1. Impact of Chemoprophylaxis on Plasmodium vivax and Plasmodium ovale Infection Among Civilian Travelers: A Nested Case-Control Study With a Counterfactual Approach on 862 Patients.
- Author
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Le Goff M, Kendjo E, Thellier M, Piarroux R, Boelle PY, and Jauréguiberry S
- Subjects
- Humans, Atovaquone therapeutic use, Plasmodium vivax, Case-Control Studies, Travel, Chloroquine therapeutic use, Chemoprevention, Antimalarials therapeutic use, Plasmodium ovale, Malaria drug therapy, Malaria, Vivax drug therapy, Malaria, Vivax prevention & control
- Abstract
Background: The impact of chemoprophylaxis targeting Plasmodium falciparum on Plasmodium vivax and Plasmodium ovale, which may remain quiescent as hypnozoites in the liver, is debated., Methods: We conducted a nested case-control analysis of the outcomes of P. vivax and P. ovale infections in imported malaria cases in France among civilian travelers from 1 January 2006, to 31 December 2017. Using adjusted logistic regression, we assessed the effect of chemoprophylaxis on the incubation period, time from symptoms to diagnosis, management, blood results, symptoms, and hospitalization duration. We analyzed the effect of blood-stage drugs (doxycycline, mefloquine, chloroquine, chloroquine-proguanil) or atovaquone-proguanil on the incubation period. We used a counterfactual approach to ascertain the causal effect of chemoprophylaxis on postinfection characteristics., Results: Among 247 P. vivax- and 615 P. ovale-infected travelers, 30% and 47%, respectively, used chemoprophylaxis, and 7 (3%) and 8 (1%) were severe cases. Chemoprophylaxis users had a greater risk of presenting symptoms >2 months after returning for both species (P. vivax odds ratio [OR], 2.91 [95% confidence interval {CI}, 1.22-6.95], P = .02; P. ovale OR, 2.28 [95% CI, 1.47-3.53], P < .001). Using drugs only acting on the blood stage was associated with delayed symptom onset after 60 days, while using atovaquone-proguanil was not., Conclusions: Civilian travelers infected with P. vivax or P. ovale reporting chemoprophylaxis use, especially of blood-stage agents, had a greater risk of delayed onset of illness. The impact of chemoprophylaxis on the outcomes of infection with relapse-causing species calls for new chemoprophylaxis acting against erythrocytic and liver stages., Competing Interests: Potential conflicts of interest. M. L. G. reports support for attending meetings and/or travel from the European Congress of Clinical Microbiology and Infectious Diseases. M. T. reports payment or honoraria as a speaker at the Colloque Experts Praticiens Infectiologie on 4 February 2022 in Paris for Pfizer. S. J. reports payment or honoraria for lectures, presentations, speaker’s bureaus, manuscript writing, or educational events from Alfa Sigma expert board; participation on a data and safety monitoring board or advisory board for Artesunate; and data safety surveillance on behalf of the French National Agency for the Safety of Medicines and Health Products. All other authors report no conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2023
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