Assessment of potential public health impact of a quadrivalent inactivated influenza vaccine inThailand

Abstract

BackgroundEach year, an influenza B strain representing only one influenza B lineage is included in the trivalent inactivated influenza vaccine (IIV3); a mismatch between the selected lineage and circulating viruses can result in suboptimal vaccine effectiveness. We modeled the added potential public health impact of a quadrivalent inactivated influenza vaccine (IIV4) that includes strains from both influenza B lineages compared to IIV3 on influenza‐associated morbidity and mortality in Thailand.MethodsUsing data on the incidence of influenza‐associated hospitalizations and deaths, vaccine effectiveness, and vaccine coverage from the 2007–2012 influenza seasons in Thailand, we estimated rates of influenza‐associated outcomes that might be averted using IIV4 instead of IIV3. We then applied these rates to national population estimates to calculate averted illnesses, hospitalizations, and deaths for each season. We assumed that the influenza B lineage included in IIV3 would provide a relative vaccine effectiveness of 75% against the other B lineage.ResultsCompared to use of IIV3, use of IIV4 might have led to an additional reduction ranging from 0·4 to 14·3 influenza‐associated illnesses per 100 000 population/year, <0·1 to 0·5 hospitalizations per 100 000/year, and <0·1 to 0·4 deaths per 1000/year. Based on extrapolation to national population estimates, replacement of IIV3 with IIV4 might have averted an additional 267–9784 influenza‐associated illnesses, 9–320 hospitalizations, and 0–3 deaths.ConclusionCompared to use of IIV3, IIV4 has the potential to further reduce the burden of influenza‐associated morbidity and mortality in Thailand.

Costs per DALYs Averted of Quadrivalent Influenza Vaccine versus Trivalent Influenza Vaccine in Elderly Population in Thailand

“…[41][42][43][44][45][46] Previous studies did not provide an effective report of the QIV in the Thais. However, similar analyses on the effectiveness of QIV data were collected from Kittikraisak W, et al 9 and other studies from numerous countries. These data declare that the different rate of effectiveness between QIV and TIV is 0.16-4.6%.…”

“…These data declare that the different rate of effectiveness between QIV and TIV is 0.16-4.6%. 9,17,41,43,47,48 However, vaccine effectiveness may be lower in Southeast Asia, and much lower in mass immunization campaign than in randomized trials. 49 In this study, the probabilistic sensitivity analysis (PSA) was done to reduce of an absence of reliable data.…”

“…QIV provides coverage and protection against the TIV-mismatched influenza B lineage. 9 Currently, the United States, Canada, Australia and the United Kingdom recommend QIV. 10 The efficacy of QIV (immune response) is 70% and TIV is 59%.…”

“…26,27 In Thailand, QIV is recommended as an alternative to TIV, but is more costly. 9 Also, hitherto now, a study had not been conducted comparing the cost-effectiveness of QIV and TIV. This study evaluated the cost-effectiveness between QIV and TIV from a societal perspective in Thai people ages 60 and over.…”