Epidemiological Impact and Cost-Effectiveness of Varicella Vaccination Strategies in the United Kingdom

Abstract

Background Despite the burden of varicella, there is no universal varicella vaccination (UVV) programme in the United Kingdom (UK) due to concerns this could increase herpes zoster (HZ) incidence. This study assessed the cost-utility of a first-dose monovalent (V) or quadrivalent (MMRV) followed by a second-dose quadrivalent (MMRV) UVV programmes. GSK and MSD varicella-containing vaccines (VCVs) were considered. Methods A dynamic transmission and cost-effectiveness models were adapted to the UK. Outcomes measured included varicella and HZ incidences, the incremental cost-utility ratio (ICURs) over a lifetime horizon. The payer and societal perspectives were evaluated. Results The impact of V-MMRV and MMRV-MMRV UVV programmes on varicella incidence was comparable between both VCVs at equilibrium. HZ incidence increased by 1.6%-1.7% over seven years after UVV start, regardless of the strategies, then decreased by >95% at equilibrium. ICURs ranged from £5,665 (100 years) to £18,513 (20 years) per quality-adjusted life year (QALY) gained with V-MMRV; and from £9,220 to £27,101 per QALY gained with MMRV-MMRV (payer perspective). MMRV-MMRV was cost-effective in medium- and long-terms with GSK VCV, and only cost-effective at long-term with MSD VCV at £20,000 per QALY gained threshold. Without the exogenous boosting hypothesis, HZ incidence decreased through UVV implementation. ICURs were most sensitive to discount rates and MMRV price. Conclusions A 2-dose UVV was demonstrated to be a cost-effective alternative to no vaccination. With comparable effectiveness as MSD VCV at lower costs, GSK VCV may offer higher value for money.

Herpes Zoster in Children; Should the Varicella Vaccine be Administered as a Single Dose or a Double Dose?

“…Widespread use of the vaccine may reduce the circulating virus, leading to a decrease in cellular immunity in adults in later years, and thus undesirable consequences may cause such as an increased incidence of HZ. However, the incidence of HZ is expected to decrease, as vaccinated individuals in the long term are less likely to develop HZ compared to naturally infected individuals (7,12). In our study, the number of patients who had varicella vaccine was small, but the mean age of HZ in these patients was quite low compared to the population with the infection.…”

“…Because the risk in children with a history of varicella is much higher than in vaccinated children (6). Therefore, considering the lower reactivation rate of the vaccine strain in the long term, the incidence of HZ is expected to decrease (7). However, vaccination may reduce the opportunities for VZV immunity due to intermittent native varicella exposure, resulting in an increased incidence of HZ in older adults.…”

Modeling Cost-Effectiveness of Universal Varicella Vaccination With Different Varicella Vaccines in the United Kingdom

“…To the Editor—We read with interest the article by Akpo et al [ 1 ] comparing the cost-effectiveness of varicella vaccination in the United Kingdom (Varilrix, Priorix-Tetra, GSK, Belgium [V-GSK] and Varivax, ProQuad, Merck & Co, Inc, Kenilworth, NJ, USA [V-MSD]). This is an important contribution to the literature demonstrating value of varicella vaccination; however the use of predicted efficacy inputs for 1-dose V-MSD may not accurately reflect the actual vaccine performance and cost-effectiveness, considering availability of observed efficacy and effectiveness data.…”

“…The efficacy estimate reported [ 2 ] was based on antibody titer with predicted efficacy of 94.0% for all ages and 87.2% in younger children (n = 326; median age, 13 months). However, Akpo et al [ 1 ] used predicted efficacy of 78% from sensitivity analysis that was included to illustrate the impact of a 2-fold decrease in antibody titer on efficacy (from 88% to 78%) in children who were vaccinated at age 18 months.…”

“…Akpo et al [ 1 ] did not include the data showing higher efficacy of 1-dose V-MSD [ 3 ], with the rationale that this RCT was conducted in children aged 12 months to 12 years and noting that older children may experience a lower risk of infection. However, the average age in this RCT was 4.43 years, supporting efficacy in younger children.…”