Stroke Risk After COVID-19 Bivalent Vaccination Among US Older Adults.

Importance: In January 2023, the US Centers for Disease Control and Prevention and the US Food and Drug Administration noted a safety concern for ischemic stroke among adults aged 65 years or older who received the Pfizer-BioNTech BNT162b2; WT/OMI BA.4/BA.5 COVID-19 bivalent vaccine. Objective: To evaluate stroke risk after administration of (1) either brand of the COVID-19 bivalent vaccine, (2) either brand of the COVID-19 bivalent plus a high-dose or adjuvanted influenza vaccine on the same day (concomitant administration), and (3) a high-dose or adjuvanted influenza vaccine. Design, Setting, and Participants: Self-controlled case series including 11 001 Medicare beneficiaries aged 65 years or older who experienced stroke after receiving either brand of the COVID-19 bivalent vaccine (among 5 397 278 vaccinated individuals). The study period was August 31, 2022, through February 4, 2023. Exposures: Receipt of (1) either brand of the COVID-19 bivalent vaccine (primary) or (2) a high-dose or adjuvanted influenza vaccine (secondary). Main Outcomes and Measures: Stroke risk (nonhemorrhagic stroke, transient ischemic attack, combined outcome of nonhemorrhagic stroke or transient ischemic attack, or hemorrhagic stroke) during the 1- to 21-day or 22- to 42-day risk window after vaccination vs the 43- to 90-day control window. Results: There were 5 397 278 Medicare beneficiaries who received either brand of the COVID-19 bivalent vaccine (median age, 74 years [IQR, 70-80 years]; 56% were women). Among the 11 001 beneficiaries who experienced stroke after receiving either brand of the COVID-19 bivalent vaccine, there were no statistically significant associations between either brand of the COVID-19 bivalent vaccine and the outcomes of nonhemorrhagic stroke, transient ischemic attack, nonhemorrhagic stroke or transient ischemic attack, or hemorrhagic stroke during the 1- to 21-day or 22- to 42-day risk window vs the 43- to 90-day control window (incidence rate ratio [IRR] range, 0.72-1.12). Among the 4596 beneficiaries who experienced stroke after concomitant administration of either brand of the COVID-19 bivalent vaccine plus a high-dose or adjuvanted influenza vaccine, there was a statistically significant association between vaccination and nonhemorrhagic stroke during the 22- to 42-day risk window for the Pfizer-BioNTech BNT162b2; WT/OMI BA.4/BA.5 COVID-19 bivalent vaccine (IRR, 1.20 [95% CI, 1.01-1.42]; risk difference/100 000 doses, 3.13 [95% CI, 0.05-6.22]) and a statistically significant association between vaccination and transient ischemic attack during the 1- to 21-day risk window for the Moderna mRNA-1273.222 COVID-19 bivalent vaccine (IRR, 1.35 [95% CI, 1.06-1.74]; risk difference/100 000 doses, 3.33 [95% CI, 0.46-6.20]). Among the 21 345 beneficiaries who experienced stroke after administration of a high-dose or adjuvanted influenza vaccine, there was a statistically significant association between vaccination and nonhemorrhagic stroke during the 22- to 42-day risk window (IRR, 1.09 [95% CI, 1.02-1.17]; risk difference/100 000 doses, 1.65 [95% CI, 0.43-2.87]). Conclusions and Relevance: Among Medicare beneficiaries aged 65 years or older who experienced stroke after receiving either brand of the COVID-19 bivalent vaccine, there was no evidence of a significantly elevated risk for stroke during the days immediately after vaccination.

First-in-human assessment of safety and immunogenicity of low and high doses of Plasmodium falciparum malaria protein 013 (FMP013) administered intramuscularly with ALFQ adjuvant in healthy malaria-naïve adults.

