Cost-effectiveness analysis of influenza and pneumococcal vaccination for Hong Kong elderly in long-term care facilities

BACKGROUND

To compare cost and quality-adjusted life-years (QALYs) gained by influenza vaccination with or without pneumococcal vaccination in the elderly living in long-term care facilities (LTCFs).

METHODS

Cost-effectiveness analysis based on Markov modelling over 5 years, from a Hong Kong public health provider's perspective, on a hypothetical cohort of LTCF residents aged > or = 65 years. Benefit-cost ratio (BCR) and net present value (NPV) of two vaccination strategies versus no vaccination were estimated. The cost and QALYs gained by two vaccination strategies were compared by Student's t-test in probabilistic sensitivity analysis (10,000 Monte Carlo simulations).

RESULTS

Both vaccination strategies had high BCRs and NPVs (6.39 and US$334 for influenza vaccination; 5.10 and US$332 for influenza plus pneumococcal vaccination). In base case analysis, the two vaccination strategies were expected to cost less and gain higher QALYs than no vaccination. In probabilistic sensitivity analysis, the cost of combined vaccination and influenza vaccination was significantly lower (p<0.001) than the cost of no vaccination. Both vaccination strategies gained significantly higher (p<0.001) QALYs than no vaccination. The QALYs gained by combined vaccination were significantly higher (p = 0.030) than those gained by influenza vaccination alone. The total cost of combined vaccination was significantly lower (p = 0.011) than that of influenza vaccination.

CONCLUSION

Influenza vaccination with or without pneumococcal vaccination appears to be less costly with higher QALYs gained than no vaccination, over a 5-year period, for elderly people living in LTCFs from the perspective of a Hong Kong public health organisation. Combined vaccination was more likely to gain higher QALYs with lower total cost than influenza vaccination alone.

Plasma inflammatory cytokines and chemokines in severe acute respiratory syndrome

Severe acute respiratory syndrome (SARS) is a recently emerged infectious disease caused by a novel coronavirus, but its immunopathological mechanisms have not yet been fully elucidated. We investigated changes in plasma T helper (Th) cell cytokines, inflammatory cytokines and chemokines in 20 patients diagnosed with SARS. Cytokine profile of SARS patients showed marked elevation of Th1 cytokine interferon (IFN)-gamma, inflammatory cytokines interleukin (IL)-1, IL-6 and IL-12 for at least 2 weeks after disease onset, but there was no significant elevation of inflammatory cytokine tumour necrosis factor (TNF)-alpha, anti-inflammatory cytokine IL-10, Th1 cytokine IL-2 and Th2 cytokine IL-4. The chemokine profile demonstrated significant elevation of neutrophil chemokine IL-8, monocyte chemoattractant protein-1 (MCP-1), and Th1 chemokine IFN-gamma-inducible protein-10 (IP-10). Corticosteroid reduced significantly IL-8, MCP-1 and IP-10 concentrations from 5 to 8 days after treatment (all P < 0.001). Together, the elevation of Th1 cytokine IFN-gamma, inflammatory cytokines IL-1, IL-6 and IL-12 and chemokines IL-8, MCP-1 and IP-10 confirmed the activation of Th1 cell-mediated immunity and hyperinnate inflammatory response in SARS through the accumulation of monocytes/macrophages and neutrophils.