Immunogenicity of meningococcal quadrivalent (serogroup A, C, W135 and Y) tetanus toxoid conjugate vaccine: systematic review and meta-analysis

Efficacy and Safety of Quadrivalent Conjugate Meningococcal Vaccines: A Systematic Review and Meta-Analysis

Over the last decades, different quadrivalent antimeningococcal vaccine formulations (diphteria toxoid conjugate, MenACWY-D; tetanus toxoid conjugate, MenACWY-TT; CRM₁₉₇ protein conjugate, MenACWY-CRM) have been developed. However, their availability varies, both in terms of authorized formulations and of inclusion in vaccination schedules. Furthermore, several countries include only the monovalent meningococcal C (MenC) vaccine in their immunization programmes. Finally, there is currently no updated systematic review that directly compares the MenACWY formulations. Thus, we summarized the evidence on efficacy and safety through four parallel, independent systematic literature reviews with meta-analysis which included randomized controlled trials comparing the abovementioned vaccines. A total of 16 studies have been included. In terms of efficacy, MenACWY-TT outperformed MenACWY-D and MenACWY-CRM for A, W-135, and Y serogroups, while no significant difference was found for serogroup C. Furthermore, we did not find significant differences in efficacy between MenC and MenACWY-TT. Regarding the safety, we were able to perform a quantitative analysis only between MenACWY-TT and MenC, finding no significant differences. Similarly, among the different MenACWY formulations no relevant differences were identified. These findings suggest that MenACWY-TT could be preferable to other formulations to improve current vaccination programs and to better develop future immunization policies.

Carbohydrate based meningococcal vaccines: past and present overview

Neisseria meningitidis is a major cause of bacterial meningitidis worldwide. Children less than five years and adolescents are particularly affected. Nearly all invasive strains are surrounded by a polysaccharide capsule, based on which, 12 N. meningitidis serogroups are differentiated. Six of them, A, B, C, W, X, and Y, cause the vast majority of infections in humans. Mono- and multi-valent carbohydrate-based vaccines against meningococcal infections have been licensed or are currently in clinical development. In this mini-review, an overview of the past and present approaches for producing meningococcal glycoconjugate vaccines is provided.

A systematic literature review on the prevalence and etiology of meningitis among critically ill and hospitalized patients in India

BACKGROUND

In India, owing to multiple factors, such as insufficient laboratory capacity, poor reporting systems due to limited access to healthcare facilities and limited disease surveillance programmes, the actual disease burden of meningitis is unknown and may be largely under-reported.

OBJECTIVE

A systematic literature review was performed to describe: (a) the prevalence of meningitis; and (b) its etiological pathogen across different regions, age groups and patients with comorbidities.

METHOD

A systematic literature search was conducted between 1990 and 2020 using PubMed and Google Scholar databases to identify Indian studies reporting the prevalence rates and etiology of meningitis. A total of 51 studies were included in the final analysis.

RESULTS

A total of 38 studies reported prevalence of meningitis and 21 studies reported data on the etiology of meningitis in India. These studies included mixed patient populations: (a) pyogenic meningitis; (b) meningitis in sick or hospitalized patients with tuberculosis, acute febrile encephalopathy syndrome, septicaemia, invasive pneumococcal disease or respiratory compromise; and (c) meningitis patients with comorbidities. The prevalence of confirmed bacterial meningitis in the pediatric population (0-14 years) ranged between 0.5% and 61.8%. A total of seven studies reported the prevalence of meningitis in patients of all age groups (0-75 years), with prevalence ranging between 8.68% and 78.85%. Cryptococcal meningitis was predominant in patients with positive HIV/AIDS, with a prevalence ranging between 2.09% and 53.1%. Streptococcus pneumoniae was found to be the predominant pathogen causing meningitis across different regions of India, with a frequency ranging from 4% to 61.8% in patients of all age groups.

CONCLUSION

This systematic literature review displayed the possible range of frequency of bacterial meningitis pathogens across a wide variety of age groups in different regions of India. Further studies are warranted to monitor meningitis cases, which may facilitate the development of prevention and treatment strategies in India.

