SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Infections in children in day care are common but can be limited by several measures which include education of providers and staff in standards of hygiene, maintenance of basic techniques of infection control, appropriate use of the physical facilities of the day care facility and maintenance of recommended immunization schedules of children and staff.
A study was undertaken on 500 children under the age of 5 years belonging to a low income group. All were attending the paediatrics outpatient department of a large teaching hospital in New Delhi, India. Only 25% were found to have received complete primary immunization as per the National Immunization Schedule (bacille Calmette-Guérin at birth, three doses of diphtheria, pertussis and tetanus and oral poliovirus vaccine at 6,10 and 14 weeks and measles vaccine at 9 months). The major reasons for non-immunization of the children were: migration to a native village (26.4%); domestic problems (9.6%); the immunization centre was located too far from their home (9.6%); and the child was unwell when the vaccination was due (9%). Twelve per cent of mothers could not give any reason for non-immunization. In addition to the migration of children to rural areas, the other significant finding was an indirect effect of intensive OPV administration as part of polio eradication initiative. The lack of awareness and fear of side effects constituted a small minority of reasons for non-immunization.
Rabies vaccine derived from human diploid cells (Wyeth, Merieux) and the duck embryo vaccine Lyssavac Berna are prepared from beta-propiolactone-inactivated Pitman-Moore vaccine virus strain. A group of 113 seronegative veterinary students was vaccinated with Lyssavac Berna according to the 4-dose immunization schedule recommended by WHO. Seroconversion was obtained in all test persons. The vaccine was very well tolerated. In agreement with the literature we also found a relatively fast decline in the neutralizing antibody titer after this immunization procedure. However, a booster injection after one year resulted in an antibody rise with titer values comparable with or higher than those obtained after the primary vaccination course. An annual single revaccination dose should be sufficient to protect people at risk.
The availability of efficacious hepatitis A vaccines should greatly facilitate the prevention of hepatitis A virus (HAV) infection. Groups at high risk of HAV infection have been identified from epidemiological studies and include both children and adults. While certain high-risk adults, such as travellers, could be a convenient target for vaccination, selective immunization of high-risk adults would not be expected to lower the overall rates of infection in most countries. Because a significant proportion of HAV infections occur in children, the eventual objective should be the integration of hepatitis A vaccine into routine childhood immunization schedules. This would reduce disease incidence by preventing infections in children and by preventing infections in adults that are acquired from children. The cyclical patterns of hepatitis A observed in many countries are related to levels of immunity in the population. The elimination of the susceptibility of a population to HAV infection through immunization could eliminate this well known human disease. This suggests that eradication of HAV infection should be attainable with effective hepatitis A vaccines.
Optimal influenza immunization of individuals with malignancy and other immunodeficient states requires and understanding of responses to currently recommended regimens. Children with acute lymphocytic leukemia and other malignancies between three and 17 years of age were immunized with bivalent influenza vaccine containing A/New Jersey/76 and A/Victoria/75. Folowing a two-dose immunization schedule, only 37% (25468) on cancer chemotherapy seroconverted to a hemagglutination inhibition titer greater than or equal to 20 for A/NJ/76; the seroconversion rate in those not on chemotherapy was 92% (68/74, P less than 0.001). The immune response to the A/Vic/75 antigen was also related to a history of recent chemotherapy. There was no correlation between the immune response and the peripheral white blood cell count except at counts less than or equal to 1,000. The optimum time to immunize children with malignancies is when they have been off chemotherapy for one month and have peripheral white blood counts greater than 1,000.
The progress in vaccines for Haemophilus influenzae type b infection is followed; it is the disadvantages of pure polysaccharide vaccines that have stimulated the development of the present generation of polysaccharide-protein conjugated vaccines. From extensive clinical trials it is apparent that these are very effective in preventing disease in children. Conjugated haemophilus vaccines were introduced into the routine immunization schedules in the UK in Autumn 1992. Meningococcal A and C polysaccharide vaccines, effective for epidemic disease, are only now being developed in a protein conjugated form with the prospect of protecting young children and producing durable immunity. Group B outer membrane-based meningococcal vaccines produce only a low degree of protection and much further work is needed before even the optimum vaccine constituents of this organism can be identified. Vaccines to replace multivalent pneumococcal polysaccharide mixtures are only in the very earliest stages of development.
