Reticencia vacunal: análisis del discurso de madres y padres con rechazo total o parcial a las vacunas

Objective

To analyse and understand vaccination hesitancy discourses, particularly those of people who have decided not to vaccinate their sons and daughters.

Immunogenicity and safety of a novel yeast Hansenula polymorpha-derived recombinant Hepatitis B candidate vaccine in healthy adolescents and adults aged 10–45 years

The aim was to determine whether the immunogenicity of an investigational hepatitis B vaccine (spHB) is at least as high as that of a licensed control vaccine, Engerix B^®, and to evaluate its safety before inclusion in new pediatric combination vaccines. Two randomized, controlled, blind-observer, Phase 3 trials were performed: one in Argentina (344 participants aged 10–15 years, 10 μg HBsAg/dose) and one in Uruguay (344 participants aged 16–45 years, 20 μg HBsAg/dose). Both vaccines were given in a 0, 1, 6 month schedule to all participants with a baseline anti-Hep B antibody titer <0.6 mIU/mL. Antibody titers were measured pre-dose 1, 1 month after dose 2, pre-dose 3, and 1 month after dose 3. Statistical non-inferiority analyses were performed on seroprotection rates (SP) post-dose 3 (% with anti-Hep B titers ≥10 mIU/mL; delta non-inferiority limit of −10%). In both studies, SP for the spHB vaccine was 100% and the spHB vaccine was non-inferior in terms of SP to the licensed control vaccine. GMTs post-dose 3 were approximately 1.8- and 4.1-fold higher for spHB in the 10–15 year and 16–45 year age groups, respectively. Reactogenicity was low for each vaccine, after each dose. This highly immunogenic hepatitis B candidate vaccine was selected for further investigation as a component of new pediatric combination vaccines.     

Characteristics of antibody responses in tick-borne encephalitis vaccination breakthroughs

Tick-borne encephalitis (TBE) virus is an important human pathogenic flavivirus that is endemic in Europe and Asia. The disease can be effectively prevented by inactivated vaccines and vaccination breakthroughs (VBTs) are rare. We investigated the characteristics of antibody responses in such VBTs in comparison to those in unvaccinated TBE patients. In contrast to the unvaccinated controls, most of the VBTs displayed a delayed IgM antibody response and had high avidity and strongly neutralizing antibodies already in the first sample taken upon hospitalization. The antibody profile of these patients therefore had the characteristics of an anamnestic immune response. In the VBTs analyzed, immunological priming and memory were apparently not sufficient or fast enough to prevent the disease.     

A群多糖脑膜炎菌苗最适免疫剂量的研究

近些年来对Ａ群多糖脑膜炎菌苗最适免疫剂量进行了一系列现场流行病学及血清学效果的对比研究。首先肯定了我国生产的菌苗与法国Ｍｅｒｉｅｕｘ研究所生产的苗苗在人体接种后观察一年内具有同等杀菌抗体反应。以后在严格对比下观察了国内生产的多糖菌苗接种３０μｇ及５０μｇ一年内的血清杀菌抗体反应。结果完全相同；而全身反应则３０μｇ为５０μｇ剂量的五分之一。在我国８０年代流脑流行地区内确证了３０μｇ免后人群保护率为９９％与国外５０μｇ的保护率（９７．２％）相似。国内连续三年在流行地区内对比观察了３０μｇ、与５０μｇ的流行病学预防效果，其人群保护率相似．与国外（Ｒｅｉｎｇｏｌｄ）．的报告亦相似。最后结论是本菌苗的最适免疫剂量为３０μｇ．不但其预防效果与５０μｇ相同，而且菌苗反应轻微，经济效益高，有利于在发展中国家推广使用。     

预防接种与自身免疫病的关系

感染与自身免疫性疾病之间的联系已引出一场争论 :疫苗是否也能激发自身免疫性疾病。有关这种风险有众多正反两方面的主张。在此复习感染诱导自身免疫病的相关机制 ,并对预防接种和自身免疫病之间的相对危险度进行评估。     

Predicting the dynamic effects of rubella vaccination programmes

In the Netherlands, prepubertal girls have been vaccinated against rubella since 1974 (the UK strategy). Recently the Dutch Health Council advocated the introduction of an elimination strategy: vaccination of 1- and 9-year-old children. Dynamic effects of both strategies are studied using deterministic and stochastic models. Estimates of several epidemiological parameters are given. All computations and simulations were performed using as much field data as possible. Under the old strategy a new equilibrium is expected around the years 1995 to 2000; the new strategy is estimated to eliminate rubella (CRS) in large parts of the population 3 to 5 years after its initiation. Possible consequences of the new strategy on a cluster of people who refuse vaccination are investigated.     

