Breakthroughs Blog: Vaccines

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. A single, high-dose cholera vaccine—Vaxchora—could be an effective tool in controlling outbreaks more rapidly, according to new research from the University of Maryland School of Medicine. The current cholera vaccine consists of two doses of the inactivated virus administered over two weeks, but researchers believe they have developed a stronger, single dose vaccine approach that will be more effective in combatting outbreaks because it can be deployed more rapidly and easily. Researchers plan to further study how this vaccine may help curb outbreaks early before they become widespread and its potential use in preemptive vaccination. They also plan to study the vaccine’s effectiveness in children under the age of five—one of the most burdened demographics of cholera. Researchers at the Indiana University School of Medicine discovered a way to prohibit malaria-causing parasites from shielding themselves against treatment in mice, which could open new avenues for drug development. While the most common malaria medicines are effective at reducing the level of parasites in the blood, some of these parasites enter a latent stage during treatment, allowing them to survive through the treatment and eventually reinfect the individual after he or she has ceased taking medication. This process makes treating malaria more challenging and dangerous, particularly among individuals who do not have consistent access to therapies. Researchers discovered the molecular mechanism that leads to these parasites entering the latent stage and how to inhibit it, which they hope will lead to medicines that prevent treatment failure and subsequent reinfection. Researchers may have developed a urine test to detect tuberculosis (TB) in patients, according to a paper published in Science Translational Medicine. Current TB diagnostics include skin and culture tests that require a high level of expertise to carry out correctly. A new method, like a rapid urine test, will allow lower skilled health workers in TB-endemic areas to carry out quick and effective TB diagnostic tests. A study of 42 individuals in Peru found the test had greater than 95 percent sensitivity—or the ability to correctly identify those with the disease. Furthermore, researchers reported this test can be used to diagnose TB at any stage and among HIV-negative populations—populations who usually have more mild concentrations of the bacteria in the body.  

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. The release of antibiotics into the environment is a significant environmental threat, according to a new United Nations Environment Programme report. The presence of antibiotics have been found in soil deposits, lake and river sediment, and wastewater facilities around the world, suggesting industrial, human, and pharmaceutical disposal leads to traceable amounts of antibiotic compounds in the environment. This issue alarms experts because even minimal traces of antibiotics may lead to the continued evolution of antimicrobial resistant bacteria. While more research is needed on the consequences of antibiotics in the environment, experts suggest various strategies to help mitigate the problem including deploying improved methods to treat wastewater, treating animal waste before using it as fertilizer, and improving antimicrobial stewardship. An Army-developed Zika vaccine candidate (ZPIV) performed well across three Phase 1 clinical trials, according to new findings published in The Lancet. The three studies were designed to elicit information on background immunity, vaccine dosage, and vaccine schedule in adult populations. A total of 67 participants received two injections four weeks apart, and researchers found more than 90 percent of participants who received the ZPIV vaccine had an immune response to the virus. The Army developed the vaccine candidate in response to the 2015 outbreak, noting the need for a Zika vaccine not only to advance global health, but also to protect US service members and their families. Countries are restricting use of the world’s only dengue vaccine—Dengvaxia— following an announcement by developer Sanofi Pasteur raising safety concerns. The company discovered, from data analysis, that the vaccine could raise the risk of a deadly form of dengue for people who had not been exposed to the virus prior to vaccination. In response, the Philippines ceased an ongoing, mass immunization campaign, and Brazil tightened restrictions on the vaccine. While Sanofi stressed there were no reported deaths related to the dengue vaccine, they believe more severe cases of dengue may occur if an immunized individual, who was not previously infected before receiving the vaccine, is then subsequently infected with dengue. This rare complication leaves children at a higher risk of contracting the severe form of dengue, as they are less likely to have been exposed to infection before receiving the vaccine. Dengue sickens hundreds of millions of people and kills more than 20,000 every year, underscoring the need for a safe, effective, vaccine.