Emmanouil Noikokyris

Ecological validity of cost-effectiveness models of universal HPV vaccination: A systematic literature review

BACKGROUND The protective (herd) effect of the selective vaccination of pubertal girls against human papillomavirus (HPV) implies a high probability that one of the two partners involved in intercourse is immunised, hence preventing the other from this sexually transmitted infection. The dynamic transmission models used to inform immunisation policy should include consideration of sexual behaviours and population mixing in order to demonstrate an ecological validity, whereby the scenarios modelled remain faithful to the real-life social and cultural context. The primary aim of this review is to test the ecological validity of the universal HPV vaccination cost-effectiveness modelling available in the published literature. METHODS The research protocol related to this systematic review has been registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42016034145). Eight published economic evaluations were reviewed. RESULTS None of the studies showed due consideration of the complexities of human sexual behaviour and the impact this may have on the transmission of HPV. DISCUSSION Our findings indicate that all the included models might be affected by a different degree of ecological bias, which implies an inability to reflect the natural demographic and behavioural trends in their outcomes and, consequently, to accurately inform public healthcare policy. In particular, ecological bias have the effect to over-estimate the preference-based outcomes of selective immunisation. A relatively small (15-20%) over-estimation of quality-adjusted life years (QALYs) gained with selective immunisation programmes could induce a significant error in the estimate of cost-effectiveness of universal immunisation, by inflating its incremental cost effectiveness ratio (ICER) beyond the acceptability threshold. The results modelled here demonstrate the limitations of the cost-effectiveness studies for HPV vaccination, and highlight the concern that public healthcare policy might have been built upon incomplete studies.

Ecological validity of cost-effectiveness models of universal HPV vaccination: a protocol for a systematic review

BackgroundSexually transmitted infection with high-risk, oncogenic strains of human papillomavirus (HPV) still induces a relevant burden of diseases on both men and women. Although vaccines appear to be highly efficacious in preventing the infection of the most common high-risk strains (HPV 6, 11, 16, 18), important questions regarding the appropriate target population for prophylactic vaccination are still debated. Models in the extant literature seem to converge on the cost-effectiveness of high coverage (>80%) of a single cohort of 12-year-old girls. This vaccination strategy should provide an adequate level of indirect protection (herd immunity) to the unvaccinated boys. This argument presupposes the ecological validity of the cost-effectiveness models; the implicit condition that the characteristics of the individuals and the sexual behaviours observed in the models is generalisable to the natural behaviours of the population.The primary aim of this review is to test the ecological validity of the cost-effectiveness models of universal HPV vaccination available in the literature. The ecological validity of each model will be defined by the number of representative characteristics and behaviours taken into consideration.MethodsNine bibliographic databases will be searched: MEDLINE (via PubMed); Scopus; Science Direct; EMBASE via OVID SP, Web of Science, DARE, NHIR EED and HTA (via NHIR CRD); and CINHAL Plus. An additional search for grey literature will be conducted on Google Scholar and Open Grey. A search strategy will be developed for each of the databases. Data will be extracted following a pre-determined spreadsheet and then clustered and prioritised: the main outcomes will report the inputs to the demographic and epidemiological model, while additional outcomes will refer to basic inputs to the cost-effectiveness valuation.Each study included in the review will be scored by the number of representative characteristics and behaviours taken into consideration (yes or no) on both dimensions. Individual study’s scores will be plotted in a 2 by 2 matrix: studies included in the upper right quadrant will be defined as ecologically valid, since which both individuals’ characteristics and their sexual behaviours are representative.DiscussionThe proposed systematic review will be the first to assess the ecological validity of cost-effectiveness studies. In the context of sexually transmitted diseases, when this condition is violated, an error in predicting the protective impact of herd immunity would occur. Hence, a vaccination policy informed on ecologically invalid models would potentially expose boys to a residual risk of contracting HPV-induced malignancies.Systematic review registrationPROSPERO CRD42016034145

What is the Impact of Investment on Labor Income

This study investigates empirically the determinants of labor shares focusing on the role of investment and exchange rate volatility. The authors use a system GMM panel approach and consider 34 Organization for Economic Co-operation and Development (OECD) countries along with South Africa for the period 1995-2015. The authors results reveal that the level of a country’s investment is a significant factor driving changes in the labor share of income. This evidence is in line with the theoretical mechanism for the role of investment presented by Lawrence (2015). While the authors consider several other factors, suggested by the extant empirical literature, the authors only find evidence for the degree of a country’s exposure to the international financial system, which is inversely related with labor shares. This study is a background note for the South Africa systematic country diagnostic.

QUANTITATIVE EASING AND THE UK STOCK MARKET: DOES THE BANK OF ENGLAND INFORMATION DISSEMINATION STRATEGY MATTER?: QE AND THE UK STOCK MARKET

We use intraday aggregate stock market data and an event‐study framework to assess the UKs equity market reaction to the unexpected element of the Bank of England Monetary Policy Committees (MPC) asset purchase announcements for the 2009–2017 period. We assess the reactions of equity returns and their volatility over various time frames, both preceding and following the MPC announcements. Our results show that the UK unconventional monetary policy shocks have a significant impact on domestic equity returns and volatilities. The strength of this impact depends on the Banks information dissemination through inflation reports and the publication of the MPCs voting records. (JEL G14, E44, E52)