Breakthroughs Blog: Vaccines

The Sabin Vaccine Institute has sent more than 640 doses of its investigational Marburg vaccine to Ethiopia, as the country continues to battle its first-ever outbreak of Marburg, a highly contagious and fatal disease for which there are currently no available vaccines or treatments. Soon after the outbreak was confirmed to be Marburg, Ethiopian authorities coordinated with Sabin and the Biomedical Advanced Research and Development Authority, which is supporting development of the vaccine candidate, to obtain access to doses for an outbreak trial. Sabin and the Ethiopian Ministry of Health have signed a clinical trial agreement under which Sabin is providing doses for a two-cohort Phase 2 open-label trial, involving health care and frontline workers, as well as direct contacts of people with confirmed infections. The vaccine is also being tested in Phase 2 clinical trials in Rwanda, the United States, Uganda, and Kenya, which will hopefully yield evidence to support its continued development and use as a tool in future outbreaks. The Oxford Vaccine Group has vaccinated the first volunteer in a first-in-human trial of its vaccine for Lassa fever, which is caused by Lassa virus, a deadly virus with significant epidemic potential. The trial, funded by CEPI, is being conducted among 31 people between 18 and 51 in Oxford, England, with a second Phase 1 trial in Ghana set to start in early 2026. The vaccine was developed by researchers at the Pandemic Sciences Institute at the University of Oxford and uses the same viral vector platform as the Oxford/AstraZeneca COVID-19 vaccine. The Lassa fever Coalition, led by the West African Health Organization, with support from CEPI and partners, is already working with vaccine developers to accelerate the development and equitable introduction of future vaccines across the West African region, which faces a significant burden of Lassa fever. A Penn State research team has developed a new rapid test that can differentiate active HIV from false positives, which could potentially accelerate the development of a vaccine for HIV. HIV vaccines in development are designed to trigger the body to produce antibodies that target key proteins on the virus’s surface. However, these proteins are also what diagnostic tests detect to confirm an infection, leading trial participants to falsely test positive for HIV, complicating diagnosis and clinical management. Researchers have to use timely and expensive multistep diagnostic procedures to distinguish between those with actual infections and these false positives. The Penn State researchers partnered with the HIV Vaccine Trials Network to test human blood samples with the new testing device, finding that it was highly effective at distinguishing between active infections and false positives and generated results in just five minutes. 

Newly published data shows that the antiviral compound mosnodenvir, developed by Johnson & Johnson, is effective at preventing dengue infection in people deliberately exposed to the virus, which affects millions around the world every year. There are no approved treatments for dengue, and available vaccines face production and efficacy issues. Despite its promise, the future development of the drug is in flux after Johnson & Johnson halted all its infectious disease work last year. Negotiations are underway to find another company to advance the drug, which, if it continues to demonstrate potential, could be used to protect large populations during epidemics, as well as to protect people traveling to endemic areas. Last week, Brazil’s regulatory agency approved the Butantan Institute’s Butantan-DV vaccine for dengue for people aged 12 to 59. The vaccine demonstrated high efficacy in clinical trials against dengue, which causes millions of cases globally, with a substantial burden faced by Brazil. The single-dose vaccine could offer faster and simpler vaccination campaigns compared to existing vaccines. Brazil signed an agreement with WuXi Biologics to deliver approximately 30 million doses of the vaccine in the second half of next year. The results of a human-challenge Phase 2a trial published last week found that an mRNA vaccine was more effective against symptomatic and febrile flu compared to the conventional vaccine. Another trial published last week also found that mRNA flu vaccines were more effective than conventional vaccines. Beyond effectiveness, mRNA vaccines can also be made more quickly, helping ensure that vaccines match circulating flu strains. Additional studies that include older people, those with coexisting illnesses, and school-age children, who face elevated risks, will be required to ensure broad efficacy across populations. 

