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 study recently published in Science Immunology found that mice infected with malaria had shorter thigh bones than their control counterparts by ten percent, suggesting if the same effect takes place in human, children could suffer stunted growth due to malaria infection. Researchers found the malaria parasite left behind waste which killed the mice’s bones, resulting in the disruption of cells responsible for breaking down and rebuilding bones. The researchers found a possible solution, however. By giving the mice a derivative of vitamin D, they were able to stimulate more bone regrowth and suppress the breakdown of bone. Fifteen children have died in a rural South Sudanese village after one needle was used over the course of multiple days with a vaccine that was not stored properly. Almost 50 individuals fell ill after being inoculated on the same day, resulting in 15 deaths due to either sepsis or a related toxicity. According to the World Health Organization (WHO), the series of events were a result of a lack of training and qualification from the individual administering the vaccines, who failed to adhere to WHO immunization safety standards. South Sudan has been affected by a years-long civil war which has reduced the ability to carry out health care services. Immunization coverage has fallen from 77 percent before the conflict down to 44 percent.  The National Institute of Allergy and Infectious Diseases and the National Institutes of Health have sponsored a phase 1-2 Chikungunya vaccine trial at three different sites around the United States, including Emory University, Baylor College of Medicine, and the University of Iowa in Iowa City. The study will focus on three groups, one receiving a high-dose vaccine, one receiving a low-dose vaccine, and a control group. The results will help establish the best dosage and timing for the vaccine. If this trial is successful, the vaccine could become an important tool to combat the Chikungunya endemic in Eastern Africa and prevent the spread of cases within the United States.  

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. CRISPR-cas9, a revolutionary gene editing tool, has been hailed a breakthrough device for microbiologists and geneticists—but not without certain reservations. In a study recently published in Nature, researchers attempting to target and edit genetic blindness in mice analyzed nucleotides—the single-unit building blocks for DNA—in the edited and control mice in order to evaluate success of the tool. CRISPR successfully targeted the alleles—or mutated nucleotides—causing blindness in the mice, but the editing also caused 1,600 off-target, unpredicted mutations, including 100 “large changes” in the DNA structure. This is important because single-nucleotide mutations are associated with many diseases, such as sickle-cell anemia, Huntington's disease, cystic fibrosis, and more. The researchers stressed that more needs to be done to study off-target mutations before CRISPR can be considered risk-free, but that the outlook for the tool is still positive, as any scientific tool has side effects. The science behind creating an effective vaccine that is capable of completely eradicating a disease is complex and hard-won. The only vaccine that has been used to successfully eradicate a disease in humans is the smallpox vaccine. Edward Jenner used cowpox, a similar but much less dangerous bovine variation of the disease, to create a successful vaccine against smallpox—and now scientists are going back to that methodology in an attempt to eradicate malaria. Scientists plan to genetically modify a rodent-variation of the malaria parasite to then use on healthy human volunteers. The hope is that the variation will result in a protective response in humans. The first phase of trials will begin in 2018 and will involve studying initial protection against the disease, with future phases focusing on continued efficacy of the vaccine. Motivated by a lack of awareness and funding for tuberculosis (TB), Médecins Sans Frontières, or Doctors Without Borders, launched a clinical trial, entitled  TB PRACTECAL, aimed at finding a new, improved treatment for drug-resistant TB. The trial, which officially launched in January 2017, is testing an innovative combination of TB drugs that will only need to be taken for six months. Current treatments for drug-resistant TB are physically and emotionally arduous, painful, and only successful about 50 percent of the time, which is why shorted, improved treatment regimens are needed. The first set of trial results is expected to be released within two years with final results within four. If successful, the organization hopes the new treatment will be rolled out in countries around the world and mark an important step forward in combatting the global epidemic.

In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week. A recent Congressional hearing on Zika has revealed that there is a lack of consensus regarding the diagnosis and treatment of the virus. Furthermore, only approximately 25 percent of babies born from women who have been exposed to Zika receive the necessary follow-up to evaluate their children for developmental defects. Such follow-up is critical—Zika can cause defects in the infant months after birth. As a result, the impact of Zika may be underestimated, leaving public health professionals uneasy about proposed budget cuts by the Trump Administration, which could exacerbate the treatment and reporting challenges that characterize the current outbreak. Chagas disease, colloquially known as "kissing bug disease," is more deadly than previously thought due to underreporting of the disease. Going undiagnosed while carrying Chagas can elevate the risk of death, primarily due to associated heart problems that will develop over time. Chagas disease initially mimics symptoms of the flu, often causing a misdiagnosis and lack of proper treatment, and it can lie symptomatically dormant for years, silently causing irreparable damage to the heart. There is currently no effective vaccine against the disease. The Democratic Republic of Congo’s (DRC) Ministry of Health has approved the use of an experimental Ebola vaccine to combat the outbreak. The vaccine, though experimental, proved to be highly effective in clinical trials. Details of how the vaccine will be deployed have not been announced yet, but if further cases are confirmed, it will likely be given to contacts and contacts of contacts of those with a confirmed case. So far, there have only been two confirmed cases, but over fifty suspected cases.

Researchers at the University of Cape Town discovered a compound that blocks the cycle of malaria within the human body, regardless of its drug-resistant status. The compound acts a preventative tool as well as a treatment for those infected with malaria, as it can block transmission and prevent infection. The compound, MMV390048, began phase I clinical trials in 2014, but subsequent data has not yet been published. The drug will enter phase II clinical trials this year in Ethiopia, and it is hoped this drug will be on the market within the next ten. With the world circling in on polio eradication, global public health professionals have run into a major obstacle that makes ridding the disease incredibly complicated: A vaccine shortage. There currently isn’t enough injectable polio vaccine for the world to use, as demand is so high. There isn’t enough of the vaccine in production for each child to receive two shots, which is what researchers suggest to protect against contracting polio. An alternative is the oral polio vaccine, but due to its heightened risk of complications, professionals believe this vaccine will soon be phased out. While polio vaccine manufacturing may be ramped up to treat children in the next few years, it is essential that health care professionals continue to vaccinate children ten years post-eradication to ensure there is no resurgence of the disease. Funders, including the Gates Foundation, are now putting efforts toward the next surge in vaccine demand, and hope to overcome this obstacle to reach global eradication of polio once and for all. An outbreak of Ebola has been confirmed in the Democratic Republic of the Congo (DRC), and health researchers around the globe are working to distribute an experimental vaccine. While the outbreak is contained due to the geographic isolation of the cases, the WHO and Gavi are still working quickly toward an effective and globally approved vaccine that can be used in future outbreaks. The DRC has not requested a vaccine at this point in time, but these organizations are prepping for when the country requests it, or for if the outbreak spreads past the DRC. The vaccine is experimental, and requires special modes of transportation, yet proved incredibly successful during the Ebola outbreak of 2014.