Boyer

Publications

Hepatitis B Vaccination in Senegalese Children: Coverage, Timeliness, and Sociodemographic Determinants of Non-Adherence to Immunisation Schedules (ANRS 12356 AmBASS Survey)Journal articleLauren Perieres, Fabienne Marcellin, Gora Lo, Camelia Protopopescu, El Hadji Ba, Marion Coste, Coumba Toure Kane, Gwenaelle Maradan, Aldiouma Diallo, Cheikh Sokhna, et al., Vaccines, Volume 9, Issue 5, pp. 510, 2021

Detailed knowledge about hepatitis B virus (HBV) vaccination coverage and timeliness for sub-Saharan Africa is scarce. We used data from a community-based cross-sectional survey conducted in 2018–2019 in the area of Niakhar, Senegal, to estimate coverage, timeliness, and factors associated with non-adherence to the World Health Organisation-recommended vaccination schedules in children born in 2016 (year of the birth dose (BD) introduction in Senegal) and 2017–2018. Vaccination status was assessed from vaccination cards, surveillance data, and healthcare post vaccination records. Among 241 children with available data, for 2016 and 2017–2018, respectively, 31.0% and 66.8% received the BD within 24 h of birth (BD schedule), and 24.3% and 53.7% received the BD plus at least two pentavalent vaccine doses within the recommended timeframes (three-dose schedule). In logistic regression models, home birth, dry season birth, and birth in 2016 were all associated with non-adherence to the recommended BD and three-dose schedules. Living over three kilometres from the nearest healthcare post, being the firstborn, and living in an agriculturally poorer household were only associated with non-adherence to the three-dose schedule. The substantial proportion of children not vaccinated according to recommended schedules highlights the importance of considering vaccination timeliness when evaluating vaccination programme effectiveness. Outreach vaccination activities and incentives to bring children born at home to healthcare facilities within 24 h of birth, must be strengthened to improve timely HBV vaccination.

The value of specialist care—infectious disease specialist referrals—why and for whom? A retrospective cohort study in a French tertiary hospitalJournal articleManoj Sasikumar, Sylvie Boyer, Anne Remacle-Bonnet, Bruno Ventelou and Philippe Brouqui, European Journal of Clinical Microbiology & Infectious Diseases, Volume 36, Issue 4, pp. 625-633, 2017

This study evaluated the impact of infectious disease (ID) specialist referrals on outcomes in a tertiary hospital in France. This study tackled methodological constraints (selection bias, endogeneity) using instrumental variables (IV) methods in order to obtain a quasi-experimental design. In addition, we investigated whether certain characteristics of patients have a bearing on the impact of the intervention. We used the payments database and ID department files to obtain data for adults admitted with an ID diagnosis in the North Hospital, Marseille from 2012 to 2014. Comparable cohorts were obtained using coarsened exact matching and analysed using IV models. Mortality, readmissions, cost (payer perspective) and length of stay (LoS) were analysed. We recorded 15,393 (85.97%) stays, of which 2,159 (14.03%) benefited from IDP consultations. The intervention was seen to significantly lower the risk of inpatient mortality (marginal effect (M.E) = –19.06%) and cost of stay (average treatment effect (ATE) = – €5,573.39). The intervention group was seen to have a longer LoS (ATE = +4.95 days). The intervention conferred a higher reduction in mortality and cost for stays that experienced ICU care (mortality: odds ratio (OR) =0.09, M.E cost = –8,328.84 €) or had a higher severity of illness (mortality: OR=0.35, M.E cost = –1,331.92 €) and for patients aged between 50 and 65 years (mortality: OR=0.28, M.E cost = -874.78 €). This study shows that ID referrals are associated with lower risk of inpatient mortality and cost of stay, especially when targeted to certain subgroups.