The global burden of malaria remains substantial. Circumsporozoite protein (CSP) has been demonstrated to be an effective target antigen, however, improvements that offer more efficacious and more durable protection are still needed. In support of research and development of next-generation malaria vaccines, Walter Reed Army Institute of Research (WRAIR) has developed a CSP-based antigen (FMP013) and a novel adjuvant ALFQ (Army Liposome Formulation containing QS-21). We present a single center, open-label, dose-escalation Phase 1 clinical trial to evaluate the safety and immunogenicity of the FMP013/ALFQ malaria vaccine candidate. In this first-in-human evaluation of both the antigen and adjuvant, we enrolled ten subjects; five received 20 µg FMP013 / 0.5 mL ALFQ (Low dose group), and five received 40 µg FMP013 / 1.0 mL ALFQ (High dose group) on study days 1, 29, and 57. Adverse events and immune responses were assessed during the study period. The clinical safety profile was acceptable and there were no serious adverse events. Both groups exhibited robust humoral and cellular immunological responses, and compared favorably with historical responses reported for RTS,S/AS01. Based on a lower reactogenicity profile, the 20 µg FMP013 / 0.5 mL ALFQ (Low dose) was selected for follow-on efficacy testing by controlled human malaria infection (CHMI) with a separate cohort. Trial Registration:Clinicaltrials.gov Identifier NCT04268420 (Registered February 13, 2020).

[Aluminium adjuvant exposure through vaccines in France in 2018]. / Exposition à l'aluminium vaccinal en France en 2018.

OBJECTIVES: Aluminum-containing vaccine adjuvants stimulate an adequate immune response to vaccination. The safety and rapid elimination of these molecules, a guarantee of their safe use for several decades, have been challenged by a growing number of studies over the last 20 years. Evaluation of exposure to aluminum adjuvants of an individual is thus essential. The current review answers the following questions: what is the exposure of aluminum adjuvants of an individual vaccinated in France? What are the factors of variation? METHODS: To evaluate the immunization exposure to aluminum for a vaccinee in France, we used the 2018 vaccination schedule and the Social Security database for vaccines reimbursed that year. French mandatory and recommended vaccines for an individual who does not travel abroad and has no particular professional obligations have been taken into account. RESULTS: Our results show that an individual following the vaccination requirements and recommendations of 2018 receives between 2545 and 7735µg of Al3+ during his lifetime, and at least 50% before the age of 1year. Exposure varies with age, weight, sex, and choice of administered vaccines. CONCLUSION: Vaccines with higher doses of aluminum are mainly injected at the beginning of life. Women receive a proportionately larger dose than men. The most reimbursed vaccines are often those with the highest amount of aluminum salts.

Adjuvanted influenza vaccine for the Italian elderly in the 2018/19 season: an updated health technology assessment.

BACKGROUND: The elderly, defined here as subjects aged ≥ 65 years, are among at-risk subjects for whom annual influenza vaccination is recommended. For the 2018/19 season, three vaccine types are available for the elderly in Italy: trivalent inactivated vaccine (TIV), adjuvanted TIV (aTIV) and quadrivalent inactivated vaccines (QIV). No health technology assessment (HTA) of seasonal influenza vaccination in the elderly has previously been conducted in Italy. METHODS: An HTA was conducted in 2017 to analyze the burden of influenza illness, the characteristics, efficacy, safety and cost-effectiveness of available vaccines and the related organizational and ethical implications. This was then contextualized to the 2018/19 influenza season. Comprehensive literature reviews/analyses were performed and a static mathematical model developed in order to address the above issues. RESULTS: In Italy, influenza is usually less common in the elderly than in other age-classes, but the burden of disease is the highest; >10% of infected elderly subjects develop complications, and about 90% of all influenza-related deaths occur in this age-class. All available vaccines are effective, safe and acceptable from an ethical standpoint. However, aTIV has proved more immunogenic and effective in the elderly. Furthermore, from the third payer's perspective, aTIV is highly cost-effective and cost-saving in comparison with TIV and QIV, respectively. Nevertheless, vaccination coverage needs to be improved. CONCLUSIONS: According to this HTA, aTIV appeared the vaccine of choice in the elderly. HTA should be reapplied whenever new relevant data become available.

Establishment of a novel safety assessment method for vaccine adjuvant development.

