%). Fifteen years after neonatal immunization with plasma-derived HB vaccine, a large proportion of children exhibited waning immunity. This poses the risk of breakthrough infection. A single booster augmented the serological response to the vaccine in most but not all subjects. In conclusion, our findings suggest that one or more booster immunizations are needed in seronegative subjects by at least 15 years following neonatal immunization with plasma-derived HB vaccine. (HEPATOLOGY 2004;40:1415,1420.) [source] Hepatitis B vaccination is effective for babies weighing less than 1800 gJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 5 2006Wee-Bin Lian Aim: This trial studied the effectiveness of early hepatitis B (HepB) immunisation in babies weighing less than 1800 grams, born of HepB surface-antigen-negative mothers. Methods: The first vaccine dose was given once clinical stability was achieved, with second and third doses given 1 and 6 months later, respectively. HepB serology, done using Abbott ElA (phase 1) and Abbott Axsym (phase 2) before and after June 2001, respectively, was checked at birth (Sero1), prior to (Sero2) and 6 months after (Sero3) the third dose. A booster dose was recommended when Sero3 showed a non-immune status (<10 mIU/mL). Results: Median birth weight and gestational age (n = 118) were 1295 [range 475, 1780] g and 31 [range 24, 37] completed weeks, respectively. Sero1 (median age of 4 [range 1, 34] days) showed 64% (n = 113) to be non-immune. The first dose of vaccine was administered at a median weight of 1268 [range 530, 1790] g, median age of 6 [range 1,63] days and median post-menstrual age of 32 [range 24,37] completed weeks. Sero2 (median age of 179 [range 112,260] days), for 110 babies (93.2%) showed immunity in 48.2% (median titres , Phase 1: 26 [range 10, 150] mIU/mL; Phase 2: 34 [range 10, 1000] mIU/mL). Sero3 revealed seroprotection in 77.8% (median titres , Phase 1: 102 [range 12, 150] mIU/mL; Phase 2: 162 [range 16, 1000] mIU/mL). The more mature the bady at time of first dose, the more likely he is to achieve seroprotection (85% amongst those administered at and beyond 33 weeks; 91% among those administered at and beyond Day 10 at Sero3). Conclusions: Early HepB immunisation in infants <1800 g can be safely recommended, with booster doses necessary at 1 year for some infants. [source] Vaccination against hepatitis B in liver transplant recipients: Pilot analysis of cellular immune response shows evidence of HBsAg-specific regulatory T cellsLIVER TRANSPLANTATION, Issue 3 2007Tanja Bauer After liver transplantation for hepatitis-B-related diseases, patients currently receive lifelong treatment with hepatitis B immunoglobulin to prevent endogenous reinfection with hepatitis B virus (HBV). Active immunization with hepatitis B vaccine would be a preferable alternative; however, most attempts to immunize these patients with standard vaccine have failed. A recent study with a new adjuvanted hepatitis B vaccine was exceptionally successful, leading to a high-titered long-lasting antibody response in 80% of all vaccinees. To identify the immunological mechanisms behind these unexpected results, the successfully vaccinated participants were tested for hepatitis B surface antigen (HBsAg)-specific T and B cells, and their cellular responses to revaccination with conventional vaccine were studied. HBsAg-specific CD4+ T lymphocytes could be detected in 13 of 16 patients after immunization with the new vaccine. Unexpectedly, these T cells produced almost exclusively interleukin (IL)-10 and had a CD4+/CD25+ phenotype. They were functionally active, suppressing cytokine secretion in HBsAg-specific (Th1) cells, thus representing antigen-specific regulatory T cells (TReg). Following a booster dose with conventional vaccine 22-31 months after completion of the initial vaccination series, the T-cell pattern in the revaccinated individuals changed substantially: 7 days after revaccination 9 of 11 individuals showed a switch to a Th1-type immune response with HBsAg-specific T cells secreting IL-2, interferon gamma and tumor necrosis factor alpha as observed in healthy controls. Four weeks after the booster, 4 patients still showed a Th1-type cytokine pattern, whereas in 5 patients