Publications

La plupart des informations présentées ci-dessous ont été récupérées via RePEc avec l'aimable autorisation de Christian Zimmermann
Sibling status, home birth, tattoos and stitches are risk factors for chronic hepatitis B virus infection in Senegalese children: A cross-sectional surveyJournal articleLauren Perieres, Camelia Protopopescu, Gora Lo, Fabienne Marcellin, El Hadji Ba, Marion Coste, Coumba Toure Kane, Aldiouma Diallo, Cheikh Sokhna, Sylvie Boyer, et al., Journal of Viral Hepatitis, Volume 28, Issue 11, pp. 1515-1525, 2021

Sub-Saharan Africa's hepatitis B virus (HBV) burden is primarily due to infection in infancy. However, data on chronic HBV infection prevalence and associated risk factors in children born post-HBV vaccination introduction are scarce. We estimated hepatitis B surface antigen (HBsAg) prevalence and risk factors in Senegalese children born during the HBV vaccination era. In 2018–2019, a community-based cross-sectional survey was conducted in Senegal among children born between 2004 and 2015 (ie after the three-dose HBV vaccine series was introduced (2004) but before the birth dose's introduction (2016)). HBsAg-positive children were identified using dried blood spots. A standardized questionnaire collected socioeconomic information. Data were age-sex weighted and calibrated to be representative of children living in the study area. Risk factors associated with HBsAg positivity were identified using negative binomial regression. Among 1,327 children, 17 were HBsAg-positive (prevalence = 1.23% (95% confidence interval [CI] 0.61–1.85)). Older age (adjusted incidence-rate ratio [aIRR] 1.31 per one-year increase, 95% CI 1.10–1.57), home vs healthcare facility delivery (aIRR 3.55, 95% CI 1.39–9.02), stitches (lifetime) (aIRR 4.79; 95% CI 1.84–12.39), tattoos (aIRR 8.97, 95% CI 1.01–79.11) and having an HBsAg-positive sibling with the same mother (aIRR 3.05, 95% CI 1.09–8.57) were all independently associated with HBsAg positivity. The low HBsAg prevalence highlights the success of the Senegalese HBV vaccination program. To further reduce HBV acquisition in children, high-risk groups, including pregnant women and siblings of HBsAg-positive individuals, must be screened. Vital HBV infection prevention measures include promoting delivery in healthcare facilities, and increasing awareness of prevention and control procedures.

Long-run stability of money demand and monetary policy: The case of AlgeriaJournal articleRaouf Boucekkine, Mohammed Laksaci et Mohamed Touati-Tliba, The Journal of Economic Asymmetries, Volume 24, pp. e00217, 2021

Since the start of the oil counter-shock in June 2014, Algeria has experienced unprecedented twin deficits. The excessive monetisation of the public deficit coupled with other deep anomalies in the economy of this country acutely calls for reconsideration of its monetary policy. To this end a prior study of the long-run stability of money demand is needed. We estimate the demand for money for monetary aggregates M1 and M2, and cash in Algeria over the period 1979–2019, and study its long-run stability. We show that the transaction motive is significant for all three aggregates, especially for the demand for cash, reflecting the weight of informal economy “practices”. The elasticity of the scale variable is very close to unity for M2 and M1, and even equal to unity for cash demand (1.006). The elasticity of inflation is also significant for all three aggregates, although its level is higher in the case of cash demand (−6.474). Despite the persistence of certain financial repression mechanisms, interest rate elasticity is significant for all three aggregates, but higher for M1 and cash. The same observation is made for elasticity of the exchange rate, reflecting the effect of monetary substitution, especially for M1 and cash. Finally, our study concludes that the demand for money in terms of M1 remains stable, the same observation being confirmed for the M2 aggregate. However, the demand for fiat currency proves not to be stable. The consequences for the optimal design of monetary policy in Algeria are clearly stated.