Vaccines effectively prevent infectious diseases. Many types of vaccines against various pathogens that threaten humans are currently in widespread use. Recently, adjuvant adaptation has been attempted to activate innate immunity to enhance the effectiveness of vaccines. The effectiveness of adjuvants for vaccinations has been demonstrated in many animal models and clinical trials. Although a highly potent adjuvant tends to have high effectiveness, it also has the potential to increase the risk of side effects such as pain, edema, and fever. Indeed, highly effective adjuvants, such as poly(I:C), have not been clinically applied due to their high risks of toxicity in humans. Therefore, the task in the field of adjuvant development is to clinically apply highly effective and non- or low-toxic adjuvant-containing vaccines. To resolve this issue, it is essential to ensure a low risk of side effects and the high efficacy of an adjuvant in the early developmental phases. This review summarizes the theory and history of the current safety assessment methods for adjuvants, using the inactivated influenza vaccine as a model. Our novel method was developed as a system to judge the safety of a candidate compound using biomarkers identified by genomic technology and statistical tools. A systematic safety assessment tool for adjuvants would be of great use for predicting toxicity during novel adjuvant development, screening, and quality control.

Outcomes of Stable Multiple Sclerosis Patients Staying on Initial Interferon Beta Therapy Versus Switching to Another Interferon Beta Therapy: A US Claims Database Study.

INTRODUCTION: This study was designed to assess real-world outcomes of patients with multiple sclerosis (MS) who were stable on interferon (IFN) beta therapy in the year prior to switching to another IFN beta therapy versus those who continued on the initial treatment. METHODS: This study used administrative claims from MarketScan Commercial Claims and Encounters Database, from January 1, 2010, to March 31, 2015, to identify MS patients aged 18-64 years who remained relapse free for at least 1 year while continuously treated with an IFN beta therapy. Stable patients remaining on their initial IFN beta therapy (no-switch patients) were matched with stable patients who switched IFN beta therapy (switch patients) using propensity score matching (first claim = index date). Outcome measures included annualized relapse rate (ARR), the percentage of patients who relapsed, medication possession ratio, and the proportion of days covered and were measured during the year following the index date. RESULTS: This study identified 531 patients in the no-switch group and 177 patients in the switch group, with subsets of 270 patients in the no-switch group and 90 patients in the switch group stable on intramuscular (IM) IFN beta-1a therapy. All outcomes during the follow-up year were significantly better in the no-switch group than in the switch group. For all patients, ARR in the switch group was more than twice that in the no-switch group (P = 0.002). For patients stable on IM IFN beta-1a at baseline, ARR was twice as high in the switch group as in the no-switch group (P = 0.012). CONCLUSION: Among all patients stable on IFN beta therapy and the subset stable on IM IFN beta therapy in particular, those who remained on therapy had significantly better outcomes than those who switched to another IFN beta therapy. FUNDING: Biogen (Cambridge, MA, USA).

Incidence rates of narcolepsy diagnoses in Taiwan, Canada, and Europe: The use of statistical simulation to evaluate methods for the rapid assessment of potential safety issues on a population level in the SOMNIA study.

BACKGROUND & OBJECTIVES: Vaccine safety signals require investigation, which may be done rapidly at the population level using ecological studies, before embarking on hypothesis-testing studies. Incidence rates were used to assess a signal of narcolepsy following AS03-adjuvanted monovalent pandemic H1N1 (pH1N1) influenza vaccination among children and adolescents in Sweden and Finland in 2010. We explored the utility of ecological data to assess incidence of narcolepsy following exposure to pandemic H1N1 virus or vaccination in 10 sites that used different vaccines, adjuvants, and had varying vaccine coverage. METHODS: We calculated incidence rates of diagnosed narcolepsy for periods defined by influenza virus circulation and vaccination campaign dates, and used Poisson regression to estimate incidence rate ratios (IRRs) comparing the periods during which wild-type virus circulated and after the start of vaccination campaigns vs. the period prior to pH1N1 virus circulation. We used electronic health care data from Sweden, Denmark, the United Kingdom, Canada (3 provinces), Taiwan, Netherlands, and Spain (2 regions) from 2003 to 2013. We investigated interactions between age group and adjuvant in European sites and conducted a simulation study to investigate how vaccine coverage, age, and the interval from onset to diagnosis may impact the ability to detect safety signals. RESULTS: Incidence rates of narcolepsy varied by age, continent, and period. Only in Taiwan and Sweden were significant time-period-by-age-group interactions observed. Associations were found for children in Taiwan (following pH1N1 virus circulation) and Sweden (following vaccination). Simulations showed that the individual-level relative risk of narcolepsy was underestimated using ecological methods comparing post- vs. pre-vaccination periods; this effect was attenuated with higher vaccine coverage and a shorter interval from disease onset to diagnosis. CONCLUSIONS: Ecological methods can be useful for vaccine safety assessment but the results are influenced by diagnostic delay and vaccine coverage. Because ecological methods assess risk at the population level, these methods should be treated as signal-generating methods and drawing conclusions regarding individual-level risk should be avoided.

