Malaria, caused by protozoan parasites of the Plasmodium genus and transmitted by anopheline mosquitoes, remains entrenched across sub-Saharan Africa where > 95% of the global burden is borne. In 2021, there were an estimated 247 million malaria cases and 619,000 malaria-related deaths. Comprehensive malaria programs include both malaria eradication and measures to reduce morbidity and mortality. In contrast to every other inhabited continent, no sub-Saharan African nation has successfully eliminated malaria. Since 2015, malaria has resurged in some parts of the subcontinent despite unprecedented investments in malaria control over the first 2 decades of the millennium, and the recent incursion of the species Anopheles stephensi, an efficient malaria vector in urban settings, into the Horn of Africa threatens to further destabilize malaria control efforts.
The concept of a “chemical vaccine” for malaria has been proposed as an important addition to the antimalarial armamentarium in the current era of arrested progress. The concept, which refers to long-acting pharmaceuticals for prevention, is especially timely: in its latest revision, WHO guidelines greatly expand the potential applications of pharmacologic-based control measures. Perennial malaria chemoprevention, intermittent preventative treatment of malaria in school-age children, post-discharge malaria chemoprevention after hospitalization, and seasonal malaria chemoprevention are recommended as prevention strategies to decrease malaria burden and malaria-associated adverse outcomes for children living in areas of moderate to high malaria transmission.6 In adults, the WHO recommends antimalarials for the intermittent preventive treatment of malaria during pregnancy and, in a narrow range of circumstances, for mass drug administration.
Long-acting formulations of medications are available for the treatment or prevention of several conditions, including mental health, contraception, and HIV prevention. Specific to prevention strategies, long-acting formulations result in higher rates of prevention compared with oral options, potentially related to user preference and convenience leading to higher rates of medication adherence. The relative ease of production and distribution along with the strain-transcendence of long-acting formulations of antimalarial drugs, vis-à-vis the RTS,S/AS01 and R21 vaccines, contributes to their potential attractiveness for malaria chemoprevention. The most recent update to the WHO guidelines for malaria includes greater provision and latitude than any prior edition for national control programs to deploy chemotherapeutics for control and elimination, and long-acting formulations may simplify implementation, reduce medication nonadherence, and extend the duration of efficacy.
The growing use of long-acting medications has identified important patient preferences that influence the uptake of, and adherence to, medication products. Further, clinician and policymaker opinions will drive the inclusion of long-acting therapies into guidelines and practice. To inform long-acting formulation development and deployment, a survey was conducted of Kenyan and Zambian patient end-users, prescribers, and policymakers to evaluate the acceptance of and potential concerns about long-acting formulations of malaria chemoprevention.