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. 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.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. A resurrected malaria prevention strategy—seasonal malaria chemoprevention—saved an estimated 40,000 lives in 2015 and 2016, according to new research. The strategy involves giving children a dose of antimalarial drugs monthly during the rainy season—the season with the highest incidence of malaria—to prevent the disease. Researchers and public health professionals were initially skeptical of this technique when applied in real-world settings since it requires thousands of local aid workers to deliver malaria drugs to rural and hard-to-reach areas, but recent results have shown reductions in malaria prevalence similar to those seen in clinical trials in areas deploying the strategy. While historical and recent studies suggest this technique is effective, there are signs this method will only work for a limited time before existing drugs fail because of resistance, meaning alternative solutions must continue to be explored. As the world gets closer to eradicating polio, a funding crisis looms for many countries. Funding for the Global Polio Eradication Initiative is scheduled to be halved in 2019 and expire the following year, except in the most high-risk countries. A reduction in polio funding will leave countries with depleted resources, straining their capacity to vaccinate against other life-threatening diseases and conduct surveillance activities. Today, polio funding supports health workers that also deliver routine immunizations as well as 70 percent of all global funding for surveillance. Also, as polio transmission rates move toward zero, global strategies must be implemented to maintain eradication, including using the safer injectable polio vaccine for up to ten years following eradication, which will be more difficult to achieve if polio resources are strained. At the close of the first Global Ministerial Conference on Ending Tuberculosis, 75 health ministers agreed to take committed action to end tuberculosis (TB)by 2030. Ministers met in Moscow, Russia over two days to discuss and strategize solutions for TB. They concluded with a pledge to take action on four fronts: (1) move to achieve universal health coverage, (2)mobilize domestic and international investments to close gaps in implementation and research, (3) advance research and development for new tools to tackle TB, and (4) build accountability by tracking and reviewing progress in ending TB. Ministers also vowed to take increased action to minimize the risk and spread of antimicrobial resistance.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past we. A quick and inexpensive test may make it easier to diagnose and distinguish betweenZika and dengue. Both viruses produce the same NS1 protein, making it is impossible for current NS1 protein-based diagnostic tests to discern between the two. To overcome this problem, scientists developed a set of antibodies produced from immune cells that can distinguish between an NS1 protein produced by the Zika virus and an NS1 protein produced by the dengue virus. In a study, the diagnostic test was able to discern between the two viruses, even when there was a lowNS1 protein count in the body. While further studies are required, this tool could become an essential diagnostic tool in areas of the world where both Zika and dengue are endemic. A series of papers exploring the impact of group B streptococcus (GBS) was published in Clinical Infectious Diseases. GBS is an infection a mother can pass to her fetus that can cause septicemia, meningitis, and even death. The papers argue that there are 410,000 cases of GBS every year with 147,000 associated stillbirths and infant deaths. There is also a major disparity of GBS cases between developed and developing countries: Many at-risk women in developed countries receive prophylactic antibiotics during labor, but those resources are often not available to women in developing countries. Scientists believe the solution to this problem is a GBS-specific vaccine, which could save over 100,000 infant lives.This vaccine may be critically important as scientists believe “immunizing expecting mothers is a potentially groundbreaking approach that could dramatically reduce the number of maternal and child deaths.”There is currently no GBS vaccine available, but there are candidates in development. The US Environmental Protection Agency approved the release of lab-reared “killer mosquitoes” to help reduce the population of disease-carrying mosquitoes in certain American states. A biotechnology start-up based in Kentucky—MosquitoMate—will rear these mosquitoes with a lethal bacterium that impedes reproduction and release the infected males into the wild. When the infected males mate with wild females, the offspring will not be viable due to malformed chromosomes. Over time, disease-carrying mosquito populations will dwindle. Other countries, including Brazil, have tried this method and found it successful, suggesting this could be a solution for countries severely affected by mosquito-borne illnesses. This method is also a “non-chemical way of dealing with mosquitoes,” so offers an alternative to pesticide-based vector control.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. GAVI, the Vaccine Alliance has partnered with the wearable tech company Kushi Baby to bridge the immunization gap for infants in low-income communities. About 1.5 million children die every year from vaccine-preventable illnesses, and one in three do not receive the immunizations they need simply because health professionals "do not know they exist." This partnership will provide children with a wearable necklace technology that remotely tracks and updates their immunization history. The technology allows health professionals to more accurately provide the supplies needed when traveling to rural communities and reach children in need of immunization. This year 1,500 infants in Northern India received the necklaces. The partnership has a goal of increasing distribution to 5,000 necklaces by the end of the year. A new vaccine under development may lower pneumonia incidence and mortality rates by targeting additional strains of the bacteria, according to a new study published in Science Advances. Current pneumonia vaccines only target the most common strains of the illness, but this vaccine candidate targets dozens of additional strains. The candidate may also help maintain the body’s microbiome—a collection of healthy bacteria often killed during the immunization process—by “attack[ing] [bacteria] only if it breaks away from the colony to cause an illness.” The World Health Organization Strategic Advisory Group of Experts on Immunization (SAGE) has recommended a new typhoid fever vaccine that has demonstrated up to 87 percent effectiveness during a clinical study. This typhoid vaccine is the first of its kind licensed for use in children under two years of age. SAGE recommended the vaccine be given to children 6 months old and that catch-up campaigns be administered to immunize children between the ages of 6 months and 15 years of age. With drug-resistant typhoid growing in typhoid-endemic communities, the vaccine will also be a valuable tool in combatting antimicrobial resistance.