Health-related quality of life after BCG or MMC induction for non-muscle invasive bladder cancer.

INTRODUCTION: To evaluate health-related quality of life (HRQoL) in patients with non-muscle invasive bladder cancer (NMIBC) during the induction phase of intravesical instillations with BCG or MMC. MATERIALS AND METHODS: HRQoL was measured by two questionnaires from EORTC (QLQ-C30 and QLQ-BLS24), stratifying results by gender, age and therapy at the start of the therapy (T0), at last instillation (T1) and at 3 months after T1 (T2). The persistence of QoL-related side effects after 3 months from the end of the induction cycle was evaluated. RESULTS: We enrolled 108 naïve patients and 103 patients self-completed the questionnaires. Treatment was well tolerated in both groups. Side effects were reported by 46.6% of patients at T1 and 47.5% of patients at T2. QoL dropped at T1, returning to the baseline at T2. Drop of QoL was greater in the physical, role, emotional and social functioning domains and in some clinical domains as pain, fatigue and insomnia. Our stratified analysis showed that patients > 70 years have a worsening of QoL, a higher incidence of patient-reported side effects or symptoms in the BCG arm as compared to MMC arm. CONCLUSIONS: Our study shows that intravesical instillations of BCG or MMC during the induction phase might have a relevant effect on HRQoL.

Leaf saponins of Quillaja brasiliensis enhance long-term specific immune responses and promote dose-sparing effect in BVDV experimental vaccines.

Saponin-based adjuvants are promising adjuvants that enhance both humoral and T-cell-mediated immunity. One of the most used natural products as vaccine adjuvants are Quillaja saponaria bark saponins and its fraction named Quil A®. Despite that, its use has been restricted for human use due to safety issues. As an alternative, our group has been studying the congener species Quillaja brasiliensis saponins and its performance as vaccine adjuvants, which have shown to trigger humoral and cellular immune responses comparable to Quil A® but with milder side effects. Here, we studied a semi purified aqueous extract (AE) and a previously little characterized saponin-enriched fraction (QB-80) from Q. brasiliensis as vaccine adjuvants and an inactivated virus (bovine viral diarrhea virus, BVDV) antigen co-formulated in experimental vaccines in mice model. For the first time, we show the spectra pattern of the Q. brasiliensis saponins by MALDI-TOF, a novel and cost-effective method that could be used to characterize different batches during saponins production. Both AE and QB-80 exhibited noteworthy chemical similarities to Quil A®. In addition, the haemolytic activity and toxicity were assessed, showing that both AE and QB-80 were less toxic than Quil A®. When subcutaneously inoculated in mice, both fractions promoted long-term strong antibody responses encompassing specific IgG1 and IgG2a, enhanced the avidity of IgG antibodies, induced a robust DTH reaction and significantly increased IFN-É£ production in T CD4+ and T CD8+ cells. Furthermore, we have proven herein that AE has the potential to promote dose-sparing, substantially reducing the dose of antigen required for the BVDV vaccines and still eliciting a mixed Th1/Th2 strong immune response. Based on these results, and considering that AE is a raw extract, easier and cheaper to produce than commercially available saponins, this product can be considered as candidate to be escalated from experimental to industrial uses.

Adjuvants for allergy immunotherapeutics.

