Cost-effectiveness of varicella and herpes zoster vaccination in Sweden: An economic evaluation using a dynamic transmission model

Abstract

Objectives Comprehensive cost-effectiveness analyses of introducing varicella and/or herpes zoster vaccination in the Swedish national vaccination programme. Design Cost-effectiveness analyses based on epidemiological results from a specifically developed transmission model. Setting National vaccination programme in Sweden, over an 85- or 20-year time horizon depending on the vaccination strategy. Participants Hypothetical cohorts of people aged 12 months and 65-years at baseline. Interventions Four alternative vaccination strategies; 1, not to vaccinate; 2, varicella vaccination with one dose of the live attenuated vaccine at age 12 months and a second dose at age 18 months; 3, herpes zoster vaccination with one dose of the live attenuated vaccine at 65 years of age; and 4, both vaccine against varicella and herpes zoster with the before-mentioned strategies. Main outcome measures Accumulated cost and quality-adjusted life years (QALY) for each strategy, and incremental cost-effectiveness ratios (ICER). Results It would be cost-effective to vaccinate against varicella (dominant), but not to vaccinate against herpes zoster (ICER of EUR 200,000), assuming a cost-effectiveness threshold of EUR 50,000 per QALY. The incremental analysis between varicella vaccination only and the combined programme results in a cost per gained QALY of almost EUR 1.6 million. Conclusions The results from this study are central components for policy-relevant decision-making, and suggest that it was cost-effective to introduce varicella vaccination in Sweden, whereas herpes zoster vaccination with the live attenuated vaccine for the elderly was not cost-effective–the health effects of the latter vaccination cannot be considered reasonable in relation to its costs. Future observational and surveillance studies are needed to make reasonable predictions on how boosting affects the herpes zoster incidence in the population, and thus the cost-effectiveness of a vaccination programme against varicella. Also, the link between herpes zoster and sequelae need to be studied in more detail to include it suitably in health economic evaluations.

Systematic review of economic evaluations of varicella vaccination programmes

“…The majority of studies, 53, focused on universal childhood vaccination at about 12–15 months for the first dose, up to 6 years for the second if any. Thirty-four used a dynamic model, 21 of which reported incremental cost per QALY values [ 27 , 28 , 50 , 51 , 53 – 56 , 59 , 62 – 64 , 68 , 81 – 88 ]. These studies tended to be the most recently published, with an average publication date of 2015.…”

“…To address current concerns in childhood vaccination, a range of issues were covered, singly or in various combinations: the effect of taking account of HZ [ 47 , 50 , 53 , 54 , 56 , 59 , 63 , 81 – 83 , 87 , 88 ], the effect of boosting [ 50 , 59 , 81 ], age at second dose [ 53 , 55 ], confining a universal programme to susceptible adolescents [ 64 ], or post exposure prophylaxis [ 31 ]. Some of the studies measuring QALYs focused on simpler issues: a standard programme without herd immunity or HZ [ 68 ], with a package including catchup [ 63 ], with measles, mumps and rubella (MMR) vaccine [ 84 , 85 ] or a simple two dose childhood programme [ 81 ].…”

“…Others, having compared incremental cost per QALY results with a local threshold of acceptable cost per QALY, reported whether the threshold had been satisfied or not [ 51 , 53 , 56 , 58 , 59 , 61 , 64 , 68 , 87 ]. Yet others reported whether there was a dominant option in the sense of having a higher level of QALYs and lower cost than a comparator [ 16 , 53 , 54 , 57 , 59 , 62 , 65 , 81 , 83 , 84 , 88 ]. There were examples of disparate findings emerging from studies which apparently have much in common [ 59 , 64 ].…”

“…We review these studies in publication order starting with the most recent. Heininger et al (2021), Pawaskar et al (2021) and Wolff (2021) reported that taking account of the effects of herpes zoster would not compromise the cost-effectiveness of varicella vaccination [ 51 , 62 , 88 ], whereas Rafftery et al (2021) reported that, on certain assumptions, it might [ 55 ]. Azzari et al (2020) reported that universal childhood vaccination dominates [ 81 ].…”

The Long-Term Clinical and Economic Impact of Universal Varicella Vaccination in Slovenia

“…Introducing a 2-dose strategy into national vaccination programs in Sweden reduced annual cases from 120 000 to less than 300 across all age groups and was cost-effective compared with no vaccination from the societal and payer perspectives. 37 A significant reduction in cases was also predicted following the introduction of UVV in Turkey, where 2-dose vaccination was cost-effective. 23 In Italy, the introduction of 2-dose UVV was predicted to have a major impact on reducing varicella incidence, prevalence, and societal costs, and all strategies assessed were cost-saving vs no vaccination.…”