Breakthroughs Blog: Vaccines

An international research team, led by scientists at the University of Maryland School of Medicine, shared the results of the Phase 1 trial of a novel vaccine designed to protect against typhoid fever and non-typhoidal Salmonella infections, reporting that the vaccine produced a strong immune response and was safe and well-tolerated in a small group of healthy US adults. These encouraging findings pave the way for the next step of evaluating the vaccine in children. A single vaccine that targets Typhoid fever and non-typhoid Salmonella, both leading causes of illness and death in children in Africa, could be a game-changer for pediatric health. The vaccine could also help protect people in the United States and other high-income countries, where some types of Salmonella are common causes of foodborne illness. Following the example of the US military, who often wear uniforms treated with insecticide to repel mosquitoes in malaria-endemic regions, a research team has tested a similar approach to try to protect young children, who face a significant burden of malaria in sub-Saharan Africa. While existing vector control tools, such as insecticide-treated bednets, only protect children while they’re sleeping, a large randomized controlled trial in Uganda tested the efficacy of insecticide-treated baby wraps, used in conjunction with bednets. The trial found that the baby wraps were highly effective at preventing malaria infections. The dramatic scale of the reduction of new infections also suggests that malaria-carrying mosquitoes were biting during the daytime more often than previously thought, which could help guide the development of new vector control tools and approaches. Last week, The Safety of Antimalarials in the FIRst trimEster (SAFIRE) consortium announced that it had enrolled its first patient in Mali, marking the official start of the first-ever Phase 3 adaptive platform trial evaluating the efficacy and safety of antimalarial drugs in the first trimester of pregnancy. The trial is a landmark achievement that could not only help fill the crucial gap of safe and effective options for pregnant women at risk of malaria, but it is also a step toward equity and inclusion for clinical research and drug development in general, which have long excluded pregnant women, fueling the gap in the first place. SAFIRE partners have shared that early formative research in the communities where the trial will take place was a crucial step in ensuring that the design and process were appropriate and acceptable to the communities. The study will continue to progress in Mali, Burkina Faso, and Kenya. 

Last week, the World Health Organization (WHO) published its latest reports on the new antibacterial agents and diagnostics in the pipeline, seeking to encourage research and development (R&D) to invigorate the sparse pipeline of tools to address the growing global threat of antibiotic resistance. The report highlights a lack of innovation in the antibacterial pipeline and major gaps in antibacterials targeting the most critical bacterial threats and addressing needs like pediatric formulations and oral treatments for outpatient use. There are similar persistent gaps for diagnostics, including a lack of new tests that are affordable, robust, and easy to use in low-resource settings. A new study, led by Imperial College London and supported by the Coalition for Epidemic Preparedness Innovations (CEPI) found that vaccines designed to protect against a wide range of coronaviruses, including a novel sarbecovirus, the type of coronavirus that includes the viruses that caused SARS and COVID-19, could be a gamechanger in a future global coronavirus pandemic, dramatically reducing deaths and disruption. A broad vaccine like this could be manufactured and stockpiled before an outbreak arises and quickly rolled out when a new outbreak is identified, providing protection to high-risk populations 60 years and older. This immediate protection could be a powerful stopgap while a new vaccine targeting the specific virus behind the outbreak is developed. An international research team has developed a simple, affordable HPV test that delivers results in less than an hour outside of a specialized laboratory, which could be a breakthrough for improving access to cervical cancer screening for women in low-resource settings. Cervical cancer continues to cause more than 350,000 deaths every year, particularly in low- and middle-income countries with limited regular access to cervical cancer screening. The test uses a swab sample and a battery-operated portable device, projected to cost less than $8 each, and it was found to be highly accurate compared to the reference standard. 