Allergic diseases are reaching epidemic proportions in developed countries. In particular, food allergy is increasing in prevalence and severity, thus becoming an important socioeconomic burden. Numerous cell types and cell populations, which form an intricate and balanced network, are involved in an immune response. This balance is occasionally disturbed, leading to the onset of different diseases, such as allergic diseases. Antihistamines and corticosteroids provide some degree of relief from the symptoms of allergic conditions. However, the only treatment that can revert the disease is immunotherapy. Nevertheless, specific immunotherapy has at least 2 major drawbacks: it is time-consuming, and it can produce local and even systemic allergic side effects. Immunotherapy's potential goes beyond our current knowledge of the immune response; nevertheless, we can still design strategies to reach a safer immune modulation for treating allergies. This review deals with the use of adjuvants to reduce the undesirable side effects associated with specific allergen immunotherapy. For example, nanoparticles used as immunoadjuvants are offering promising results in preclinical assays.

Cost-effectiveness analysis of ocrelizumab versus subcutaneous interferon beta-1a for the treatment of relapsing multiple sclerosis.

AIM: To conduct a cost-effectiveness analysis to compare ocrelizumab vs subcutaneous (SC) interferon beta-1a for the treatment of relapsing multiple sclerosis (RMS). METHODS: A Markov cohort model with a 20-year horizon was developed to compare ocrelizumab with SC interferon beta-1a from a US payer perspective. A cohort of patients with relapsing-remitting MS (RRMS) and Expanded Disability Status Scale (EDSS) scores of 0-6, who initiated treatment with ocrelizumab or SC interferon beta-1a, were entered into the model. The model considered 21 health states: EDSS 0-9 in RRMS, EDSS 0-9 in secondary-progressive multiple sclerosis (SPMS), and death. Patients with RRMS could transition across EDSS scores, progress to SPMS, experience relapses, or die. Transition probabilities within RRMS while patients received ocrelizumab or SC interferon beta-1a were based on data from the two SC interferon beta-1a-controlled Phase III OPERA I and OPERA II trials of ocrelizumab in RMS. Transitions within RRMS when off-treatment, RRMS-to-SPMS transitions, transitions within SPMS, and transitions to death were based on the literature. Utilities of health states, disutilities of relapses, costs of therapies, and medical costs associated with health states, relapse, and adverse events were from the literature and publicly available data sources. The model estimated per-patient total costs, incremental cost per life year (LY) gained, and incremental cost per quality-adjusted LY (QALY) gained. Deterministic sensitivity analyses (DSA) and probabilistic sensitivity analysis (PSA) were conducted to evaluate the robustness of the model results. RESULTS: Ocrelizumab was associated with a cost savings of $63,822 and longer LYs (Δ = 0.046) and QALYs (Δ = 0.556) over a 20-year time horizon. The results of the model were robust in the DSA and PSA. LIMITATIONS: The model did not consider subsequent treatments and their impact on disease progression. CONCLUSIONS: The results suggest that ocrelizumab is more cost-effective than SC interferon beta-1a for the treatment of RMS.

[Seasonal flu vaccination for older people: Evaluation of the adjuvanted vaccine. Positioning report]. / Vacunación frente a la gripe estacional en las personas mayores. Evaluación de la vacuna adyuvada: Informe de posicionamiento.

Flu is a major public health problem, particularly for older people, and creates an important clinical and economic burden. A high mortality rate was reported in Spain during the period 2015 to 2016; 3,101 serious cases were hospitalised with a confirmed diagnosis of flu, of which 11% died (352 cases). Furthermore, financial and health costs are greatly increased by the complications of flu; people aged over 65 years represent approximately 64% of the total costs. Seasonal flu vaccination is the fundamental strategy, as demonstrated by cost-benefit and cost-effectiveness studies. A priority objective is to improve the vaccine's immune response and the search for and inclusion of adjuvants and immunostimulants in vaccines is a major line of research. This positioning report evaluates vaccination for older people and the importance of the adjuvanted vaccine in the elderly in strengthening immunogenicity, by means of a critical review of the literature based on the best evidence available on its immunogenicity and effectiveness, and an economic assessment.

