Breakthroughs Blog: Vaccines

A Phase 2 trial in The Gambia found that a vaccine for enterotoxigenic Escherichia coli (ETEC), a leading cause of diarrheal disease in children in low-income countries, was safe and effective in children between 6 and 18 months old. Cases of ETEC are expected to increase in the coming years due to climate change, and the vaccine under study, ETVAX, the most advanced of the several ETEC vaccines in the pipeline, could help reduce illness and death, lower health care costs, and curb the growing threat of antimicrobial resistance. The vaccine will now advance to a large multicountry Phase 3 trial for further evaluation. A research team at the University of Buffalo has developed an inhalable drug-delivery system for treating tuberculosis (TB), which could reduce the frequency of dosing and lessen side effects. Standard treatment for TB can be lengthy and require multiple drugs, with unpleasant side effects, leading some patients to stop treatment— contributing to the emergence of drug-resistant TB. The new approach involves an inhalable nanoparticle system that modulates the immune system and carries rifampin, a common TB drug, directly to the lungs, where TB bacteria primarily reside. This targeted method contrasts with the pill formulation of rifampin, which, when taken orally, only delivers limited amounts of the drugs to lung tissue. Further studies will explore whether the nanoparticle system can deliver combination treatments, which are the cornerstone of TB treatment, and whether the system can be adapted to address other lung diseases. Ghana recently became the first-ever country to approve a new single-dose combination treatment for soil-transmitted helminths, which cause parasitic infections that affect millions in endemic regions in Africa. The regimen is as safe as the standard drug used in mass deworming campaigns and demonstrates improved efficacy against whipworms, which are often resistant to the single-drug treatment. The medicine is also fruit-flavored, fast-dissolving, and incorporates a novel age-based dosing strategy, making it suitable for children. Administering the two drugs incorporated in the combination treatment previously required between two and six pills per person. 

A new study has found that five human cases of a mysterious, bat-borne virus in Bangladesh, initially thought to be Nipah virus, were actually caused by another emerging bat-borne virus called Pteropine orthoreovirus (PRV). Between late 2022 and early 2023, five patients were admitted to hospitals with severe symptoms, all of whom had consumed raw date palm sap, which is also consumed by bats. Health care workers thought they had the Nipah virus, for which bats are a known vector, but they all tested negative. Several of the patients continued to experience severe symptoms after being discharged, and one ultimately died the following year. Human PRV cases have been reported other countries, but typically resulted in much milder respiratory illness, suggesting that the virus may have undergone genetic changes, making it more transmissible and virulent. These findings underscore the need for robust, vigilant surveillance of emerging diseases, particularly bat-borne pathogens. Last week, the Population Council announced that it has executed a global, exclusive license agreement for the Nestorone®/Testosterone (NES/T) male contraceptive gel, transferring the program to Contraline Inc., which will lead late-stage development toward potential global regulatory approvals as the first reversible contraceptive drug for men. The product, if approved, could transform contraception, enabling men to take on a responsibility that has historically fallen on women. NES/T is the most advanced investigational male contraceptive in the pipeline, and the Phase 3 clinical trial being planned is expected to be the first-ever Phase 3 trial of a hormonal male contraceptive. It is a daily topical gel that suppresses sperm production while maintaining normal testosterone levels, which was co-developed by the Population Council and the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health.  An early-stage trial evaluating a nasal spray vaccine for H5N1 bird flu found that the vaccine generated a strong immune response in rodents, a significant first step toward a vaccine capable of slowing the spread of bird flu, which in recent years has continued its worrying global spread among animal populations, with occasional human cases. While traditional injected flu vaccines are highly effective at preventing serious illness, they are less effective at reducing infection in the first place. Nasal vaccines, which work at the place of infection, can more effectively stop infections and prevent onward transmission to others. They are also believed be more effective against rapidly mutating viruses because they train the immune system differently than traditional vaccines, stimulating mucosal immunity in the nose and upper airway, and can respond to features of the virus that are shared across different strains, meaning they can remain effective for longer without needing updating. There are H5N1 vaccines stockpiled in several countries, but most of these were developed to target previously circulating strains of the virus and are poorly matched to the newer, rapidly mutating strains we have seen in recent years. 

