ASTMH Annual Meeting 2022blog
Expanding use of and learning from the first malaria vaccine, RTS, S-AS01
By: Scott Gordon, Phd, Path and Mary J. Hamel, M.d., Who
In October 2021, the World Health Organization (WHO) recommended widespread use of the RTS,S/AS01 (RTS,S) malaria vaccine among children living in regions with moderate to high P. falciparum malaria transmission, as defined by WHO. Recent milestones for the first malaria vaccine will ensure that many more children will benefit from the vaccine’s life-saving impact. These milestones include WHO prequalification of RTS,S; UNICEF’s agreement with the manufacturer, GSK, to supply 18 million doses of the vaccine over the next three years; the opening of Gavi, the Vaccine Alliance’s funding opportunity for countries to roll out the vaccine; and completion of the Framework for the allocation of limited malaria vaccine supply that will prioritize initial limited supply to children at highest risk of malaria illness and death.
New communities in pilot areas of Ghana, Kenya and Malawi are expected to have access to the vaccine through each of the countries’ routine immunization programmes within the next few months.
More than 24 countries in Africa have expressed interest in adopting the malaria vaccine as part of their national malaria control strategies.
In this session “Symposium 43: Scaling up the world’s first malaria vaccine recommended for use” at TropMed22, co-chaired by Scott Gordon of PATH and Mary Hamel of WHO, speakers from the Liverpool School of Tropical Medicine, GSK, WHO, Kenya’s Ministry of Health, and PATH presented lessons learned from the pilot implementation of the malaria vaccine in three African countries, how to allocate the currently limited malaria vaccine supply to countries in a fair and transparent way, cost effectiveness, as well as global efforts to increase supply as rapidly as possible to maximize the vaccine’s impact.
The presenters highlighted high community and health worker acceptance of the malaria vaccine with high coverage of the primary dose series, achieved and sustained through the COVID-19 pandemic, as well as the cost effectiveness of the vaccine, based on modeling. High uptake has been facilitated by strong collaboration between the national malaria and immunisation programmes. However, comparatively low coverage of the 4th dose emphasizes the current challenge of low uptake of child health interventions in the second year of life and calls for innovative strategies to integrate and optimize delivery of essential health interventions, including vaccinations, across the life course.
Key operational considerations, learned from RTS,S research and introduction, were highlighted and will be useful as next malaria vaccines move through clinical development. These considerations include the desirability of flexibility in vaccination schedules to facilitate strategies to increase uptake; the observation that vaccine efficacy can be enhanced by providing vaccination prior to peak transmission seasons in areas of highly seasonal malaria; the understanding that vaccine efficacy can vary by transmission setting or intensity; and the opportunity to increase impact by combining malaria vaccination with other malaria prevention interventions. These lessons are being compiled by the ministries of health in Ghana, Kenya and Malawi, WHO and PATH, even as the pilots continue through 2023 to evaluate the vaccine’s impact on child mortality and the added benefit of the 4th dose. They will inform plans to deploy the vaccine in additional countries, which is expected as early as late 2023.
Anticipating the gap between high demand for the vaccine and available supply in the next few years, WHO supported the development of the framework to guide how limited supply will be allocated across malaria-endemic countries. The framework, which was discussed during the symposium, provides principles and values for allocation and prioritizes children living at highest risk from severe malaria and death to receive the vaccine first. Because of this, all countries will need to consider a phased vaccine introduction, with expansion to other areas as supply increases in the coming years.
The malaria vaccine is providing added protection against malaria to over 1 million children, thanks to the commitment and support of a wide range of partners. Continued efforts will be critical to reach the millions more children living at risk of malaria illness and death – to contribute to longer, healthier lives for all.
Scott is the Director of the Malaria Vaccine Implementation Programme for PATH
Mary is Senior Technical Officer and Team Lead for Malaria Vaccines at the World Health Organization