Meningococcal Vaccines: Current Status and Emerging Strategies

Neisseria meningitidis causes most cases of bacterial meningitis. Meningococcal meningitis is a public health burden to both developed and developing countries throughout the world. There are a number of vaccines (polysaccharide-based, glycoconjugate, protein-based and combined conjugate vaccines) that are approved to target five of the six disease-causing serogroups of the pathogen. Immunization strategies have been effective at helping to decrease the global incidence of meningococcal meningitis. Researchers continue to enhance these efforts through discovery of new antigen targets that may lead to a broadly protective vaccine and development of new methods of homogenous vaccine production. This review describes current meningococcal vaccines and discusses some recent research discoveries that may transform vaccine development against N. meningitidis in the future.

N. meningitidis and TLR Polymorphisms: A Fascinating Immunomodulatory Network

N. meningitidis infections represent a global health problem that can lead to the development of serious permanent sequelae. Although the use of antibiotics and prevention via vaccination have reduced the incidence of meningococcal disease, our understanding regarding N. meningitidis pathogenesis is still limited, especially of those mechanisms responsible for IMD and fulminant or deadly septic shock. These severe clinical presentations occur in a limited number of subjects, whereas about 10% of healthy individuals are estimated to carry the bacteria as a commensal. Since TLR activation is involved in the defense against N. meningitidis, several studies have highlighted the association between host TLR SNPs and a higher susceptibility and severity of N. meningitidis infections. Moreover, TLR SNPs induced variations in immunological responses and in their persistence upon vaccination against meningococcal disease. In the absence of mass vaccination programs, the early identification of risk factors for meningococcal disease would be recommended in order to start immunization strategies and antibiotic treatment in those subjects carrying the risk variants. In addition, it could allow us to identify individuals with a higher risk for severe disease and sequelae in order to develop a personalized healthcare of high-risk subjects based on their genomic profile. In this review, we have illustrated important preliminary correlations between TLR variants and meningococcal susceptibility/severity and with vaccine-induced immune responses.

Risk of gastrointestinal complications associated to NSAIDs, low-dose aspirin and their combinations: Results of a pharmacovigilance reporting system

Gastrointestinal (GI) complications are one of the most limiting cause of use of NSAIDs. Beyond others well defined factors, history of peptic ulcer, older age, Helicobacter pylori infection and use of gastrotoxic drugs may affect their GI safety profile. In particular, the risk of GI complications associated to the use of antiplatelet drugs, especially low-dose acetylsalicylic acid (LDA) should deserve much attention. However, only few studies have focused on the effect of combination LDA/NSAIDs on the GI tract compared with the monotherapy and much less studies assessed this effect with multiple NSAIDs use. We aimed to characterize the GI safety profile of NSAIDs and LDA as monotherapy or their combinations in real-life conditions by analysing spontaneous adverse drug reactions (ADRs) reporting system in a Southern Italy. We used the case/non-case method in the Italian Pharmacovigilance Network (RNF). Cases were reports of GI events in the RNF between January 2007 and December 2011. Non-cases were all other reports during the same period. The association between NSAID and suspected GI ADRs was calculated using the reporting odds ratio (ROR) with 95% confidence intervals as a measure of disproportionality while adjusting for age, and concomitant use of antineoplastic agents or drugs for cardiovascular diseases. Sub-analysis were performed within the NSAID class. Among the 2816 adverse drug reactions recorded, we identified 374 (13.3%) cases of GI complications. Upper GI complications were the most frequently reported type of events. The highest associations were found for the combined use of NSAIDs and/or LDA, whilst the lowest associations were for their respective monotherapy. Looking at individual NSAIDs the highest association with GI events was observed for ketorolac exposure followed by nimesulide, diclofenac, aspirin, ketoprofen, and ibuprofen. This study highlights the primary role of the national spontaneous reporting system to bring out potential signals, such as the inappropriate drug use pattern, which however, have to be furtherly studied in-depth with ad hoc population-based studies.

The role of Toll-like receptor 4 polymorphisms in vaccine immune response

Toll-like receptors (TLRs) are a class of pattern recognition receptors that are deputed to recognise a range of molecular structures in pathogens. One of the most studied members of this family is the TLR4, which is essential for the signalling of lipopolysaccharide. The gene encoding for TLR4 is highly polymorphic and this genetic variability may explain in part the interindividual variability observed in several clinical setting, including the response to vaccination. Herein, we review and systematise the available scientific evidence about the effect of TLR4 polymorphisms on vaccine response, including approved prophylactic, new therapeutic cancer vaccines and recently approved vaccine adjuvants. Data reviewed in this analysis indicate that TLR4 polymorphisms significantly affect vaccine response. If these results are confirmed by further analyses, the use of these genetic biomarkers may become a useful tool to tailor vaccination in specific subsets of patients.