Physicians’ incentives to adopt personalised medicine: Experimental evidenceJournal articleDavid Bardey, Samuel Kembou et Bruno Ventelou, Journal of Economic Behavior & Organization, Volume 191, pp. 686-713, 2021

We study physicians’ incentives to use personalised medicine techniques, replicating the physician’s trade-offs under the option of personalised medicine information. In a laboratory experiment conducted in two French Universities, prospective physicians played a real-effort game. We vary both the information structure (free access versus paid access to personalised medicine information) and the payment scheme (pay-for-performance (P4P), capitation (CAP) and fee-for-service (FFS)), implementing a within-subject design. Our results are threefold: (i) Compared to FFS and CAP, the P4P scheme strongly and positively impacts the decision to adopt personalised medicine. (ii) Although expected to dominate the other schemes, P4P is not always efficient in transforming free access to personalised medicine into higher quality of care. (iii) When it has to be paid for and after controlling for self-selection, personalised medicine is positively associated with quality, suggesting that subjects tend to make better use of information that comes at a cost. We find this effect to be stronger for males than for females prospective physicians. Quantification of our results however suggests that this positive impact is not strong enough to justify generalising the payment for personalised medicine access. Finally, we develop a theoretical model that includes in its set-up a commitment device component, which is the mechanism that we inferred from the data of the experiment. Our model replicates the principal results of the experiment, reinforcing the interpretation that the higher quality provided by subjects who bought personalised medicine can be interpreted as a commitment device effect.

Evidence-based policymaking when evidence is incomplete: The case of HIV programme integrationJournal articleJan A. C. Hontelez, Caroline A. Bulstra, Anna Yakusik, Erik Lamontagne, Till W. Bärnighausen et Rifat Atun, PLOS Medicine, Volume 18, Issue 11, pp. e1003835, 2021

Jan Hontelez and co-authors discuss the use of different types of evidence to inform HIV program integration.

Economic Aspects of Settlement in the Oasis of Bukhara, Uzbekistan: An Archaeo-Economic ApproachJournal articleRocco Rante et Federico Trionfetti, Cambridge Archaeological Journal, Volume 31, Issue 4, pp. 581-596, 2021

This paper focuses on the new approach studying variations in city size and the impact that the Silk Road had on the structure of cities, demonstrated through the study of economic aspects of the Bukhara oasis. We use archaeological data, compare the ancient economy to modern ones, use modern economic theory and methods to understand ancient society, and use what we have learned about the ancient economy to understand modern economies better. In sum, we explore the past through the present and the latter through the former. Our main finding is the generation of models able to answer to the city-size distribution in different territories, comparing them between the past and the present. This study first revealed that, through Zipf's Law, we found similarities between modern post-Industrial Revolution and medieval economics. Secondly, we also found that in ancient times the structure of the city was linked with the local economic demand. We have demonstrated this through the study of cities along the Silk Road.

Transitory and permanent shocks in the global market for crude oilJournal articleNooman Rebei et Rashid Sbia, Journal of Applied Econometrics, Volume 36, Issue 7, pp. 1047-1064, 2021

This paper documents the determinants of real oil price in the global market based on an empirical model embedding transitory and permanent shocks. We find evidence of significant differences in the propagation mechanisms of transitory versus permanent disturbances, pointing to the importance of disentangling their distinct effects. Permanent supply shocks are found to be very influential in driving oil price fluctuations.

Pollution and growth: The role of pension in the efficiency of health and environmental policiesJournal articleArmel Ngami et Thomas Seegmuller, International Journal of Economic Theory, Volume 17, Issue 4, pp. 390-415, 2021

This paper analyzes the effect of a pay-as-you-go pension system on the evolution of capital and pollution, and on the efficiency of an environmental versus health policy. In an overlapping generations model, we introduce endogenous longevity that depends on pollution and health expenditures. Global dynamics may display multiple balanced growth paths (BGPs). We show that by discouraging savings, a policy that promotes the pension system enlarges the environmental poverty trap. More surprisingly, the environmental policy has contrasting effects according to the significance of the pension system. If it has a small size, a more environmentally-friendly policy enlarges the environmental poverty trap and leads to a rise in capital over pollution at the highest stationary equilibrium. In contrast, in economies where intergenerational solidarity is well developed, capital over pollution decreases at the highest BGP. In such a case, the environmental policy does not necessarily lead to a better longevity and growth.

Integrating HIV services and other health services: A systematic review and meta-analysisJournal articleCaroline A. Bulstra, Jan A. C. Hontelez, Moritz Otto, Anna Stepanova, Erik Lamontagne, Anna Yakusik, Wafaa M. El-Sadr, Tsitsi Apollo, Miriam Rabkin, UNAIDS Expert Gro Integration, et al., PLOS Medicine, Volume 18, Issue 11, pp. e1003836, 2021

Background
Integration of HIV services with other health services has been proposed as an important strategy to boost the sustainability of the global HIV response. We conducted a systematic and comprehensive synthesis of the existing scientific evidence on the impact of service integration on the HIV care cascade, health outcomes, and cost-effectiveness.

