Breakthroughs Blog: Vaccines

A new real-world study found that a recently approved vaccine designed to reduce deadly meningitis in Africa is safe when used at scale. Neisseria meningitidis, or meningococcus, is a bacterium that is the leading cause of bacterial meningitis, a dangerous infection, in Africa. The African meningitis belt, which encompasses 26 countries in sub-Saharan Africa, has the highest rates of meningococcal disease, facing frequent epidemics. Since 2010, the introduction of a vaccine targeting one of the 12 bacterial strains has dramatically reduced meningitis in the region. The newer vaccine targets the five subtypes that are responsible for almost all epidemic meningitis in the region, and it was shown to be safe in a study analyzing data from more than 4.8 million people vaccinated during outbreak response campaigns in Nigeria and Niger in 2024. A research team has developed a breath-based test for diagnosing bacterial infections that showed promise in early studies in mice, which could eventually offer a non-invasive, portable, and quick alternative to the current toolbox of blood tests, imaging, cultures, and molecular diagnostics that can be slow, non-specific, and expensive. The researchers were inspired by a breath test for Helicobacter pylori, which works by a patient drinking a liquid containing traceable substances metabolized by H. pylori and then exhaling into a device that measures the components of their breath, indicating if an infection is present. Aiming to develop a breath-based test for a broader range of infections, the team developed a prototype using sugar and sugar alcohols tagged with a traceable form of carbon that bacteria metabolize but is not harmful to human cells, analyzing the breath using a simple technique. A team of researchers has designed a vaccine that turns mosquitoes into delivery vehicles to immunize bats against rabies and Nipah virus. Bats host a wide range of dangerous pathogens, which are increasingly spilling over into human and livestock populations. Researchers have previously tried testing experimental vaccines on captive bats, but the vaccines haven’t worked as effectively in the wild. Culling bat populations is another way to reduce disease transmission, but this can cause disruption to the ecosystem and can inadvertently heighten virus transmission by increasing human exposure. The new method involves an experimental vaccine that is delivered via the saliva of mosquitoes, which is transferred when bats eat the mosquitoes or the mosquitoes feed on the bats, directly targeting the natural reservoirs of these viruses to prevent spillover transmission. 

Newly shared results from a Phase 3 clinical trial found that a single-dose dengue vaccine was highly effective at preventing severe dengue, as the mosquito-borne disease continues to spread into new areas around the world. The vaccine, developed by the Butantan Institute in Brazil, was recently approved in Brazil for use in people aged 12 to 49 years old. The new trial found that among thousands of participants aged 2 to 59 years old, the vaccine was effective at preventing symptomatic dengue but especially effective—80.5 percent— at preventing hospitalization for at least five years. The World Health Organization (WHO) has shared new guidance highlighting critical targets for new antibiotics, as the global threat of antimicrobial resistance (AMR) continues to grow and outpace the development of new and innovative antimicrobials. The three areas outlined are the development of new drugs to fight Gram-negative bacteria that cause serious infections that are especially difficult to fight; new drugs for patients with serious infections that can no longer be treated with vancomycin, a powerful last-resort antibiotic; and new treatments for bacterial meningitis, which is getting harder to treat due to growing antibiotic resistance. While the research and development of a new antibiotics can be difficult, expensive, and not as profitable as other products, WHO aims to highlight key areas for investors and developers to focus their efforts to grow the pipeline of new, urgently needed tools. Last week, the Sabin Vaccine Institute announced that it has completed enrollment in six Phase 2 clinical trials for its Marburg and Sudan Ebolavirus vaccines in Kenya, Uganda, and the United States, as increasing outbreaks of both viruses in recent years have highlighted the urgent need for vaccines. There are currently no licensed vaccines for protection against the highly contagious, life-threatening diseases caused by these viruses. The Marburg vaccine has also been evaluated during recent outbreaks in Rwanda in Ethiopia. Both candidates have so far demonstrated strong safety and efficacy profiles. The Sabin Vaccine Institute has also begun planning larger Phase 3 trials for each of the vaccines. 

A research team has identified a protein in the malaria parasite that could offer a promising new target for antimalarial drug development. The researchers found that the protein Aurora-related kinase 1, or ARK1, is essential for the survival and transmission of the malaria parasite. When the researchers turned it off in the lab, the parasite could no longer replicate or complete its development in either humans or mosquitoes, effectively stopping its ability to transmit disease. The ARK1 in malaria parasites is also very different from the version found in human cells, meaning drugs designed to target the protein could be effective without causing harm to humans.  A Phase 3 trial found that a novel single-tablet combination treatment regimen for HIV provided similar viral suppression compared to a multi-pill therapy in older adults, a significant step toward a simpler option for patients who cannot use currently available single-table regimens. The trial included older adults living with HIV who had sustained viral suppression and long treatment histories and remained on complex regimens because of prior drug resistance, intolerance, or other factors that made single‑tablet options unsuitable. The single-tablet regimen was not only similarly effective, but it was also associated with increased treatment satisfaction, as well as improvements in cholesterol and triglyceride levels. Last week, IAVI announcedthat a large Phase 2b trial of the tuberculosis (TB) vaccine candidate MTBVAC will expand to include a new cohort of 1,200 patients who have never been exposed to the Mycobacterium tuberculosis bacterium that causes TB disease. The additional cohort will enable researchers to gather robust safety and immunological data across patients with and without confirmed previous TB infection, increasing understanding of how the vaccine works across diverse populations. MTBVAC is a single-shot vaccine designed to be accessible in remote and low-resource settings; it’s also the only live-attenuated candidate derived from M. tuberculosis currently in trials.

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.