only IL-10-secreting cells were detectable. After 1 year, in 3 of 4 revaccinated individuals only IL-10-secreting cells could be found, whereas the specific T cells of the fourth patient still showed a Th1-type of response. HBsAg-specific TReg cells could be demonstrated in HBV-positive liver transplant recipients successfully immunized with a new adjuvanted vaccine. Revaccination led to immediate disappearance of the these cells and the appearance of HBsAg-specific T cells with a Th1-type cytokine profile, which in most cases were replaced by the IL-10-secreting regulatory cells during the following months. The specific induction of TReg cells could contribute to the poor response of liver transplant recipients to conventional vaccine. In conclusion,, for successful vaccination of these patients, a vaccine with a strong inhibitory effect on TReg cells would be desirable. Liver Transpl 13:434,442, 2007. © 2007 AASLD. [source] Humoral immunity to diphtheria, tetanus, measles, and hemophilus influenzae type b in children with acute lymphoblastic leukemia and response to re-vaccinationPEDIATRIC BLOOD & CANCER, Issue 6 2009Emine Zengin Abstract Objective Loss of immunity to previous vaccination and timing of re-vaccination in children receiving chemotherapy remains controversial. The aim of this study was to investigate the immunity to vaccine preventable diseases in children with acute lymphoblastic leukemia (ALL). Procedure Sixty-one patients with ALL and 13 healthy siblings were enrolled. Three study groups included newly diagnosed patients (group 1), patients on maintenance chemotherapy (group 2), and patients that completed chemotherapy (group 3). Blood samples for baseline antibody titers were obtained from all the patients and controls. Patients in group 2 were vaccinated with diphtheria, tetanus, and hemophilus influenzae type b (Hib). Patients in group 3 and controls received the measles vaccine in addition to all the above vaccines. In groups 2 and 3, post-vaccination antibody titers were also obtained. Results Patients and controls had no Hib vaccine during primary vaccination. After chemotherapy median antibody levels against diphtheria, tetanus, measles, and Hib were decreased but tetanus antibodies were still at the protective levels. Proportions of the patients with protective levels were 11.1%, 83.3%, 16.7%, and 16.7% for diphtheria, tetanus, Hib, and measles, respectively. Vaccination achieved protective antibody levels in 81%, 100%, 89.5%, and 70% of the patients for diphtheria, tetanus, Hib, and measles, respectively. Vaccine responses during maintenance were also satisfying. Conclusion We recommend re-vaccination after 3 months of cessation of chemotherapy. Administration of Hib vaccine may be beneficial after the first 3 months of maintenance chemotherapy especially in children with no primary vaccination followed by a second booster dose after cessation of therapy to increase immunity. Pediatr Blood Cancer 2009;53:967,972. © 2009 Wiley-Liss, Inc. [source] Coverage of recommended vaccines in children at 7,8 years of age in Flanders, BelgiumACTA PAEDIATRICA, Issue 8 2009Heidi Theeten Abstract Aim:, Evaluation of the coverage of primary diphtheria-tetanus-pertussis (DTP), poliomyelitis, hepatitis B (HBV) and measles-mumps-rubella (MMR) vaccine doses recommended before the age of 18 months in 7-year-old school children in Flanders, Belgium. Meningococcal serogroup C and DT-polio vaccines offered respectively as catch-up and booster vaccinations were also evaluated. Methods:, Parents of 792 children born in Flanders in 1997 and selected by cluster sampling were interviewed at home in 2005. Vaccination data since infancy were collected retrospectively from vaccination documents and school health records. Results:, Coverage rates were 88.0% for the first dose of MMR, and 72.0%, 84.2% and 91.4% for the recommended HBV, DTP and poliomyelitis primary vaccine doses, respectively. These rates included catch-up of missed infant MMR (4.9%) and HBV (6.4%) vaccinations. In addition, 88.3% of the target group received the DT-polio booster dose recommended at 6 years of age and 83.1% a meningococcal C vaccine dose. Preventive public health services as well as private physicians were involved to a