Assessment of Prime-boost Vaccination Using an AS03B-adjuvanted Influenza A (H5N1) Vaccine: A Randomized Trial in Children of Three to Less Than Eighteen Years of Age.

BACKGROUND: Heterologous prime-boost vaccination is a pandemic response strategy utilizing subtype-matched vaccine at pandemic onset followed by strain-matched vaccine once available. Persistence of immune response and safety of influenza A (H5N1) vaccine adjuvanted with adjuvant system containing α-tocopherol and squalene in an oil-in-water emulsion (AS03B) were evaluated. METHODS: An open phase 3 active-controlled study (www.clinicaltrials.gov NCT01379937) assessed immunogenicity and reactogenicity of a heterologous booster dose of A/turkey/Turkey/1/2005-H5N1-AS03B in children 3 to <18 years of age, given 6 months after 2-dose priming with A/Indonesia/05/2005-H5N1-AS03B (H5N1(2) -H5N1 group) compared with a single dose of A/turkey/Turkey/1/2005-H5N1-AS03B in unprimed subjects (hepatitis A vaccine (HAV)-H5N1 group). Hemagglutinin inhibition responses and microneutralization antibodies were assessed to 6 months after booster vaccination. RESULTS: Hemagglutinin inhibition antibody responses against A/turkey/Turkey/1/2005-H5N1 were superior in the H5N1(2)-H5N1 versus the hepatitis A vaccine-H5N1 group overall and in each age strata (3 to <10 and 10 to <18 years). Anamnestic immune responses were demonstrated against vaccine-homologous/heterologous strains in the H5N1(2)-H5N1 group. Injection site pain and fever increased with consecutive doses for children <6 years (H5N1(2)-H5N1). Immune responses to vaccine-homologous/heterologous strains persisted to 6 months after booster vaccination in the H5N1(2)-H5N1 group. CONCLUSIONS: Heterologous H5N1-AS03B-adjuvanted booster vaccination in children/adolescents was immunogenic for vaccine-homologous and heterologous strains following 2-dose priming, with immune persistence for at least 6 months. Prime-boost strategies using H5N1-AS03 could be effectively employed in this age group.

Fluorescent nanodiamonds as a relevant tag for the assessment of alum adjuvant particle biodisposition.

BACKGROUND: Aluminum oxyhydroxide (alum) is a crystalline compound widely used as an immunologic adjuvant of vaccines. Concerns linked to alum particles have emerged following recognition of their causative role in the so-called macrophagic myofasciitis (MMF) lesion in patients with myalgic encephalomyelitis, revealing an unexpectedly long-lasting biopersistence of alum within immune cells and a fundamental misconception of its biodisposition. Evidence that aluminum-coated particles phagocytozed in the injected muscle and its draining lymph nodes can disseminate within phagocytes throughout the body and slowly accumulate in the brain further suggested that alum safety should be evaluated in the long term. However, lack of specific staining makes difficult the assessment of low quantities of bona fide alum adjuvant particles in tissues. METHODS: We explored the feasibility of using fluorescent functionalized nanodiamonds (mfNDs) as a permanent label of alum (Alhydrogel(®)). mfNDs have a specific and perfectly photostable fluorescence based on the presence within the diamond lattice of nitrogen-vacancy centers (NV centers). As the NV center does not bleach, it allows the microspectrometric detection of mfNDs at very low levels and in the long-term. We thus developed fluorescent nanodiamonds functionalized by hyperbranched polyglycerol (mfNDs) allowing good coupling and stability of alum:mfNDs (AluDia) complexes. Specificities of AluDia complexes were comparable to the whole reference vaccine (anti-hepatitis B vaccine) in terms of particle size and zeta potential. RESULTS: In vivo, AluDia injection was followed by prompt phagocytosis and AluDia particles remained easily detectable by the specific signal of the fND particles in the injected muscle, draining lymph nodes, spleen, liver and brain. In vitro, mfNDs had low toxicity on THP-1 cells and AluDia showed cell toxicity similar to alum alone. Expectedly, AluDia elicited autophagy, and allowed highly specific detection of small amounts of alum in autophagosomes. CONCLUSIONS: The fluorescent nanodiamond technology is able to overcome the limitations of previously used organic fluorophores, thus appearing as a choice methodology for studying distribution, persistence and long-term neurotoxicity of alum adjuvants and beyond of other types of nanoparticles.

