#71 – Saloni Dattani on Malaria Vaccines and Missing Data in Global Health
Oct 19, 2023
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Saloni Dattani, a researcher at Our World in Data and founder of Works in Progress, discusses the history of malaria eradication efforts, delays in developing a malaria vaccine, the rollout of the RTS,S vaccine, the issue of missing global health data, and the uncounted deaths from snakebites in India. They also talk about new funding models for life-saving research like vaccines for TB and HIV.
The development of a malaria vaccine faced challenges including funding, optimizing effectiveness, and long-term efficacy.
Increased funding and collaboration were crucial for advancing malaria vaccine research.
Lessons learned from COVID-19 include the importance of streamlining clinical trial processes and enabling multiple trials to run simultaneously.
Limited funding for diseases like malaria, tuberculosis, and HIV hinders vaccine development in low-income countries.
Innovative approaches like gene drives and bacterial prevention show promise in the fight against malaria.
Deep dives
Discovery of the CSP protein and vaccine development
In the mid-1980s, researchers discovered the circumsporozoite protein (CSP) on the surface of the malaria parasite and identified it as a potential target for a vaccine. They partnered with GSK to develop a vaccine using a combination of CSP proteins and adjuvants. The vaccine, known as RTSS, went through years of trial and error to optimize its effectiveness and scalability. Field trials in the Gambia showed promising results, with an efficacy rate of 30%. However, concerns were raised about the long-term efficacy of the vaccine. Funding for further research and clinical trials was challenging to secure, but initiatives like the Malaria Vaccine Initiative and the Gates Foundation provided support in the mid-2000s.
Challenges in Malaria Vaccine Development
Developing a vaccine for malaria was challenging due to the complex nature of the parasite and the multiple stages of its life cycle. Parasites, unlike viruses, are more difficult to target with vaccines as they undergo various transformations. The discovery of the CSP protein and its adjuvanted formulations offered promise, but optimizing the immune response and ensuring long-term efficacy presented challenges. Funding for research and clinical trials was not always readily available, and competing priorities in malaria control, such as insecticides and bed nets, further limited resources dedicated to vaccine development.
Funding and Continued Research Efforts
Despite initial hurdles, funding for malaria vaccine research increased in the mid-2000s, thanks to initiatives like the US President's initiative and the Gates Foundation. These funds supported further clinical trials and ongoing research. The focus was not only on vaccine development but also on insecticides, bed nets, and other malaria control measures. Researchers continued to refine and optimize the RTS vaccine, seeking to improve its effectiveness and address concerns about long-term protection. The collaboration between research institutions and organizations like GSK, along with increased funding, played a crucial role in moving malaria vaccine development forward.
The Future of Malaria Vaccine Development
The development of a malaria vaccine continues to be a challenging endeavor. While the RTS vaccine has shown promise, ongoing research aims to improve its effectiveness and address concerns about waning efficacy over time. Scientists are exploring new vaccine targets and strategies, considering the complex nature of the parasite's life cycle. Funding and collaboration between public and private sector entities remain key to advancing malaria vaccine research. Despite the challenges, progress in vaccine development offers hope in the fight against malaria, a disease that disproportionately affects populations in the global South.
Long Road to Vaccine Approval
The process of developing and approving a vaccine can be lengthy, as seen in the case of the malaria vaccine, which took over 20 years to gain approval. Factors contributing to the delay included limited funding, the difficulty of conducting clinical trials in Africa, and safety concerns. Regulatory processes, such as the World Health Organization's approval, also played a role. In contrast, the development of COVID-19 vaccines was expedited due to the global emergency and the availability of substantial funding. Lessons learned from COVID-19 include the importance of streamlining clinical trial processes and enabling multiple trials to run simultaneously.
The Global Health Funding Challenge
The development of vaccines for diseases like malaria, tuberculosis, and HIV faces challenges due to limited funding. These diseases predominantly affect low-income countries, where healthcare spending is significantly lower than in wealthier nations. Philanthropic initiatives, such as advanced market commitments, have been successful in incentivizing vaccine development and manufacturing. However, the cost-effectiveness of funding vaccine research varies depending on the complexity of the disease and the potential return on investment. Continued efforts are needed to address funding gaps and support research for neglected tropical diseases.
Gene Drive and Other Approaches
In the fight against malaria, innovative approaches like gene drives have been explored. Gene drives involve genetically engineering mosquitoes to carry traits that could reduce the spread of malaria, such as infertility in female mosquitoes or resistance to the disease. However, the use of gene drives raises ethical and regulatory concerns, and more research is needed to assess their safety and effectiveness. Other strategies, like harnessing bacteria to prevent mosquito-borne diseases, have shown promise in reducing the burden of diseases like dengue. Collaborative efforts, international regulations, and adequate funding are crucial for advancing these cutting-edge approaches.
Lessons from COVID-19 for Global Health
The COVID-19 pandemic has highlighted the importance of timely and standardized data collection. Robust data systems and platforms for reporting and sharing data are essential for effective response and research. Lessons from COVID-19 include the need for routine data collection on emerging diseases, the role of international organizations in setting data standards, and the value of flexibility in clinical trial processes. Strengthening global health infrastructure and capacity can contribute to faster vaccine development and response to future public health crises.
Underreported Deaths and Causes
Many deaths worldwide are not registered, and among the registered deaths, a significant number lack a cause of death on the certificate. This lack of registration and cause reporting is particularly glaring in South Asia and Africa. The reasons for these gaps include a lack of healthcare professionals who know how to list a cause of death, limited access to medical records, and the challenges in determining the exact cause of death. For example, snakebite-related deaths are often uncounted because they predominantly occur in rural areas with limited healthcare access. Improving death registration and cause reporting is crucial for accurate data on mortality rates.
Verbal Autopsy and Estimating Global Burden
To address missing cause of death data, verbal autopsies are used in some regions. Verbal autopsies involve interviewing individuals who knew the deceased to gather information on symptoms and conditions leading up to their death. While this method has limitations, it has provided valuable insights. For instance, a large verbal autopsy study in India revealed that snakebite-related deaths were significantly underestimated. This prompted efforts to develop better anti-venom and improve access to healthcare in rural areas. Additionally, verbal autopsies have shed light on the burden of mental illness, which is often underreported due to cultural and societal factors. Collecting and utilizing accurate cause of death data through innovative methods is essential for effective policymaking and resource allocation in global health.
What comes after vaccine discovery — rolling out the RTS,S vaccine
New funding models to accelerate similar life-saving research, like vaccines for TB and HIV
Why so much global health data is missing, and why that matters
How the ‘million deaths study’ revealed that about 50,000 deaths per year from snakebites in India went uncounted by health agencies
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