The association between influenza vaccine effectiveness and egg-based manufacturing technology: literature review and US expert consensus.

BACKGROUND: Influenza is associated with significant disease burden in the US and is currently best controlled by vaccination programs. Influenza vaccine effectiveness (VE) is low and may be reduced by several factors, including egg adaptations. Although non-egg-based influenza vaccines reportedly have greater VE in egg-adapted seasons, evidence for egg adaptations' reduction of VE is indirect and dissociated, apart from two previous European consensuses. METHODS: This study replicated the methodology used in a 2020 literature review and European consensus, providing an updated review and consensus opinion of 10 US experts on the evidence for a mechanistic basis for reduction of VE due to egg-based manufacturing methods. A mechanistic basis was assumed if sufficient evidence was found for underlying principles proposed to give rise to such an effect. Evidence for each principle was brought forward from the 2020 review and identified here by structured literature review and expert panel. Experts rated the strength of support for each principle and a mechanistic basis for reduction of VE due to egg-based influenza vaccine manufacture in a consensus method (consensus for strong/very strong evidence = ≥ 3.5 on 5-point Likert scale). RESULTS: Experts assessed 251 references (from previous study: 185; this study: 66). The majority of references for all underlying principles were rated as strong or very strong supporting evidence (52-86%). Global surveillance, WHO candidate vaccine virus selection, and manufacturing stages involving eggs were identified as most likely to impact influenza VE. CONCLUSION: After review of extensive evidence for reduction of VE due to egg-based influenza vaccine manufacture, influenza experts in the US joined those in Europe in unanimous agreement for a mechanistic basis for the effect. Vaccine providers and administrators should consider use of non-egg-based influenza vaccine manufacture to reduce the risk of egg adaptations and likely impact on VE.

Estimation of Reduction in Influenza Vaccine Effectiveness Due to Egg-Adaptation Changes-Systematic Literature Review and Expert Consensus.

BACKGROUND: Influenza vaccines are the main tool to prevent morbidity and mortality of the disease; however, egg adaptations associated with the choice of the manufacturing process may reduce their effectiveness. This study aimed to estimate the impact of egg adaptations and antigenic drift on the effectiveness of trivalent (TIV) and quadrivalent (QIV) influenza vaccines. METHODS: Nine experts in influenza virology were recruited into a Delphi-style exercise. In the first round, the experts were asked to answer questions on the impact of antigenic drift and egg adaptations on vaccine match (VM) and influenza vaccine effectiveness (IVE). In the second round, the experts were presented with the data from a systematic literature review on the same subject and aggregated experts' responses to round one questions. The experts were asked to review and confirm or amend their responses before the final summary statistics were calculated. RESULTS: The experts estimated that, across Europe, the egg adaptations reduce, on average, VM to circulating viruses by 7-21% and reduce IVE by 4-16%. According to the experts, antigenic drift results in a similar impact on VM (8-24%) and IVE (5-20%). The highest reduction in IVE was estimated for the influenza virus A(H3N2) subtype for the under 65 age group. When asked about the frequency of the phenomena, the experts indicated that, on average, between the 2014 and 19 seasons, egg adaptation and antigenic drift were significant enough to impact IVE that occurred in two and three out of five seasons, respectively. They also agreed that this pattern is likely to reoccur in future seasons. CONCLUSIONS: Expert estimates suggest there is a potential for 9% on average (weighted average of "All strains" over three age groups adjusted by population size) and up to a 16% increase in IVE (against A(H3N2), the <65 age group) if egg adaptations that arise when employing the traditional egg-based manufacturing process are avoided.

The impact of candidate influenza virus and egg-based manufacture on vaccine effectiveness: Literature review and expert consensus.

INTRODUCTION: Influenza is associated with significant morbidity and mortality worldwide. Whilst vaccination is key for the prevention of influenza infection, there are many factors which may contribute to reduced vaccine effectiveness, including antigenic evolution via both antigenic drift and egg-adaptations. Due to the currently dissociated and indirect evidence supporting both the occurrence of these two phenomena in the egg-based manufacturing process and their effects on vaccine effectiveness, this topic remains a subject of debate. OBJECTIVE: To review the evidence and level of agreement in expert opinion supporting a mechanistic basis for reduced vaccine effectiveness due to egg-based manufacturing, using an expert consensus-based methodology and literature reviews. METHODS: Ten European influenza specialists were recruited to the expert panel. The overall research question was deconstructed into four component principles, which were examined in series using a novel, online, two-stage assessment of proportional group awareness and consensus. The first stage independently generated a list of supporting references for each component principle via literature searches and expert assessments. In the second stage, a summary of each reference was circulated amongst the experts, who rated their agreement that each reference supported the component principle on a 5-point Likert scale. Finally, the panel were asked if they agreed that, as a whole, the evidence supported a mechanistic basis for reduced vaccine effectiveness due to egg-based manufacturing. RESULTS: All component principles were reported to have a majority of strong or very strong supporting evidence (70-90%). CONCLUSIONS: On reviewing the evidence for all component principles, experts unanimously agreed that there is a mechanistic basis for reduced vaccine effectiveness resulting from candidate influenza virus variation due to egg-based manufacturing, particularly in the influenza A/H3N2 strain. Experts pointed to surveillance, candidate vaccine virus selection and manufacturing stages involving eggs as the most likely to impact vaccine effectiveness.