A comparison has been made of the interactions between passively transferred and actively acquired immunity in regulating populations of Taenia hydatigena and T. ovis. When ewes were grazed prior to parturition under a high infection pressure, immunity was transferred to their offspring for up to 8 weeks. A qualitative difference between the species was the destruction of larval T. ovis prior to their establishment ('pre-encystment immunity') and that of T. hydatigena after they had become established ('post-encystment immunity') in the challenged lambs. The major difference in terms of population regulation between the two parasites was that infection occurred with T. hydatigena but not with T. ovis in those lambs reared from birth for 16 weeks under high infection pressure. Passive, like active immunity, is a density-dependent constraint. It plays an important role in the population regulation of T. ovis, but not of T. hydatigena. This is discussed in terms of transmission in the natural environment, an hypothesis on humoral protection and the need to elucidate pathways of protection when immunization schedules are being evaluated for controlling the taeniid zoonoses.
Physicians counseling patients who are planning major travels should make sure that baseline immunizations (diphtheria-tetanus-pertussis, polio, measles, rubella) and any necessary boosters are current. In addition, several other immunizations may be warranted (yellow fever, typhoid, and cholera), depending on destination(s) and itinerary, and prophylaxis for malaria may be advisable. As worldwide requirements for immunization do change, the physician should verify current requirements before planning an immunization schedule for a particular patient.
To characterize factors of importance for the occurrence of acute rejection as well as study the impact of these episodes on long-term renal survival and function, a total of 819 acute rejection episodes were studied in 951 primary cadaveric donor kidney recipients (CD) and in 396 primary living donor kidney recipients (LD). The patients were treated by three immunosuppressive schedules, namely, CsA given in a high dose, a medium dose, or a low dose. Additionally, all patients received PRED and patients in the low-dose group received AZA. The incidence of acute rejection was higher and occurred earlier after transplantation in the CsA medium dose and low dose groups than in the CsA high dose group (P < 0.05 and P < 0.01, respectively). Although the incidence of first acute rejection was similar in CD and LD patients, 59.1% vs. 60.6%, it was successfully reversed by antirejection treatment in a higher percentage in LD patients. The estimated graft half-life was shorter in patients who had acute rejection episodes than those who did not, 6.6 years vs. 12.5 years in CD patients (P < 0.0001). Renal function at 1-5 years after transplantation was stable, but significantly poorer in CD patients who had experienced acute rejection than in patients who had not, with the mean creatinine clearance rates in the ranges 45-47 vs. 54-60 ml/min in the other groups (P < 0.0001). In a stepwise Cox regression analysis in CD recipients, risk factors for acute rejection were CsA (low dose) treatment schedule, immunization as displayed by presence of panel-reactive antibodies and positive B cell cross-match, young recipient age, disease of diabetes mellitus, and HLA-DR mismatching. In LD recipients, the corresponding risk factors were treatment schedule, young recipient, HLA mismatching, and transplantation from parent to child. Thus, the study has demonstrated some factors of importance for acute rejection episodes in CsA-treated patients as well as showing the detrimental effect of these episodes on long-term graft survival and renal function. These results suggest that a primary aim of future treatment strategies should be to reduce the incidence of these episodes.
BACKGROUND: Prostate-specific membrane antigen (PSMA) is a well characterized prostate-specific tumor associated antigen. Its expression is elevated in prostate carcinoma, particularly in metastatic and recurrent lesions. These observations suggest that PSMA can be used as immune target to induce tumor cell-specific recognition by the host and, consequently tumor rejection. We utilized a DNA-based vaccine to specifically enhance PSMA expression. An immune modulator, such as CpG oligodeoxynucleotides which promote Th1-type immune responses was combined to increase the efficacy of tumor recognition and elimination. METHODS: A eukaryotic expression plasmid pCDNA3.1-PSMA encoding full-length PSMA was constructed. C57BL/6 mice were immunized with endotoxin-free pCDNA3.1-PSMA alone or in combination with CpG oligodeoxynucleotides by intramuscular injection. After 4 immunizations, PSMA specific antibodies and cytotoxic T lymphocyte reactivity were measured. Immunized C57BL/6 mice were also challenged subcutaneously with B16 cells transfected with PSMA to evaluate suppression of tumor growth. RESULTS: Vaccine-specific cytotoxic T lymphocytes reactive with B16 cells expressing PSMA could be induced with this treatment schedule. Immune protection was observed in vaccinated mice as indicated by increased tumor growth in the control group (100%) compared with the groups vaccinated with DNA alone (66.7%) or DNA plus CpG oligodeoxynucleotides (50%) respectively. Average tumor volume was smaller in vaccinated groups and tumor-free survival time was prolonged by the vaccination. CONCLUSION: The current findings suggest that specific anti-tumor immune response can be induced by DNA vaccines expressing PSMA. In addition, the suppression of in vivo growth of tumor cells expressing PSMA was augmented by CpG oligodeoxynucleotides. This strategy may provide a new venue for the treatment of carcinoma of prostate after failure of standard therapy.
