Clinical efficacy and safety of high dose trivalent influenza vaccine in adults and immunosuppressed populations - A systematic review and meta-analysis

Systematic review of influenza vaccine effectiveness against laboratory-confirmed influenza among older adults living in aged care facilities

We estimated the effectiveness of influenza vaccines in preventing laboratory-confirmed influenza among older adults in aged care. Electronic database searches were conducted using search terms, and studies were selected as per the selection criteria. Fourteen studies were included for final review. The studies exhibited considerable variation in reported vaccine effectiveness (VE) across different seasons. Among the observational studies, VE ranged from 7.2% to 89.8% against laboratory-confirmed influenza across different vaccines. Randomized clinical trials demonstrated a 17% reduction in infection rates with the adjuvanted trivalent vaccine. The limitations include the small number of included studies conducted in different countries or regions, varied seasons, variations in diagnostic testing methods, a focus on the A/H3N2 strain, and few studies available on the effectiveness of enhanced influenza vaccines in aged care settings. Despite challenges associated with achieving optimal protection, the studies showed the benefits of influenza vaccination in the elderly residents.

Cost-effectiveness for high dose quadrivalent versus the adjuvanted quadrivalent influenza vaccine in the Italian older adult population

Objectives

To assess the cost-effectiveness of switching from adjuvanted quadrivalent vaccine (aQIV) to high-dose quadrivalent influenza vaccine (HD-QIV) in those aged ≥65 years from the Italian National Health Service perspective.

Methods

We developed a decision tree model over a 1-year time-horizon to assess influenza-related costs and health outcomes. Two hospitalization approaches were considered: "hospitalization conditional on developing influenza" and "hospitalization possibly related to Influenza." The first approach considered only hospitalizations with influenza ICD-9-CM diagnosis codes. The second included hospitalizations for cardiorespiratory events possibly related to influenza to better capture the "hidden burden". Since comparative efficacy of high-dose quadrivalent influenza vaccine versus adjuvanted quadrivalent vaccine was lacking, we assumed relative efficacy versus a common comparator, standard-dose influenza quadrivalent vaccines (SD-QIV). We assumed the relative efficacy of HD-QIV vs. SD-QIV was 24.2 and 18.2% for the first and second hospitalization approaches, respectively, based on published information. Due to lack of comparative efficacy data for aQIV vs. SD-QIV, we assumed three different scenarios: 0, 6, and 12% relative efficacy in scenarios 1, 2, and 3, respectively.

Results

For the first hospitalization approach, HD-QIV was a cost-effective alternative to aQIV in all scenarios at a willingness-to-pay threshold of €30,000 per Quality Adjusted Life Years. The incremental cost-effectiveness ratios across the scenarios were €7,301, €9,805, and €14,733, respectively, much lower than the willingness-to-pay per Quality Adjusted Life Years threshold. For the second hospitalization approach, HD-QIV was a dominant alternative to aQIV across all scenarios. The robustness of the results was confirmed in one-way and probabilistic sensitivity analyses.

Conclusion

Switching to HD-QIV from aQIV for the older adult in Italy would improve health-related outcomes, and would be cost-effective or cost saving.

Main factors influencing long-term outcomes of liver transplantation in 2022

Liver transplant (LT) outcomes have markedly improved in the recent decades, even if long-term morbidity and mortality are still considerable. Most of late deaths are independent from graft function and different comorbidities, including complications of metabolic syndrome and de novo neoplasms, seem to play a key role in determining long-term outcomes in LT recipients. This review discusses the main factors associated with late mortality and suggests possible strategies to improve long-term management and follow-up after liver transplantation. In particular, the reduction of drug toxicity, the use of tools to identify high-risk patients, and setting up a multidisciplinary team also for long-term management of LT recipients may further improve survival after liver transplantation.