A review on the association between inflammatory myopathies and vaccination.

Several viruses and vaccines are among the environmental factors implicated as triggers of autoimmune inflammatory myopathies. Case histories report on the onset of dermatomyositis/polymyositis after immunization with various vaccines of patients with probable genetic predisposition. However, retrospective and epidemiological studies failed to ascertain an association between DM/PM and vaccines: no significant increase in the incidence of DM/PM was reported after large vaccination campaigns. The risk for vaccine-induced adverse events may be enhanced by adjuvants. Macrophagic myofasciitis is a novel inflammatory myopathy ascribed to an ongoing local immune reaction to a vaccine adjuvant. Isolated prospective studies showed that the administration of unadjuvanted, non-live vaccine to patients with DM/PM caused no short-term harmful effects to DM/PM immune processes. However, more research is warranted to clarify the incidence of vaccine-preventable infections, harmful effects of vaccination, and the influence of any immunomodulating agents on vaccination efficacy. Vaccination is an important disease prevention tool in modern medicine. This review does not address risk-benefit or cost-benefit analyses, and does not advocate the use of specific vaccines or vaccination programs. Despite a great deal of scientific uncertainty, the concept of a possible causal link between immunization and inflammatory myopathies should not be totally rejected.

Genotoxicity assessment of vaccine adjuvant squalene.

The genotoxic potential of the vaccine adjuvant Squalene was assessed by the chromosomal aberrations (CAs), sister chromatid exchanges (SCEs) and micronucleus (MNs) tests in human lymphocytes and comet assay in both human and rat lymphocytes. Five different concentrations of squalene (1250-20,000 µg/ml for human lymphocytes and 0.07-1.12 mg/kg for rat lymphocytes) were studied. Squalene did not affect the CAs and MN frequency, in all treatments in vitro. A significant increase in SCEs was observed in almost all concentrations at 24 h treatment. Squalene did not affect significantly the comet tail length (CTL) (except 2500 µg/ml) and comet tail intensity (CTI) at all treatments in vitro. In rats, squalene significantly increased and decreased CTL and CTI in some doses. Although there are increasing and reduction in the effect, squalene cannot be regarded as genotoxic in human lymphocytes. However, further in vivo studies are required to be sure on the effect.

An assessment of prime-boost vaccination schedules with AS03A -adjuvanted prepandemic H5N1 vaccines: a randomized study in European adults.

BACKGROUND: Long-term persistence of immune response and safety of an H5N1 prepandemic influenza vaccine adjuvanted with AS03 (an α-tocopherol oil-in-water emulsion-based adjuvant system) was evaluated using various prime-boost schedules that mimicked potential pandemic scenarios (NCT00430521). METHODS: Five hundred and twelve healthy adults aged 18-60 years received primary vaccination with one or two doses (0, 21 days schedule) of the A/Vietnam/1194/2004 H5N1 vaccine followed by a booster dose (A/Vietnam/1194/2004 or A/Indonesia/05/2005 strain) six or twelve months later across eight randomized groups. Immunogenicity results by hemagglutination inhibition [HI] assay, microneutralization assay, and the cell-mediated immune response (CMI) are reported here for the four groups boosted at Month 12. RESULTS: A one-dose-adjuvanted primary administration followed 12 months later by a single-adjuvanted booster dose containing a heterologous vaccine strain met or exceeded all US and European criteria for both strains. Increasing the interval between the first and second dose (from 21 days to 12 months) resulted in stronger cross-reactive immune responses against the A/Indonesia/05/2005 strain. The HI antibody response against the two strains persisted for 6 months after the booster dose irrespective of the booster vaccine's strain. The neutralizing antibody responses and the CMI observed in the study population paralleled the HI immune response. Overall, the vaccine had a clinically acceptable safety profile. CONCLUSION: The H5N1 vaccine in this study allowed for flexibility in the time interval between primary and booster vaccination and the use of a heterologous strain without impacting the strength of the humoral and cellular immune response to both vaccine strains.