While worldwide efforts to develop an effective HIV-1 vaccine are underway, the virus continues to spread, particularly in developing countries where the delivery of antiviral therapies presents formidable challenges. Vaccine research has largely focused on three general aspects: vectors, adjuvants, and immunization schedules. Our group favor the use of computational methods to design potential immunogens that capture the genetic and biological features of circulating viruses. These methods allow researchers to predict, in silico, the presence of potential glycosylation sites, humoral immune responses, and epitope coverage. This review shall compare three computational approaches for immunogen design: the consensus sequence, which has at each site the modal nucleotide or amino acid residue across a sequence alignment; the most recent common ancestor, the sequence estimated at the basal node of the clades seen in the HIV-1 phylogeny; and the center of tree method, which minimizes the evolutionary distance to all sequences in the data set.
The recommended childhood immunization schedule is complex, with multiple doses of vaccines required to complete the series. For a variety of reasons, a single manufacturer's product may not be available for all of the doses needed. In addition, combination products may become available, allowing for fewer injections to be administered but resulting in a change of vaccine components. To ensure the timely immunization of children and to avoid missed opportunities to vaccinate, it is important to be familiar with data documenting the interchangeability of vaccines. Although clear evidence is available to demonstrate the interchangeability of some vaccines (i.e., hepatitis B vaccines and Haemophilus influenzae type b vaccines), it is more difficult to evaluate the interchangeability of others (i.e., diphtheria-tetanus-acellular pertussis [DTaP] vaccines). Limited data support the interchangeability of some DTaP products when necessary. This article presents the safety and immunogenicity data for immunization regimens that use vaccines from different manufacturers.
Lactation in sheep and mice was associated with a marked increase in susceptibility to newly acquired infection with Haemonchus contortus and Nematospiroides dubius, respectively. In sheep this increased susceptibility to infection with H. contortus occurred in late pregnancy and during lactation and was seen when the ewes were infected with both a single large dose of infective larvae and a "trickle" infection of 200 and 400 infective larvae of H. contortus given weekly for 14 weeks. Nonlactating ewes whose lactation had been terminated were able to reject the parasites which had been acquired in late pregnancy. A relaxation in the protective immune response was evident in immunized mice infected during lactation with N. dubius. However, despite this periparturient relaxation of immunity mice were capable of inducing a marked passive transfer of immunity to their offspring. Thus, neonatal mice born of mothers one or two months after the end of the immunizing schedule were protected against infection with N. dubius at 12 or 20 days of age.
Pertussis is an epidemic disease caused by Bordetella pertussis and also to a lesser extent by Bordetella parapertussis. Classical illness lasts 4-8 weeks and is characterized by paroxysms of coughing with posttussive vomiting and whooping; however, 47.4% of primary infections last 4 weeks or less. Whole cell pertussis vaccines are generally highly efficacious. All whole cell vaccines are reactogenic, causing fever and local reactions in many vaccinees. In the past, these vaccines were thought to cause infant deaths and brain damage. However, several large epidemiologic studies indicate that whole cell vaccines do not cause infant deaths or neurologic disease. Recent studies indicate that neither immunization nor infection give long-term immunity. As a result, B. pertussis infections are endemic in adult populations. The future control of B. pertussis will require immunization schedules with new acellular vaccines that include booster doses in older children and adults.