Methods and findings
We reviewed the global quantitative empirical evidence on integration published between 1 January 2010 and 10 September 2021. We included experimental and observational studies that featured both an integration intervention and a comparator in our review. Of the 7,118 unique peer-reviewed English-language studies that our search algorithm identified, 114 met all of our selection criteria for data extraction. Most of the studies (90) were conducted in sub-Saharan Africa, primarily in East Africa (55) and Southern Africa (24). The most common forms of integration were (i) HIV testing and counselling added to non-HIV services and (ii) non-HIV services added to antiretroviral therapy (ART). The most commonly integrated non-HIV services were maternal and child healthcare, tuberculosis testing and treatment, primary healthcare, family planning, and sexual and reproductive health services. Values for HIV care cascade outcomes tended to be better in integrated services: uptake of HIV testing and counselling (pooled risk ratio [RR] across 37 studies: 1.67 [95% CI 1.41–1.99], p < 0.001), ART initiation coverage (pooled RR across 19 studies: 1.42 [95% CI 1.16–1.75], p = 0.002), time until ART initiation (pooled RR across 5 studies: 0.45 [95% CI 0.20–1.00], p = 0.050), retention in HIV care (pooled RR across 19 studies: 1.68 [95% CI 1.05–2.69], p = 0.031), and viral suppression (pooled RR across 9 studies: 1.19 [95% CI 1.03–1.37], p = 0.025). Also, treatment success for non-HIV-related diseases and conditions and the uptake of non-HIV services were commonly higher in integrated services. We did not find any significant differences for the following outcomes in our meta-analyses: HIV testing yield, ART adherence, HIV-free survival among infants, and HIV and non-HIV mortality. We could not conduct meta-analyses for several outcomes (HIV infections averted, costs, and cost-effectiveness), because our systematic review did not identify sufficient poolable studies. Study limitations included possible publication bias of studies with significant or favourable findings and comparatively weak evidence from some world regions and on integration of services for key populations in the HIV response.

Conclusions
Integration of HIV services and other health services tends to improve health and health systems outcomes. Despite some scientific limitations, the global evidence shows that service integration can be a valuable strategy to boost the sustainability of the HIV response and contribute to the goal of ‘ending AIDS by 2030’, while simultaneously supporting progress towards universal health coverage.

Political Connections and White-Collar Crime: Evidence from Insider Trading in FranceJournal articleThomas Bourveau, Renaud Coulomb et Marc Sangnier, Journal of the European Economic Association, Volume 19, Issue 5, pp. 2543-2576, 2021

This paper investigates whether political connections affect individuals’ propensity to engage in white-collar crime. We identify connections by campaign donations or direct friendships and use the 2007 French Presidential election as a marker of change in the value of political connections to the winning candidate. We compare the behavior of Directors of publicly listed companies who were connected to the future President to the behavior of other non-connected Directors, before and after the election. Consistent with the belief that connections to a powerful politician can protect someone from prosecution or punishment, we uncover indirect evidence that connected Directors are more likely to engage in suspicious insider trading after the election: Purchases by connected Directors trigger larger abnormal returns, connected Directors are less likely to comply with trading disclosure requirements in a timely fashion, and connected Directors trade closer in time to their firms’ announcements of results. (JEL: D72, G14, G18, G38, K22, K42)

The Welfare Consequences of Centralization: Evidence from a Quasi-Natural Experiment in SwitzerlandJournal articleSarah Flèche, Review of Economics and Statistics, Volume 103, Issue 4, pp. 621–635, 2021

Many countries are reallocating tasks and powers to more central levels of government. To identify centralization’s welfare effects, I use a difference-in-differences design that relies on time and cross-cantonal variation in the implementation of centralization reforms in Switzerland. I find that centralization provokes significant decreases in residents’ life satisfaction. I identify one mechanism driving the effect, namely the procedural disutility that individuals experience from having less influence over the formulation of political decisions. This effect is largest among individuals with higher expected benefits from being involved in the political decision process, with detrimental effects on local political participation.