A Phase 1 clinical trial testing an experimental monoclonal antibody for malaria found that the highest dose of the treatment studied was highly effective in preventing malaria. Researchers from the University of Maryland, Sanaria, the Vital Narrative consultancy, and the Gates Medical Research Institute tested the monoclonal antibody, MAM01, in 37 adults who had never been exposed to malaria, who received either a single dose of varying sizes or a placebo, and then were infected by the bites of infected mosquitoes. None of the three recipients who received the highest dose had malaria parasites in their blood after infection. The monoclonal antibody could prove to be an important treatment option that provides immediate, high-level, and long-lasting protection with just one doseA Japanese research team has isolated natural compounds from marine sponges that demonstrate an ability to kill parasites that cause leishmaniasis, which affects approximately 12 million people around the world. Current treatments are highly toxic, cause serious side effects, and can be prohibitively expensive, leaving patients, particularly in low-income communities, which face a disproportionate burden of leishmaniasis, unable to access or complete treatment. Drug resistance is also complicating leishmaniasis treatment efforts. These findings could guide research into new treatment approaches and could potentially also be applied to other protozoan diseases like Chagas disease and African sleeping sickness. A new CRISPR-based RNA test could help track the parasites that spread Human African trypanosomiasis, or sleeping sickness, which affects around 500 people per year and many more livestock animals. The test can identify parasite species living in an animal’s blood, helping public health workers carry out targeted treatment of infected animals and prevent transmission to humans. This One Health approach to zoonotic or parasitic diseases could also be rolled out to address other diseases, such as Chagas disease or leishmaniasis.  

This month marks 35 years since the World Summit for Children, the first time in history when a meeting of heads of state and government was held exclusively to address the well-being of children. At this landmark event in New York City, world leaders adopted a Declaration on the Survival, Protection, and Development of Children and a Plan of Action for its implementation, which made specific recommendations in a variety of areas, including child and maternal health and family planning. We’ve made significant progress in children’s health globally since then—the total number of deaths of children under five worldwide has declined from 12.8 million in 1990 to 4.8 million in 2023. The number of neonatal deaths (deaths in the first 28 days) has also dropped, although more slowly, from 5.2 million in 1990 to 2.3 million in 2023. However, there are still major challenges in children’s health, especially in the Africa region, where children continue to have the highest risk of dying before reaching age five. Infectious diseases, including acute respiratory infections, diarrhea, and malaria, as well as birth complications, remain among the leading causes of death for children under five. More than half of child deaths are due to conditions that could be prevented and treated with adequate access to health care or other quality of life improvements, particularly in that crucial first month: neonatal deaths make up 47 percent of under-five child deaths.Another challenge is the lack of medicines designed specifically for children—only 30 percent of essential medicines are available in child-appropriate formulations. Instead, children are often treated with imprecise partial doses of medicines that were designed and tested in adults, which can lead to toxicity and complications. This gap results from a variety of barriers: it can take up to 25 years to bring a pediatric medicine to market and only one in ten clinical trials registered between 2000 and 2023 included children. Innovative technologies rolled out since 1990 have already saved millions of lives, and new tools in the pipeline designed with the needs of children, and particularly the most vulnerable kids, in mind could bring down child mortality even more. Diarrheal disease vaccines While diarrheal-disease related deaths among children under five have decreased drastically since 1990, down an estimated 79 percent from 1990 to 2021, they still cause a severe burden; 4.8 million children under five died in 2023. Rotavirus, Shigella, and enterotoxigenic Escherichia coli (ETEC) are among the common pathogens that can lead to diarrheal disease.  