Antiviral Approaches against Influenza Virus

Preventing and controlling influenza virus infection remains a global public health challenge, as it causes seasonal epidemics to unexpected pandemics. These infections are responsible for high morbidity, mortality, and substantial economic impact. Vaccines are the prophylaxis mainstay in the fight against influenza. However, vaccination fails to confer complete protection due to inadequate vaccination coverages, vaccine shortages, and mismatches with circulating strains. Antivirals represent an important prophylactic and therapeutic measure to reduce influenza-associated morbidity and mortality, particularly in high-risk populations. Here, we review current FDA-approved influenza antivirals with their mechanisms of action, and different viral- and host-directed influenza antiviral approaches, including immunomodulatory interventions in clinical development. Furthermore, we also illustrate the potential utility of machine learning in developing next-generation antivirals against influenza.

Characteristics and methodological standards across systematic reviews with Meta-analysis of efficacy and/or effectiveness of influenza vaccines: an overview of reviews

BACKGROUND

While systematic reviews (SR) generally suggest that vaccination is an effective way to prevent influenza infection, it is not clear if these conclusions are based on high quality SR methods. As such, we systematically identified, critically appraised, and summarised the characteristics and adherence to methodological standards in SRs with meta-analysis of efficacy/effectiveness of influenza vaccines.

METHODS

We searched MEDLINE, Embase, Scopus, CINAHL, Global Health, and CDSR for English-language SR publications up to July 11, 2022. We summarised the characteristics, adherence to methodological standards and SR quality (AMSTAR 2).

RESULTS

From 11,193 retrieved citations, we included 48 publications (47 SRs). Seventy-five percent were of a critically low quality, 19% of a low quality, 2% of a moderate quality, and 4% of a high quality. Thirteen percent were industry-funded, about 13% co-authored by industry employee(s), and 4% commissioned by an organisation or authority. Only 45% percent reported protocol registration, 6% reported collaboration with a knowledge synthesis librarian/information specialist, and 60% utilised a reporting checklist (e.g. PRISMA).

CONCLUSIONS AND RELEVANCE

SRs with meta-analysis of efficacy/effectiveness of influenza vaccines are mostly of critically low quality and even the more recent reviews did not follow current best SR practices. These findings are significant in view of the controversies that surround influenza vaccines, and the use of SRs in informed decision-making. However, the findings do not justify curtailment or cessation of influenza vaccine use as vaccines continue to offer substantial net public health benefit.HighlightsWe systematically identified, critically appraised, and summarised the characteristics and adherence to methodological standards in 47 systematic reviews with meta-analysis of efficacy/effectiveness of influenza vaccines.13% of the reviews were industry-funded.About 13% of the reviews were co-authored by industry employee(s).4% of the reviews were commissioned by an organisation/authority.45% of the reviews reported protocol registration.6% of the reviews reported collaborating with a knowledge synthesis librarian/information specialist to prepare the search strategy.60% of the reviews reported using the PRISMA (or similar) checklist.75% of the reviews were judged to be of critically low quality; 19% of low quality; 2% of moderate quality; 4% of high quality.

Vaccination for the Prevention of Infection among Immunocompromised Patients: A Concise Review of Recent Systematic Reviews

Vaccination is crucial for avoiding infection-associated morbidity and mortality among immunocompromised patients. However, immunocompromised patients respond less well to vaccinations compared to healthy people, and little is known about the relative efficacy of various vaccines among different immunocompromised states. A total of 54 systematic reviews (22 COVID-19; 32 non-COVID-19) published within the last 5 years in Pubmed® were reviewed. They demonstrated similar patterns within three seroconversion response categories: good (about >60% when compared to healthy controls), intermediate (~40−60%), and poor (about <40%). Good vaccine responses would be expected for patients with chronic kidney disease, human immunodeficiency virus infection (normal CD4 counts), immune-mediated inflammatory diseases, post-splenectomy states, and solid tumors. Intermediate vaccine responses would be expected for patients with anti-cytotoxic T-lymphocyte antigen-4 therapy, hematologic cancer, and human immunodeficiency virus infection (low CD4 counts). Poor vaccine responses would be expected for patients with B-cell-depleting agents (e.g., anti-CD20 therapy), hematopoietic stem-cell transplant, solid organ transplant, and liver cirrhosis. For all vaccine response categories, vaccination should be timed when patients are least immunosuppressed. For the intermediate and poor vaccine response categories, high-dose vaccine, revaccination when patients are less immunosuppressed, checking for seroconversion, additional booster doses, and long-acting monoclonal antibodies may be considered, supplemented by shielding measures.