Papers by David Gisselquist
JAIDS Journal of Acquired Immune Deficiency Syndromes, 2001
Future Virology, 2010
Evaluation of: Wawer MJ, Makumbi F, Kigozi G et al.: Circumcision in HIV-infected men and its eff... more Evaluation of: Wawer MJ, Makumbi F, Kigozi G et al.: Circumcision in HIV-infected men and its effect on HIV transmission to female partners in Rakai, Uganda: a randomized controlled trial. Lancet 374, 229–237 (2009). A randomized, controlled trial (RCT) testing the hypothesis that circumcision in HIV-infected men would reduce HIV transmission to uninfected female sexual partners failed to confirm such findings from observational studies in Africa. Researchers noted no statistically significant differences in incident HIV to partners of circumcised or uncircumcised HIV-infected men. Surprisingly, by the time the trial was terminated because of futility, the trend was toward higher incidence in partners of circumcised men. The trial may have been stopped too early to adequately assess this unexpected trend. Since the investigators focused exclusively on sexual transmission, it is possible, if not likely, that unmeasured nonsexual (unsanitary puncturing) exposures caused some incident ...
The Journal of Infectious Diseases, 2005
in stem cell transplant recipients receiving voriconazole. Clin Infect Dis 2004; 39:743-6. 4. Siw... more in stem cell transplant recipients receiving voriconazole. Clin Infect Dis 2004; 39:743-6. 4. Siwek GT, Dodgson KJ, de Magalhaes-Silverman M, et al. Invasive zygomycosis in hematopoietic stem cell transplant recipients receiving voriconazole prophylaxis. Clin Infect Dis 2004; 39:584-7. 5. Kauffman CA. Zygomycosis: reemergence of an old pathogen. Clin Infect Dis 2004; 39:588-90. 6. Kontoyiannis DP, Lionakis MS, Lewis RE, et al. Zygomycosis in a tertiary-care cancer center in the era of Aspergillus-active antifungal therapy: a case-control observational study of 27 recent cases. J Infect Dis 2005; 191:1350-60. 7. Slavin MA, Osborne B, Adams R, et al. Efficacy and safety of fluconazole prophylaxis for fungal infections after marrow transplantationa prospective, randomized, double-blind study. J Infect Dis 1995; 171:1545-52. 8. Winston DJ, Maziarz RT, Chandrasekar PH, et al. Intravenous and oral itraconazole versus intravenous and oral fluconazole for long-term antifungal prophylaxis in allogeneic hematopoietic stem-cell transplant recipients: a multicenter, randomized trial.
South African Medical Journal, Feb 1, 2004
This study is based on surveys of private-sector innovation and research in Kenya,
SSRN Electronic Journal, 2013
ABSTRACT Under the Comprehensive Africa Agriculture Development Programme (CAADP) the African Uni... more ABSTRACT Under the Comprehensive Africa Agriculture Development Programme (CAADP) the African Union proposes 6 percent annual growth in agricultural production, of which more than half is to come from productivity growth. However, the recent rate at which new varieties (including hybrids) are being introduced – less than one per country per crop per year for food field crops in most countries in sub-Saharan Africa – is too low to achieve such growth. Low rates of variety introduction can be traced to government controls involving variety performance tests and fees followed by government committees deciding if varieties will be useful for farmers and therefore permitted for seed sales. Because governments do not consider all the factors that farmers might appreciate in a variety, these procedures deny farmers access to useful varieties. The time, cost, and uncertainty involved in these procedures discourage private companies from introducing new varieties, especially for crops and countries with small markets. In countries without such controls – including South Africa and many low to high income countries outside Africa – farmers have access to much larger flows of new varieties. African governments could open the door to much larger flows of new varieties by making variety registration optional or automatic and very low cost or free.
A nosocomial HIV outbreak recognized in late 2014 in Roka commune, Cambodia, demonstrates the pot... more A nosocomial HIV outbreak recognized in late 2014 in Roka commune, Cambodia, demonstrates the potential for rapid transmission through skin-piercing healthcare procedures. Information reported from the investigation of the Roka commune outbreak is sufficient to estimate the transmission efficiency of HIV through contaminated injection equipment. With conservative assumptions, two estimates are 4.6% and 9.2%. These estimates are much greater than widely disseminated and influential low estimates of risk from unsafe injections, estimates which have encouraged low estimates of the contribution of unsafe healthcare to Africa's generalized HIV epidemics. More information about nosocomial risks in Roka commune could improve the estimates in this paper and advise HIV prevention programs, particularly in countries with unreliably sterile healthcare and high HIV prevalence.