The first rotavirus vaccines of the generation still in use today become available just under 20 years ago, approved in the United States in 2006 and later recommended by the World Health Organization for all children. Today, these vaccines are used in more than 110 countries around the world and have contributed to a significant drop in child hospitalizations and deaths from diarrhea. Rotavirus vaccines have had a marked impact on child mortality, preventing 139,000 deaths in children under five between 2006 and 2019. However, rotaviruses are still the leading cause of severe diarrhea in children under five in low- and middle-income countries, pointing to the need for increased access to existing vaccines, as well as new and more effective ones.Unfortunately, approved vaccines don’t yet exist for ETEC and Shigella, though promising candidates are in development. PATH is working with partners to advance vaccines against these bacteria, which could help save thousands of additional lives. For Shigella, PATH is working with the US Naval Medical Research Command and the Walter Reed Army Institute of Research to advance a vaccine candidate, which demonstrated strong safety and efficacy in a recent Phase 1 trial. PATH is also working with these US partners, alongside Sanofi Pasteur and the Infectious Disease Research Institute, to advance an ETEC vaccine candidate, which displayed strong potential in a Phase 1 trial in adults, paving the way for the development of a vaccine for infants and young children, who face the highest risk. If they continue to prove successful, these vaccines could have a tremendous public health impact, not only preventing deaths but also reducing the long-term health and economic effects of malnutrition and developmental delays associated with experiencing severe diarrhea, as well as limiting the growth of antimicrobial resistance.  Pediatric products for malaria and more Children under five account for nearly 80 percent of global malaria deaths. Despite this significant burden, for a long time, there was a lack of a suitable malaria medicines for children, who were treated with crushed tablets designed for adults. The first child-friendly, quality-approved malaria treatment, launched in 2009 by Medicines for Malaria Venture (MMV) and Novartis, is sweet-tasting and quickly dissolves in water. 500 million courses of Coartem® Dispersible have been delivered worldwide as of this April, saving more than 1.8 million lives. MMV also delivered the first malaria treatment for newborn babies and young infants, which is an adapted version of Coartem® that was approved earlier this year. The two first-ever malaria vaccines, approved in the last five years, have been another major game changer for children with malaria, with 21 countries in Africa having introduced them so far, alongside other complementary prevention methods like chemoprevention and vector controlMMV is also working with partner Eyam Health to develop next-generation monoclonal antibody-based approaches to create affordable, long-acting malaria preventative therapies and treatments. Eyam’s technology has the potential to deliver future durable therapies without the need for cold storage and at an extremely low cost, projecting that a single long-acting therapeutic injection could provide protection for more than 50 million children and pregnant women for the months-long rainy season, which is peak time for malaria transmission. This would significantly simplify seasonal malaria chemoprevention, which today involves taking a course of oral drugs monthly for up to five months. Alongside these innovations for malaria, child-friendly medicines for HIV and neglected tropical diseases are also helping address the gap of suitable medicines for children and reduce the burden of treatment for children and their caregivers.  Diagnostics for pre- and postnatal complications and infections Premature birth, birth complications, and neonatal infections are among the leading causes of neonatal deaths, often resulting from limited access to timely screening, particularly in low-resource settings that face a lack of health care services, poor laboratory infrastructure and insufficiently skilled health care workers. Low-cost, easy-to-use diagnostics that can be deployed at the point of care are helping ensure that mothers and babies everywhere have access to routine screening in the pre- and postnatal periods, helping catch and address complications and infections earlier. One innovation is a portable, user-friendly ultrasound developed by Philips that connects to a mobile app on a phone or tablet, helping bring high-quality diagnostics to the point of care. The technology is being rolled out in low- and middle-income countries with the support of the Gates Foundation and has already demonstrated its ability to improve informed decision-making when triaging pregnant women in rural underserved communities.Bacterial infections caused by pneumonia, sepsis, and meningitis are the primary cause of neonatal infections, and most could be averted with adequate access to preventive interventions, early diagnosis, and care. Almost half of sepsis cases occur in children under five. The Combating Antibiotic-Resistant Bacteria Biopharmaceutical Accelerator has awarded funding to Melio, AstraDx, and QuantaMatrix to demonstrate feasibility of their rapid diagnostics for neonatal sepsis, all of which aim to provide results in mere hours, down from days. Early diagnosis is particularly important because the risk of death from neonatal sepsis increases about 7.6 percent every hour treatment is delayed. These innovations have the potential to help greatly reduce the risk of babies and mothers dying from complications and infections during the critical periods before and after birth.  Thirty-five years since the World Summit for Children, we’ve made tremendous progress in children’s health. Investing in innovative technologies specifically designed for children and striving to ensure children and their needs are considered and included in research across health areas will set up future generations for an even healthier future.