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week A tech nonprofit, WeRobotics, is seeking to deploy drones to deliver hundreds of thousands of sterile mosquitoes into Zika hotspots across Latin America to assist with mosquito population control. Existing research suggests releasing sterile mosquitoes into the wild may eventually reduce populations by as much as 90 percent, though actual mosquito introduction has proven challenging. To solve this, WeRobotics developed small, temperature-controlled drones designed to deploy mosquitoes in rural and hard-to-reach locations, ensuring all affected areas receive the sterile mosquitoes. The drone’s cool temperature leaves the mosquitoes in a deep sleep state, protecting them during the journey, and the drone then releases the mosquitoes from a controlled height to ensure they do not die from impact. WeRobotics plans to deploy these drones soon and will educate local communities about the project. The World Health Organization (WHO) recently announced that about 11 percent of all medicines circulating in low- and middle- income countries are substandard or counterfeit. WHO estimates between 72,000—169,000 children may die from pneumonia and 116,000 may die from malaria every year after receiving falsified or substandard products, suggesting this is a widespread and alarming problem in the world’s poorest countries. Experts believe majority of these cases remain unreported, compounding existing issues with counterfeit or substandard medicine monitoring across affected countries. This is the first time WHO has assessed in-depth the global scope of the problem. In 2013, the agency set up a voluntary global monitoring system for substandard and fake drugs, which has helped bring to light the extent of the issue. An estimated 50 million doses of antibiotics are prescribed for typhoid every year, with overuse or misuse of these drugs contributing to the global rise of antibiotic-resistant bacteria. In the city of Karachi, Pakistan—a typhoid-endemic country—antibiotic resistance is rising by 30 percent per year, and 100 percent of typhoid cases are expected to be multi-drug resistant by 2020. A new typhoid vaccine may be the solution to this growing problem. The typhoid conjugate vaccine (TCV) is more effective in preventing typhoid than its predecessor and may protect individuals for up to five years—longer than the previous vaccine. Most importantly, TCV may be given to children under the age of two, expanding the level of coverage to infants who are in critical need of a vaccine. With rising levels of antibiotic-resistant bacteria, having an effective and inclusive typhoid vaccine may save thousands of lives.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. An individual’s immune response to the Zika virus—rather than the virus itself—may be the cause of severe nerve-related complications like Guillen-Barrè, according to a recent Yale University study. Researchers explored the spread of the Zika infection in mice who lacked a key antiviral response to the virus and found that immune cells known as CD8 T cells flood the brain during infection. While these T cells limit the virus from infecting nerve cells, they also attack the brain’s neurons, leading to complications like Guillen-Barrè, which may cause paralysis. These results suggest that suppressing immune response to the Zika virus may be a promising approach to preventing these complications. Developing new antiretroviral (ARV) drugs and improving early diagnosis are two critical steps to end the HIV and AIDS epidemic by 2030, according to a UNAIDS report. While HIV and AIDS still remains the leading cause of death among women ages 15–49 globally, there has been notable and sustained momentum toward ending the disease. Approximately 21 million people globally currently receive life-saving ARV treatments, with the number of people under treatment nearly doubling in the past five years. Significant cost reduction of ARV therapies as well as the sustained use of treatments have led to a 48 percent decline in AIDS-related deaths, from 1.9 million in 2005 to 1 million in 2016. UNAIDS officials emphasized that despite this progress, the world must not become complacent, as 17 million people are still waiting for treatment and a decline in global support could lead a rebound in the epidemic. Researchers at The University of Texas, El Paso have developed a potential vaccine for cutaneous leishmaniasis, a painful neglected tropical disease with an estimated 700,000 to 1 million new cases annually. While leishmaniasis predominantly affects the poorest countries in the world, the disease has also impacted over 2,000 US service members stationed in Afghanistan and Iraq, as well as residents in Texas and Oklahoma, where the disease occurs naturally. Researchers found that the vaccine candidate resulted in a 96 decrease in leishmaniasis-associated lesions and an 86 percent protection rate against the disease in mice studies. Though more research is necessary, researchers feel optimistic about this formula. There is no current vaccine for the disease in humans and current treatment options available are limited, painful, and lengthy.