African fisherfolk suffering from HIV are subject to stigma, denigration and disempowerment, all ... more African fisherfolk suffering from HIV are subject to stigma, denigration and disempowerment, all of which weaken their voice in civil society...
Abdool Karim and colleagues demonstrated that vaginal tenofovir gel provides partial protection a... more Abdool Karim and colleagues demonstrated that vaginal tenofovir gel provides partial protection against HIV in South African women. However, the study design of their double-blind, randomized, placebo-controlled CAPRISA 004 trial did not allow for determining the mode of HIV acquisition for participants with incident infection. The available evidence suggests substantial nonsexual transmission. Trial participants' reported exposure to HIV through penile-vaginal sex, at the aggregate level, was unrelated to HIV incidence over time. Moreover, the CAPRISA 004 trial data imply a questionably high nominal per act transmission probability for coital acts without a condom (1.8% in the tenofovir gel arm and 3.0% in the placebo arm). Based on the results of dosing studies, the vaginal tenofovir gel appears to be a somewhat inefficient vehicle for delivering tenofovir systemically, thereby serving to prevent HIV acquisition from either blood or sexual exposures. Further analysis of the trial data and making the full trial protocol and data public would allow competing interpretations of the CAPRISA 004 results to be investigated. New trials that include critical design features for determining modes of HIV transmission would provide the most definitive evidence.
SSRN Electronic Journal, 2019
Contraception, 2008
To the Editor: In a recent article Leclerc et al. use data from the Demographic and Health Survey... more To the Editor: In a recent article Leclerc et al. use data from the Demographic and Health Surveys in four African countries to estimate an adjusted relative risk of 1.28 for prevalent HIV infection in young women aged 15-24 years associated with ever-use of depo-medroxyprogesterone acetate (DMPA). Considering that 22% of young women had used DMPA they calculate that DMPA was responsible for 6% of HIV infections in young women and conclude that "[t]he small effect of DMPA in the general population is reassuring." I am not reassured. When we consider veterinary medicine we can focus on the herd. But DMPA is offered to individual women. In many communities throughout Southern and East Africa 15-30% of women aged 24 years are HIV positive. If Leclerc et al. are correct ever-use of DMPA would be responsible for HIV infections in roughly 4-8% of users (calculating that 22% of women have used DMPA and that use increases HIV prevalence by 1.28 times). Health care professionals are obligated to giveclients accurate information about risks. On the basis of Leclerc et al. analyses governments in East and Southern Africa should mandate that family planning programs warn women that DMPA use increases their risk for HIV infection. And donors should reconsider their support for DMPA in communities with generalized HIV epidemics. (To put this situation in perspective consider what European governments would do if studies showed that a health intervention killed 4-8% of women accepting the intervention.) These cautions could be reversed if and when further research shows that DMPA use is not a risk for HIV infection. It may be for example that the association that has often been observed between HIV infection and DMPA use in Africa and Asia has been due to unsafe injections delivering DMPA rather than to any biological effect of DMPA. That possibility should be investigated. A study in Tanzania identified DMPA injections as a risk for hepatitis C infections. Reuse of syringes and/or needles without sterilization has been common in Africa and parts of Asia. Unfortunately Leclerc et al. did not consider unsafe injections. If future research finds that unsafe injections are the link between HIV and DMPA use then it is an easy matter to break that link by ensuring exclusive use of prefilled syringes or single-dose vials and new disposable syringes. (full text)
The World Bank Research Observer, 2002
Many transition and developing economies have reduced direct public involvement in the production... more Many transition and developing economies have reduced direct public involvement in the production and trade of seed and other agricultural inputs. This trend creates opportunities for farmers to realize improved access to inputs, including technology from international private research. Unfortunately, input regulations often derail these opportunities by blocking private entry and the introduction of private technology. This study looks at the experience in Bangladesh, India, Turkey, and Zimbabwe to see whether regulations make a difference in agriculture and input industries in developing economies. In all countries, companies and farmers responded to regulatory reforms by introducing and adopting more new technology and by expanding the production, trade, and use of inputs. The increased use of private technology has brought higher yields and incomes, allowing farmers and consumers to reach higher levels of welfare. These results challenge governments to open their regulatory systems to allow market entry and the introduction of private technology through seeds and other inputs.