OBJECTIVE: To provide an overview of childhood immunizations with emphasis in new recommendations, as well as recent vaccine developments and special populations. DATA SOURCES: English language literature identified via a MEDLINE search. Additional references were obtained from cited references. STUDY SELECTION AND DATA EXTRACTION: Original articles, reviews, and official publications were used to obtain the most accurate data on safety and efficacy of available pediatric vaccines, as well as current recommendations for their use. DATA SYNTHESIS: Immunizations have been an area of vigorous research for several years. New vaccines have been developed by improving older products to maximize immunogenicity and minimize adverse effects. Some of these novel vaccines, like the Haemophilus influenzae type b conjugate vaccines (HibCV), have already contributed significantly to the prevention of diseases in childhood. New recommendations have been issued to help speed this process. Adverse effects of routine immunizations are generally mild and transient. CONCLUSIONS: The development of new effective and safe vaccines for children is an important step in the global eradication of contagious diseases. A new generation of combination vaccines has started with the combination of the diphtheria-tetanus-pertussis vaccine and HibCV. Some other combined products are yet to come that would eventually make immunization schedules more cost-effective and improve compliance rates. Our colleagues in the community and in the ambulatory care setting must actively participate in the implementation of vaccination programs and provide education to parents regarding all aspects of the immunization process.
OBJECTIVES: To determine OPV coverage impact of the 2001 national immunization day in different geographic regions and its association with the Unsatisified Basic Needs Index (NBI), forced displacement and armed conflict. METHODS: This is an analytical ecological study of multiple groups using multilevel observation units such as region, department, province and municipality. A bivariate analysis with difference between proportions between paired samples (McNemar test), estimation of OR, lineal regression and relative risk determination (Morgenstern) was carried out. In addition, protected and susceptible populations in each observation unit were compared. RESULTS: The OPV3 coverage increase between October and December, 2001, was 15 to 19% (p<0.05) and the final coverage was 78-84%. The provincial analysis demonstrated a 25.8% of total population with OPV3 coverage greater than 95%. An increase of 4 to 7 departments and 281 to 328 cities with at least 95% coverage (p<0.05) was observed. The risk of having incomplete immunization schedules decreased in armed conflict zones, remained stable in areas with high NBI and increased in areas with a high proportion of displaced families. The booster goal of the OPV had reached a median of 61%. CONCLUSIONS: The national immunization day diminished immunization access barriers for children under 5 years. The analysis of different geographic units controls the effect of the unknown population denominators. The ecological studies improved routine data analysis.
A retrospective study on an immunization programme was carried out in the Well Baby Clinic, Child Health Department, School of Medicine, University of North Sumatera, Dr. Pirngadi Hospital, Medan from January to December 1986. Of the 5951 total visits (an average of 495 visits each month) 3960 were primary and 1991 secondary visits. Most were first children in the family (39.9%) of which 37.6% were from one child families. Of 3275 live births 57.6% were immunized with BCG immediately after birth. The average BCG immunization visits to the Well Baby Clinic was 17 visits/day. When compared with DPT I and polio I visits we recorded a decrease of 27.1% for DPT II; 47.9% DPT III; 27.4% polio II; and 49.1% polio III respectively. Daily coverage of measles immunization visits was 4.6%. Complete immunization among the under-one-year-old children was 5.7% of which 44.9% were of the 9-12 months old group. The simultaneous immunization (BCG, DPT, polio, measles) comprised 0.5% of all visits. 4.1% of all visits were not immunized of which 36.5% was because they were beyond the immunization schedule.
Potentiation of the host immune system has been considered, in addition to non-immunological measures as a means of preventing the development of dental caries. Because specific antibodies in the oral cavity are derived from two sources--the salivary glands that produce secretory IgA, and the general circulation that provides IgG antibodies--immunization efforts in various experimental models have been aimed at stimulating either of these compartments. Streptococcus mutans, the principal cariogenic microorganism, and various cell wall components and extracellular enzymes have been used as antigens. In experimental animals, systemic or oral routes of immunization have induced protective IgG or IgA antibodies respectively, but the mechanisms of protection have not been clearly established. The possibility of stimulating a generalized secretory immune response by oral ingestion of antigens may have advantages for the induction of protective antibodies in humans, because parenteral immunization routes may not be readily acceptable for reasons discussed in this review. Nevertheless, further experimental work is required to select appropriate antigens, and to determine optimal doses and immunization schedules for inducing antibodies at an age that is critical in the development of dental caries.