How do supply-side factors influence informal payments for healthcare? The case of HIV patients in CameroonJournal articleHyacinthe T. Kankeu, Sylvie Boyer, Raoul A. Fodjo Toukam and Mohammad Abu-Zaineh, International Journal of Health Planning and Management, Volume 31, Issue 1, pp. 41-57, 2016

Direct out-of-pocket payments for health care continue to be a major source of health financing in low- and middle-income countries. Some of these direct payments take the form of informal charges paid by patients to access the needed health care services. Remarkably, however, little is known about the extent to which these payments are exercised and their determinants in the context of Sub-Saharan Africa. This study attempts therefore to shed light on the role of supply-side factors in the occurrence of informal payments while accounting for the demand-side factors. The study relies on data taken from a nationally representative survey conducted among people living with HIV/AIDS in Cameroon. A multilevel mixed-effects logistic model is employed to identify the factors associated with the incidence of informal payments. Results reveal that circa 3.05% of the surveyed patients incurred informal payments for the consultations made on the day of the survey. The amount paid informally represents up to four times the official tariff. Factors related to: (i) human resources management of the health facilities (e.g., task shifting); (ii) health professionals’ perceptions vis-à-vis the remunerations of HIV-care provision and (iii) reception of patients (e.g., waiting time) significantly influence the probability of incurring informal payments. Also of note, the type of health care facilities is found to play a role: informal payments appear to be significantly lower in private non-profit facilities compared to those belonging to public sector. Our findings allude to some policy recommendations than can help reduce the incidence of informal payments.

The Point-of-Care Laboratory in Clinical MicrobiologyJournal articleMichel Drancourt, Audrey Michel-Lepage, Sylvie Boyer and Didier Raoult, Clinical Microbiology Reviews, Volume 29, Issue 3, pp. 429-447, 2016

Point-of-care (POC) laboratories that deliver rapid diagnoses of infectious diseases were invented to balance the centralization of core laboratories. POC laboratories operate 24 h a day and 7 days a week to provide diagnoses within 2 h, largely based on immunochromatography and real-time PCR tests. In our experience, these tests are conveniently combined into syndrome-based kits that facilitate sampling, including self-sampling and test operations, as POC laboratories can be operated by trained operators who are not necessarily biologists. POC laboratories are a way of easily providing clinical microbiology testing for populations distant from laboratories in developing and developed countries and on ships. Modern Internet connections enable support from core laboratories. The cost-effectiveness of POC laboratories has been established for the rapid diagnosis of tuberculosis and sexually transmitted infections in both developed and developing countries.

Non-adherence to antiretroviral treatment and unplanned treatment interruption among people living with HIV/AIDS in Cameroon: Individual and healthcare supply-related factorsJournal articleSylvie Boyer, Isabelle Clerc, Cécile-Renée Bonono, Fabienne Marcellin, Paule-Christiane Bilé and Bruno Ventelou, Social Science & Medicine, Volume 72, Issue 8, pp. 1383-1392, 2011

In low-income countries, health system deficiencies may undermine treatment continuity and adherence to antiretroviral therapy (ART) that are crucial for the success of large-scale public ART programs. In addition to examining the effects of individual characteristics, on non-adherence to ART and treatment interruption behaviors - i.e. treatment interruption for more than 2 consecutive days during the previous 4 weeks, this study aims to extend our knowledge on the role played by healthcare supply-related characteristics in shaping these two treatment outcomes. These effects are examined using multilevel logistic models applied to a sub-sample of 2381 ART-treated patients followed-up in 27 treatment centers in Cameroon (ANRS-EVAL survey, 2006-2007). Multivariate models show that factors common to both non-adherence and treatment interruption include binge drinking (at the individual-level) and large hospital size (at the healthcare supply-level). Among the individual factors, financial difficulties of paying for HIV-care are the major correlates of treatment interruption [Adjusted Odds Ratio (AOR) 95% confidence interval (CI)Â =Â 11.73(7.24-19.00)]. By contrast, individual factors associated with an increased risk of non-adherence include: having a main partner but not living in a couple compared to patients living in a couple [AOR(95%CI)Â =Â 1.51(1.14-2.01)]; experience of discrimination in the family environment [AOR(95%CI)Â =Â 1.74(1.14-2.65)]; a lack of regular meals [AOR(95%CI)Â =Â 1.93(1.44-2.57)], and switching antiretroviral drugs (ARV) regimen [AOR(95%CI)Â =Â 1.36(1.08-1.70)]. At healthcare facility-level, the main correlate of ART interruption was antiretroviral stock-outs [AOR(95%CI)Â =Â 1.76(1.01-3.32)] whereas the lack of psychosocial support from specialized staff and lack of task-shifting to nurses in medical follow-up were both associated with a higher-risk of non-adherence [respective AOR (95%CI)Â =Â 2.81(1.13-6.95) and 1.51(1.00-3.40)