BJOG: An International Journal of Obstetrics and Gynaecology, 2003
IntroductionDuring 2004-15, nine randomized controlled trials (RCT) for HIV prevention tested pre... more IntroductionDuring 2004-15, nine randomized controlled trials (RCT) for HIV prevention tested pre-exposure prophylaxis (PrEP) with oral drugs, vaginal gels, or vaginal rings among more than 17,000 women in Africa.MethodsThis study uses information from the nine RCTs to estimate the proportions of HIV from sexual and bloodborne risks, to consider reasons for success or failure with oral PrEP, and to consider risks with vaginal PrEP.ResultsEstimating from women’s reported frequencies of unprotected coital acts in six RCTs, only a minority of women’s infections came from sex. Oral PrEP may have succeeded in at least one trial by reducing infections from both bloodborne and sexual risks. Oral PrEP may have failed in several trials, at least in part, because some women used oral PrEP when they had sexual risks rather than daily as advised. Relatively high incidence with PrEP vaginal gels and rings vs. oral placebo suggests vaginal PrEP had little impact at best and may have been harmful....
Clinical Infectious Diseases, 2009
It seeks to persuade the reader that heterosexual transmission of human immunodeficiency virus ty... more It seeks to persuade the reader that heterosexual transmission of human immunodeficiency virus type 1 (HIV-1) has been overestimated as a factor in past and continuing HIV-1 epidemics in southern Africa (as well as other regions in Africa, Asia, and the Caribbean) and that blood exposures have in turn been underestimated. It does not make for comfortable reading, and indeed it may enrage some, for this is a text that pulls few punches and does not hesitate to name the names of those the author considers responsible. Chapter 1 clearly sets out the agenda, "to motivate the public, reporters, politicians, and lawyers in those countries to do what is necessary to protect themselves and to stop HIV transmission through blood exposures" (p 5). However, it is curious that, in this introduction, the author suggests that the reader can "skip some of the more technical parts of [chapter 8] without losing the train of the argument" (p 6). It is in chapter 8 that the author reviews the estimates of the proportion of HIV-1 infections that comes from blood Clinical Infectious Diseases 2009; 49:1290-1 Permission to reprint a book review in this section may be obtained only from the reviewer.
The World Bank Economic Review, 2000
In the past few decades many developing countries have liberalized trade and investment, removing... more In the past few decades many developing countries have liberalized trade and investment, removing barriers to imports and allowing the introduction of new foreign technologies. Unfortunately, agriculture often remains outside this reform process. Regulatory obstacles continue to restrain the transfer of technologies through private trade in seeds and other inputs. Industrial countries characteristically allow the transfer of private and public technologies through multiple channels. Developing countries often force technology transfer through a single channel controlled by government agencies, with an emphasis on official performance tests. This article analyzes the institutional arrangements governing the international transfer of new agricultural technologies, examining the cases of agricultural machinery in Bangladesh and seed varieties m Turkey. The analysis shows that allowing the private transfer of technologies and refocusing input regulations on externalities could lead to significant productivity and income gains in developing countries. David Gisselquist is an independent consultant, and Jean-Marie Grether is a lecturer at the University of Geneva and the University of Neuchitel. Their e-mail addresses are dgisselquist9ivorldbank.org and grether®ibm.unige.ch@internet. The authors thank Jaime de Melo, three anonymous referees, and participants at the conference Trade and Technology Diffusion: The Evidence with Implications for Developing Countries, sponsored by the Fondazione Eni Enrico Mattel and the International Trade Division of the World Bank and held in Milan on April 18-19, 1997, for helpful comments and suggestions.
Uploads
Papers by David Gisselquist
The intended audience for this book includes teachers, reporters, clergy, local leaders, activists, lawyers and others in the general population. I hope the information here will help people who know about one or more unexplained HIV infections to mobilize community and government efforts to find and fix whatever caused the infections. Although I have not written for health professionals, I expect many will be interested in the issues discussed here and may be ready to support investigations.