Cost-Effectiveness of Liraglutide Versus Dapagliflozin for the Treatment of Patients with Type 2 Diabetes Mellitus in the UK.

INTRODUCTION: To date there is a lack of economic analysis comparing glucagon-like peptide-1 receptor agonists (GLP-1RAs) to sodium-glucose co-transporter 2 inhibitors (SGLT-2i) for the treatment of type 2 diabetes mellitus (T2DM). Liraglutide and dapagliflozin are the most commonly prescribed GLP-1RA and SGLT-2i in the UK. This analysis investigated the cost-effectiveness of liraglutide 1.2 and 1.8 mg/day compared to dapagliflozin 10 mg/day for the treatment of T2DM in the UK in patients on dual and triple antidiabetic therapy. METHODS: Cost-effectiveness analysis was conducted in the QuintilesIMS CORE Diabetes Model (CDM). The model estimated expected costs and outcomes over a lifetime horizon using the UK national payer perspective. Liraglutide efficacy estimates and patient characteristics were sourced from a trial in patients on prior metformin monotherapy, and from a trial in patients on prior combination therapy. Comparative efficacy data for the other interventions were derived from a network meta-analysis. Utility inputs were extracted from a systematic literature review. Costs are presented in Great British Pound (GBP), 2016 values. RESULTS: In dual and triple therapy, liraglutide 1.2 mg was less costly and more effective compared with dapagliflozin 10 mg, providing a QALY gain of 0.04 and cost savings of GBP 11 per patient in dual therapy, and a QALY gain of 0.06 and cost savings of GBP 71 per patient in triple therapy. For liraglutide 1.8 mg, increased efficacy and costs compared with dapagliflozin 10 mg were observed in both dual and triple therapy. In dual therapy, a QALY gain of 0.07 and additional costs of GBP 888 per patient yielded an ICER of GBP 13,227, whereas in triple therapy a QALY gain of 0.07 and additional cost of GBP 791 per patient gave an ICER of 11,857. CONCLUSION: This long-term modelling analysis found that both dosages of liraglutide may be cost-effective treatment alternatives as part of a dual or a triple antidiabetic therapy in patients for whom an SGLT-2i therapy is considered. FUNDING: Novo Nordisk.

The cost-effectiveness of 5-FU-SA in the treatment of actinic keratoses of the face and scalp in the UK secondary care setting.

OBJECTIVE: The objective of this analysis was to estimate the relative cost-effectiveness of Actikerall 1 (5-FU-SA) vs cryotherapy in a secondary care setting in the UK, for lesion-directed treatment in patients with actinic keratoses (AK) of the face and scalp. METHODS: The model was a simple decision tree, with a 6-month time horizon. The perspective was that of the UK National Health Service (NHS). Modeled treatment effects included reported per-patient histological clearance and recurrence rates. Cost inputs comprised professional consultation time and cost of medication. Health-related utility estimation followed previously published methodology. Adverse events were not modeled. The key data and model structural assumptions followed expected UK practice. One-way and probabilistic sensitivity analyses were conducted to assess structural and parameter uncertainty. RESULTS: 5-FU-SA was found to be less costly (-£204) and more effective (+0.001 QALY) in base case and sensitivity analyses. In the probabilistic analysis there was 100% probability of being cost-effective over cryotherapy at £20,000 willingness to pay. Cost of professional time was a key driver of the model outcome. 5-FU-SA remained dominant across a range of scenario analyses, including exploration of assumptions around setting of care. LIMITATIONS: The time horizon of the analysis was short and data were not extrapolated beyond the duration of the clinical trial; however, this approach is consistent with likely follow-up of an AK patient. The clinical outcomes observed in the trial were based on a large proportion of cryotherapy patients undergoing an additional cycle of treatment; this may not occur or be required in an experienced secondary care setting. CONCLUSION: 5-FU-SA could be considered as a cost-effective choice for treatment of AK lesions of the face and scalp in secondary and mixed care settings in the UK. Use of 5-FU-SA in patients who would otherwise be managed with cryotherapy has the potential to result in cost savings.