varying extent. A lower socioeconomic status of the family was associated with a higher risk of nonvaccination. Conclusion:, Vaccinators in Flanders reach children relatively well during infancy and at school age, but catch-up of missed infant vaccine doses, especially MMR, should be optimized. [source] Haemophilus influenzae type b conjugate vaccinesIMMUNOLOGY, Issue 2 2004Dominic F. Kelly Summary Haemophilus influenzae type b (Hib) is one of the leading causes of invasive bacterial infection in young children worldwide. During childhood, acquisition of antibody directed against the polysaccharide capsule of the organism, presumably as a result of asymptomatic carriage, confers protection and disease is much less common after the age of 4 years. Like other polysaccharides, the polyribosyl ribitol phosphate (PRP) of the Hib capsule is a T-independent antigen and not immunogenic when administered as a vaccine in infancy. Because the highest rates of disease occur in the first 2 years of life, efficacious Hib vaccines have been designed by covalently linking the PRP capsule to a carrier protein that recruits T-cell help for the polysaccharide immune response and induces anti-PRP antibody production even in the first 6 months of life. Introduction of Hib protein,polysaccharide conjugate vaccines into many industrialized countries over the past 15 years has resulted in the virtual elimination of invasive Hib disease. However, despite the success of the vaccine programme several factors may interfere with the effectiveness of the vaccine in the routine programme, as observed in the UK recently. Such factors may include interference with other concomitant vaccines, waning immunity in the absence of booster doses of vaccine, and reduced natural boosting as a result of decreased transmission of the organism. However, the burden of disease remains highest in resource-poor countries and urgent efforts are needed to provide the benefits of this vaccine for children living in regions where it cannot be used for economic and logistical reasons. [source] Antibodies to surface epitopes of the carbohydrate larval antigen CarLA are associated with passive protection in strongylid nematode challenge infectionsPARASITE IMMUNOLOGY, Issue 11-12 2008G. B. L. HARRISON SUMMARY Sheep were immunized by multiple truncated infections with the gastrointestinal nematodes Trichostrongylus colubriformis, Haemonchus contortus and Teladorsagia circumcincta. Three infections with T. colubriformis of 14 days plus five booster doses of L3 stimulated highly effective protection against challenge (99%). Three infections of 14 days plus three booster doses with H. contortus also resulted in significant protection against challenge infection (87%), but the same procedure was not effective for T. circumcincta. Antibodies derived from gastrointestinal mucus of these immunized sheep were tested for their ability to reduce worm burden following injection of antibody-coated exsheathed larvae into the abomasum (H. contortus and T. circumcincta) or duodenum (T. colubriformis) of nematode-naïve sheep in a passive immunity test. The IgG fraction from the mucus of immunized sheep reduced worm burdens by 62%, 76% and 91% in three tests with T. colubriformis but was not effective for either of the abomasal dwelling nematodes H. contortus and T. circumcincta. Antibodies in immune mucus predominantly recognized two larval surface antigens on immunoblots of L3 extract, a high MW surface glycoprotein and the carbohydrate larval antigen (CarLA). Antibodies raised against purified T. colubriformis glycoprotein Tc-120 and CarLA were tested in the passive immunity model and it was found that only the antibody against CarLA resulted in a significant reduction of infection (87%). The protective anti-CarLA antibodies strongly recognized the surface of living T. colubriformis L3. Antibodies from abomasal mucus of sheep immunized by H. contortus and T. circumcincta infections reacted weakly with CarLA and the larval surface and did not reduce worm counts in a passive immunity test. The results provide further evidence that the larval surface carbohydrate antigen CarLA has potential as a mucosal immunogen for a strongylid nematode vaccine. [source] | |||||||||||||||||||