Does HIV services decentralization protect against the risk of catastrophic health expenditures?: some lessons from Cameroon.Journal articleSylvie Boyer, Mohammad Abu-Zaineh, Jérôme Blanche, Sandrine Loubiere, Cécile-Renée Bonono, Jean-Paul Moatti and Bruno Ventelou, Health services research, Volume 46, Issue 6pt2, pp. 2029-2056, 2011

OBJECTIVE: Scaling up antiretroviral treatment (ART) through decentralization of HIV care is increasingly recommended as a strategy toward ensuring equitable access to treatment. However, there have been hitherto few attempts to empirically examine the performance of this policy, and particularly its role in protecting against the risk of catastrophic health expenditures (CHE). This article therefore seeks to assess whether HIV care decentralization has a protective effect against the risk of CHE associated with HIV infection. DATA SOURCE AND STUDY DESIGN: We use primary data from the cross-sectional EVAL-ANRS

Individual and Structural Factors Associated With HIV Status Disclosure to Main Partner in Cameroon: ANRS 12-116 EVAL Survey, 2006-2007Journal articleMarie Suzan-Monti, Jérôme Blanche, Paule Bilé, Sinata Koulla-Shiro, Mohammad Abu-Zaineh, Fabienne Marcellin, Sylvie Boyer, Maria Patrizia Carrieri and Bruno Spire, JAIDS Journal of Acquired Immune Deficiency Syndromes, Volume 57, Issue Suppl. 1, pp. s22-s26, 2011

Encouraging HIV-positive people to disclose their serostatus to their main partner is considered as a key component of secondary prevention. The purpose of this study was to identify individual and structural factors associated with HIV serostatus disclosure to one's steady partner in Cameroon, a...

HIV disclosure and unsafe sex among HIV-infected women in Cameroon: Results from the ANRS-EVAL studyJournal articleSandrine Loubiere, Patrick Peretti-Watel, Sylvie Boyer, Jérôme Blanche, Séverin-Cécile Abega and Bruno Spire, Social Science & Medicine, Volume 69, Issue 6, pp. 885-891, 2009

Encouraging seropositive people to voluntarily disclose their serostatus has been promoted as a key component of HIV prevention. Among other reasons, HIV disclosure to one's main partner is believed to be an incentive for serodiscordant couples to practice safe sex. The present article investigated this issue by conducting a cross-sectional survey of a large sample of HIV-infected women attending HIV care centers in Cameroon (NÂ =Â 1014). Overall, 86.3% of these women had disclosed their serostatus to their main partner. With respect to sexual activity with their main partner during the previous three months, 35.0% had practiced abstinence and 47.4% only safe sex, whereas 17.6% had engaged in unsafe sex at least once. HIV disclosure to one's main partner was related to safe sexual practices in multivariate analysis. Some of the factors associated with disclosure and safe sex were illustrative of the positive roles of improved access to care and women's empowerment. On the contrary, beliefs overestimating the effectiveness of antiretroviral therapies were quite widespread among respondents and predictive of both concealment of HIV status and unsafe sex.

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 n/a, Issue n/a, Forthcoming

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.

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 n/a, Issue n/a, Forthcoming

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.