Characterization of the immunological memory state generated in mice susceptible to Leishmania major following exposure to low doses of L. major and resulting in resistance to a normally pathogenic challenge

BALB/c mice are susceptible to a high-dose infection of the protozoan Leishmania major, which induces a parasite-specific antibody, Th2-like response, exclusive of a significant and protective cell-mediated Th1 component. We have shown, in contrast, that infection with a low number of parasites induces cell-mediated immunity exclusive of antibody production, and results in resistance to substantial subsequent high-dose infection. Low-dose exposure thus constitutes effective vaccination. In the present study, we analyze lymphokine production by parasite-specific T cells from these low-dose exposed, resistant mice and from normal, susceptible mice following high-dose infection. Two findings stand out. First, the parasite-specific T cells in mice rendered resistant appear not to be in an activated, effector state at the time of parasite challenge, as assessed by lack of lymphokine production on short-term stimulation with parasite antigens, but to be rather in a memory state. Second, the ratio of parasite antigen-dependent production of interferon-γ to that of interleukin-4 by spleen cells of low-dose exposed and normal mice upon high-dose challenge takes a dramatically different course. This ratio is similar in both groups of mice shortly after challenge, but increases dramatically in the resistant and declines dramatically in the control mice over a period of weeks, such that these ratios differ by about 60-fold 12 weeks after the high-dose challenge. In addition, we show that a similar state of resistance occurs following low-dose infection with a more virulent strain of L. major. In toto, our observations suggest that resistance may be generally achievable by low-dose exposure and may be associated with a memory state which, when activated by parasite challenge, results in the evolution of the response over weeks such that the protective, Th1 component becomes ever more dominant over the Th2 component.     

Antibodies against the extracellular enveloped virus B5R protein are mainly responsible for the EEV neutralizing capacity of vaccinia immune globulin

In the event of smallpox bioterrorism, widespread vaccination may be required. Vaccinia immune globulin (VIG) has been used to treat complications from the smallpox vaccine. While the potency of VIG was defined by its ability to neutralize intracellular mature virus, a second form of vaccinia called the extracellular enveloped virus (EEV) is critical for virus spread in the host. The B5R-protein is one of many EEV-specific proteins. Immunoprecipitation and ELISA revealed that VIG recognizes the B5R-protein. An EEV plaque-reduction assay using a recombinant vaccinia that lacks the majority of the extracellular domain of B5R showed that the ability of VIG to neutralize EEV is principally directed at B5R. In addition, absorbing out the anti-B5R antibody present in VIG through the addition of recombinant B5R protein abrogated VIG's ability to significantly neutralize wild-type EEV. This work demonstrates the prominent role of B5R as a target of EEV-neutralizing activity of human antibodies.     

Antibody responses to Toxoplasma gondii antigen in human peripheral blood lymphocyte-reconstituted severe-combined immunodeficient mice reproduce the immunological status of the lymphocyte donor

These studies describe the production of specific antibodies in human peripheral blood lymphocyte-reconstituted severe-combined immunodeficient (PBL-SCID) mice following vaccination with antigen from the protozoan parasite Toxoplasma gondii. To determine the effect of previous exposure of the lymphocyte donor to antigen, human-PBL-SCID animals were created by transferring peripheral blood lymphocytes from either a single T. gondii-seronegative or a single seropositive donor. These reconstituted animals were subsequently inoculated with T. gondii soluble tachyzoite antigen (STAg) entrapped within non-ionic surfactant vesicles as an immunological adjuvant. Animals were bled at pre-determined time points post-vaccination and the expression of human anti-STAg antibodies in the plasma determined by enzyme-linked immunosorbent assay. Human antibodies specific for STAg were readily inducible in both groups of reconstituted animals, although the pattern of isotype production differed markedly between groups. The response in animals reconstituted with lymphocytes from the T. gondii-seronegative donor consisted primarily of IgM and subsequently of IgG (predominantly IgG1). In animals reconstituted with lymphocytes from the seropositive donor, no parasite-specific IgM could be demonstrated. The detectable response to STAg consisted entirely of human antibodies of the IgG isotype (IgG1), indicative of a memory-type response. These results mimicked exactly the antibody responses that would be expected had the lymphocyte donors been directly challenged with either the antigen or the live infectious agent, demonstrating that the immune system within these animals is functional and reproducible with regard to both the primary and secondary responses of the human donors.     

HBV pre-vaccination screening in hospital personnel: Cost-effectiveness analysis

The purpose of this study was to identify the most cost effective method for screening subjects for hepatitis B vaccination. Such a method would ideally permit detection of all susceptible individuals at the lowest possible cost.Two-hundred-five hospital workers from the Piedmont region of Italy participated in the study. The sero-epidemiological conditions of this group with regard to hepatitis B markers was representative of hospital workers in this region as a whole. All subjects, excluding carriers, persons with anti-HBs titers 10 mIU and subjects positive for anti-HBc at a 1/100 dilution, were vaccinated. Their responses were evaluated 15 days and 1 month after vaccination. The presence of a booster effect following vaccination was correlated with the immunological status of the subject at the time of pre-vaccination screening.In the light of the results obtained, 5 screening procedures and the procedure of vaccination without screening were evaluated. The most cost effective screening strategy proved to be that of sequential testing for anti-HBc, anti-HBs and finally HBsAg and vaccination of the following subjects: those who were negative for anti-HBc, those who were anti-HBc-positive with anti-HBs titers 10相似文献