A Phase 1 randomized controlled trial found that a single dose of the ChAdox1 Rift Valley fever (RVF) vaccine was safe, tolerable, and elicited a strong immune response in 30 adults in Uganda, where RVF—a neglected, mosquito-borne disease that is considered a significant public health threat and a priority for vaccine development—is endemic. The trial was led by researchers at the Uganda Research Institute and the London School of Hygiene and Tropical Medicine Research Unit in Uganda and provides the first evidence supporting the vaccine from a trial in an endemic setting. While the vaccine could potentially be transformative for RVF prevention, further research is needed that follows participants for a longer period and includes a larger group of participants, including children, pregnant women, and immunocompromised people. Last week at the American Society of Tropical Medicine and Hygiene annual meeting, Medicines for Malaria Venture and Novartis shared the results of a Phase 3 study testing a new malaria treatment, known as GanLum, finding that the treatment was highly effective at treating malaria, including drug-resistant cases, and could also block disease transmission. GanLum was found to be 99.2 percent effective in curing patients, more effective than standard artemisinin-based combination therapies, the gold-standard malaria treatment introduced more than 20 years ago, whose use has been undermined since the emergence of partial resistance. The developers say that, pending regulatory approval, the new treatment could be rolled out within the next few years. South African pharmaceutical company Biovac is launching trials of a cholera vaccine, which, if it proves successful, could become the first vaccine developed from start to finish on the African continent. Africa faces the brunt of the global cholera burden but is almost entirely reliant on vaccines made internationally, which has become increasingly challenging in recent years as cases have risen sharply around the world and vaccine stocks have diminished. The African Union has committed to increasing the proportion of routine vaccines used in Africa that are manufactured on the continent from just 1 percent now to 60 percent over the next 15 years, an effort triggered by the access challenges African countries faced during the COVID-19 pandemic. 

The World Health Organization's (WHO's) TB Vaccine Accelerator Council recently published a new report calling for action to ensure equitable access to future tuberculosis (TB) vaccines currently in the pipeline. While the only licensed vaccine for TB is 100 years old and has limited effectiveness in adolescents and adults, as of September, there are 16 candidate vaccines in clinical development, six of which are in Phase 3 trials. WHO estimates that a vaccine for adolescents and adults that is at least 50 percent effective could avert up to 76 million TB cases and 8.5 million deaths over 25 years. However, as the report claims, global demand could far exceed supply in the initial years after a vaccine is approved because there is no designated funding for such a rollout in low- and middle-income countries most affected by TB, which are already facing significant funding shortfalls. In anticipation of these potential bottlenecks and barriers to access, the report identifies six solutions to encourage countries with a high burden of TB, manufacturers, and other funders and stakeholders to start preparing now for the rollout to ensure future vaccines can reach people who need them faster. In a Phase 1 randomized controlled trial, an experimental intranasal vaccine against multiple H5N1 avian flu strains generated a broad immune response, demonstrating the potential of such a vaccine to play a major role in preparing for outbreaks of emerging viruses with evolving strains, as H5N1 continues its worrying spread. The University of Maryland research team tested the vaccine against a placebo in 40 adults between 18 and 45, finding that the vaccine was safe, well-tolerated, and stimulated immunity at various doses. One group received a vaccine dose combined with an adjuvant, an ingredient used to trigger a stronger immune response, and their immune systems were better able to neutralize infected cells for longer, suggesting that the use of an adjuvant could be a promising approach that might allow for lower doses, which could stretch limited vaccine supplies in the event of an outbreak. Last week, IAVI published new findings from the first-in-human Phase 1 clinical trial of its Lassa virus vaccine candidate, which show that one dose of the vaccine triggers robust and long-lasting immunity and is safe. There are no vaccines or treatments currently licensed against the dangerous illness, which causes thousands of deaths in endemic West Africa and has been designated as a priority pathogen with pandemic potential. The trial enrolled 114 volunteers in Liberia and the United States. The candidate, now undergoing a Phase 2a trial in West Africa, is currently the most advanced Lassa fever vaccine candidate in the pipeline and uses the same platform as Merck’s single-dose Ebolavirus vaccine, which is approved in more than a dozen countries.