Women are steadily reshaping the landscape of global health research. In 2022, they made up 41 percent of researchers worldwide, representing considerable progress toward closing the gender gap in science. Yet women remain underrepresented in many scientific fields and in senior roles, are published and cited less frequently than men, and file far fewer patent applications. Despite these systemic barriers, women researchers are having an outsized impact on global policy and progress. Research led by women is more likely to address topics aligned with the Sustainable Development Goals, and publications with women authors are more frequently cited in policy documents.  Expanding women’s participation and leadership in science is not just a matter of equity, it is essential to ensuring research priorities reflect women’s lived experiences. Although women spend more of their lives in poor health than men, only 1 percent of global health research and development funding targets female-specific conditions beyond cancer. Even as gaps persist, women scientists are already at the forefront of innovation, driving cutting-edge technologies that could transform the future of global health. Advancing promising HIV vaccine strategies Developing an HIV vaccine capable of preventing infection has long challenged researchers due to the virus’s extraordinary ability to mutate and evade the immune system. Still, many experts believe such a vaccine will be essential to ending the global pandemic.A Phase 1 trial, launched in August of last year, is evaluating an investigational HIV vaccine candidate designed to induce an immune response scientists believe could effectively target vulnerable parts of HIV-infected cells. Three distinguished female principal investigators—Dr. Tariro Makadzange of the Mutala Trust, Dr. Theodorah Rirhandzu Ndzhukule of the Desmond Tutu Health Foundation, and Dr. Limakatso Lebina of the Africa Health Research Institute—are overseeing the study across clinical trial sites in Harare, Zimbabwe; Cape Town, South Africa; and Durban, South Africa, respectively.  Another Phase 1 trial, launched just last month, is testing a different novel approach. Researchers are evaluating whether highly specialized vaccine immunogens, delivered in a specific sequence, can train the immune system to produce broadly neutralizing antibodies against HIV, widely considered one of the keys to achieving broad protection against the virus. The trial is led by Dr. Linda-Gail Bekker, CEO of the Desmond Tutu Health Foundation and a leading HIV clinician-scientist. These vaccines have the potential to transform the lives of women and girls, who bear a disproportionate burden of HIV and AIDS, particularly in sub-Saharan Africa. The leadership of these scientists underscores how women researchers are driving forward breakthroughs that address urgent global health needs. Trialing promising TB vaccine candidates New tuberculosis (TB) vaccine candidates also hold promise for reshaping global TB efforts, particularly as rising drug resistance makes the disease harder to fight. The only currently approved TB vaccine is more than 100 years old and is effective at preventing some forms of TB in infants but offers limited protection against pulmonary TB in adults.  One next-generation vaccine candidate, MTBVAC, was co-designed by Dr. Brigitte Gicquel of the Institut Pasteur, who is a pioneer in TB research. MTBVAC is the only live-attenuated candidate in the pipeline, meaning it contains a weakened form of the bacteria that causes TB, and aims to offer more effective, longer-lasting protection for newborns while also preventing TB disease in adolescents and adults, for whom no effective vaccine exists.In a Phase 1a/2b trial published last year, MTBVAC was found to be safe and capable of generating immune responses comparable to or stronger than the current TB vaccine. The study was led by Dr. Angelique Luabeya of the South African Tuberculosis Vaccine Initiative, who has considerable experience leading novel TB and COVID-19 vaccine trials. MTBVAC is now being evaluated in a Phase 2 trial in people living with HIV, co-chaired by the aforementioned Dr. Limakatso Lebina. Another leading vaccine candidate, M72/AS01E, is currently undergoing a large Phase 3 trial to determine whether it can protect adolescents and adults from pulmonary TB. Dr. Lee Fairlie of Wits RHI at the University of the Witwatersrand, an infectious disease expert with extensive experience leading major clinical studies, is serving as national principal investigator for the trial in South Africa. These vaccine candidates could dramatically alter the trajectory of the global TB epidemic, reflecting the critical contributions of women researchers in advancing solutions to one of the world’s oldest and deadliest infectious diseases. Driving forward antimalarial drugs for a long-excluded group Last fall, a global consortium launched the first-ever Phase 2 adaptive platform trial evaluating the efficacy and safety of antimalarial drugs during the first trimester of pregnancy. This landmark study addresses a long-standing gap in safe and effective evidence-based treatment options for pregnant women at risk of malaria. Pregnant women, particularly those in early pregnancy, have historically been excluded from clinical trials, leaving major unanswered questions about how best to treat malaria and other conditions in this high-risk group.  Among the study’s co-principal investigators are Dr. Myriam El Gaaloul from the Medicines for Malaria Venture, Dr. Stephanie Dellicour from the Liverpool School of Tropical Medicine, and Dr. Hellen Barsosio of the Centre for Global Health Research at the Kenya Medical Research Institute, who bring deep expertise in clinical trials, malaria, and maternal and newborn health. This trial has the potential to not only reshape care for pregnant women at risk of malaria but also set a powerful precedent for more inclusive research. It illustrates how greater gender diversity in research leadership can help ensure studies prioritize and better reflect the needs of the people they aim to serve. Across the global health innovation pipeline, women scientists are driving transformative progress. Accelerating gender diversity across research teams, investing in early-career women researchers, and strengthening pathways to leadership will advance gender equity while ensuring that scientific breakthroughs are more inclusive, accessible, and reflective of the needs of all people. 

Sino Biological, Inc. recently announced an effort to accelerate the development of critical research tools to support the global scientific community in advancing Nipah virus research, as new cases of the deadly pathogen have raised international concerns. Sino Biological has launched a series of proteins, which researchers can use in the lab to better understand how the virus infects cells and how to design antibodies that might successfully target the virus. These proteins are based on the currently circulating Nipah virus strains, so could help boost the accuracy and relevance of research efforts. There are currently no approved vaccines or specific antiviral treatments for Nipah, underscoring the importance and urgency of research and development efforts to advance vaccines and therapies. Newly shared results from the first blinded, randomized non-inferiority trial comparing one versus two doses of HPV vaccine show that a single dose provided similar protection to the two-dose schedule. These results verify a previous study, which undergirded the World Health Organization’s 2022 recommendation of the lower-dose regimen, which has since led to its adoption by almost 90 countries. The lower-dose regimen can help boost access and uptake of the HPV vaccine by reducing the cost and complexity of vaccination for public vaccine procurers, health care providers, and patients. Specifically, the researchers found that a single dose was 97 percent effective against HPV infections in a large study with 20,000 participants, who were studied for up to five years post-vaccination. Last week, the Drugs for Neglected Diseases initiative (DNDi) announced a new memorandum of understanding with the African Population and Health Research Center aimed at helping translate African-led research into transformative innovations and health policies. Specifically, the agreement involves coordination to promote joint research, advance evidence-based programming and policymaking, and facilitate capacity-building. The memorandum also outlines collaborative commitments to ethical, value-enhancing data-sharing activities, including generating high-quality evidence and creating a robust system to preserve and share findings.