Scientists Make Progress Toward a Safe, Effective Zika Vaccine

A biologist releases genetically modified Aedes Egypti mosquitoes in Piracicaba, Brazil, in February 2016. The modified mosquitoes, which cannot transmit Zika, compete with wild mosquitoes. Image Credit: Victor Moriyama/Getty Images

Zika virus has spread to almost 60 countries since early 2016. Almost 5000 cases have been identified in the United States, including more than 200 infections transmitted in Florida and Texas. Though the virus often causes only mild symptoms (or may not cause any symptoms at all), the link between Zika infection, microcephaly, and other developmental abnormalities has been strengthened with additional studies over the past year. However, a vaccine is still unavailable.

New research led by investigators at the University of Pennsylvania may move us closer to the goal of a safe, effective vaccine for the virus. The findings were published today in the journal Nature.

The scientists used a novel type of vaccine to immunize mice and monkeys, taking RNA molecules that code for viral proteins (messenger RNA, or mRNA). Because these RNA molecules would usually be quickly cleared by the body, the RNA in the Zika vaccine was modified by the addition of a modified nucleoside. The nucleoside is a nucleotide—the building blocks of DNA—lacking a phosphate group, which previous studies have shown helps to “hide” the mRNA from the host and allow replication. The mRNA was also packaged within lipid nanoparticles, encouraging protein expression. This vaccine therefore allows the mRNA to enter cells and induce production of the viral protein, causing a host immune response similar to that seen with a live virus vaccine. Researchers found that a single dose of the mRNA vaccine effectively protected animals against Zika virus.

Senior author Drew Weissman, of the University of Pennsylvania, relayed the advantages of this approach in a phone call with mental_floss. “The main advantages of our RNA vaccine is that only a single administration is needed. For all of the DNA and inactivated vaccines, they have to immunize twice to get protection, so we get much higher levels of neutralization with a single immunization. The only other vaccine that had protection after a single immunization was the live virus adenovirus vaccine.”

Live vaccines are difficult for a number of reasons, including potential side effects, and cannot be used in pregnant women—a main risk group for Zika infections due to the virus’s effects on the developing fetus. Weissman also noted the mRNA vaccine is inexpensive to produce, which could facilitate widespread use even in resource-limited countries.

Scientists hope to start human clinical trials with the Zika mRNA vaccine in 12 to 18 months. In the interim, additional experiments are planned in order to begin studying whether this Zika vaccine could potentially lead to increased illness with a related flavivirus: dengue. Dengue infection can lead to a phenomenon called “antibody-dependent enhancement,” where antibodies make disease worse instead of protecting the host from infection. There is concern that those vaccinated for Zika could experience more severe dengue infections in areas where both viruses circulate.

To examine whether their Zika vaccine could cause this effect, Weissman says, “We’re taking two approaches. We want to look at antibody-dependent enhancement between different flaviviruses. We’re also working on a combination vaccine that includes all of the flavivirus RNAs together, and the hope there is that with a single vaccine we can immunize against Dengue, West Nile, Zika, Japanese encephalitis, or whatever flaviviruses we want to include.”

Weissman and his collaborators are not the only ones hoping to move a Zika vaccine from the lab to the clinic. A number of different groups have worked to develop a Zika vaccine over the last year. A Phase I clinical trial, to investigate vaccine safety, began last August of a DNA vaccine developed at the National Institutes of Health. And while investigators are hopeful that one of the vaccines in development could be ready for use by 2018, vaccines for pregnant women may be delayed until several years after that, due to the difficulties of demonstrating safety in that population.

The components of the mRNA vaccine also provide hope the vaccine could be used during pregnancy. Weissman explains, “The RNA they use is identical to what’s in our bodies. The nanoparticles also contain mostly physiological lipids. We’ve seen no adverse events from any of our immunizations, so we’re thinking that will probably be easy to give to a pregnant woman.”

What’s the Difference Between Type 1 and Type 2 Diabetes?

The odds are pretty good that you know someone with diabetes. Affecting more than 30 million Americans, it's an incredibly common—and commonly misunderstood—condition.

The word diabetes comes from the Greek for "siphon"—a reference to the frequent and copious urination the condition can cause. The term was coined in the first century by ancient physician Aretaeus the Cappadocian, who vividly (and inaccurately) described the theory that "great masses of flesh are liquefied into urine."

Today we know a bit more about this illness, what causes it, and the forms it can take.

Diabetes is ultimately a hormone problem. The hormone in question is insulin, which helps the body convert glucose (sugar) into energy. Your pancreas releases a little dose of insulin into your bloodstream when you eat. The insulin tells certain cells to gobble up the glucose you've just added. The cells take in the sugar and put it to work.

Or at least that's how it's supposed to go. If you've got diabetes, the situation looks a little different.

Like rheumatoid arthritis or celiac disease, type 1 diabetes is the result of a person being attacked by their own immune system. In rheumatoid arthritis, the issue manifests in the joints; in celiac disease, it occurs in the gut; and in type 1 diabetes, it's the insulin-producing cells in the pancreas that are targeted by the immune system.

Little fluctuations in blood sugar that would breeze right through a healthy system can wreak havoc in the body of someone with type 1. People with type 1 must keep a very close eye on their glucose levels and take supplemental insulin, in shots or through a pen, port, pump, or inhaler, as blood sugar that goes too low or too high can cause serious complications and even death.

Type 2 diabetes is caused by an obstacle at the other end of the road. Someone with type 2 diabetes typically may have enough insulin to function, at least to start; the problem is that their body can't process it. Unused glucose builds up in the bloodstream and the body begins to need more and more insulin to see any effect.

Type 2 used to be known as adult-onset diabetes and type 1 as juvenile diabetes, but both kids and adults can and do develop both types. And while being overweight or obese does increase a person's risk of developing diabetes, thin people get it too. To complicate matters even further, researchers in Finland and Sweden recently identified five subgroups of diabetes, each with its own unique characteristics and risks for complications. Knowing which subgroup people fall into may improve treatment in the future.

And while we're myth-busting: The idea that diabetes is the product of eating too much sugar is a gross oversimplification. How you eat affects your body, of course, and a low-carb diet can help keep blood sugar in check, but diabetes can be caused by a lot of different factors, including genetics, medications, and other health conditions. (If you're on insulin, talk to a doctor before starting a low-carb diet, as low blood glucose levels can result if not done carefully.)

There's no common cure for diabetes—at least not yet. An artificial pancreas and other treatments for the immune system and pancreas cells are all in the works. In the meantime, both types can usually be managed with medication, diet changes, exercise, and a lot of doctor visits.

The Colorful Kit Helping Diabetic Kids Manage Their Injections With Temporary Tattoos

No kid looks forward to getting their shots, but for children living with type 1 diabetes, insulin injections are a part of everyday life. When Renata Souza Luque, a graduate from the Parsons School of Design in New York, saw how much of a toll the routine was taking on her 7-year-old cousin Thomas, she designed a product to make the process a little easier for kids like him. The result, Thomy, is a tool kit that aims to make insulin injections less intimidating to young diabetics, as Dezeen reports.

The brightly colored, easy-to-carry kit is designed for ages 4 and up, with an insulin pen specifically made to fit in a child’s hand. In addition to being easier for kids to hold and use, the Thomy pen is designed to be more fun than your average insulin injector. It has a thermochromic release valve, so that when it touches the patient’s skin, it begins to change color. The color-morphing doesn’t serve any medical purpose, but it provides kids with a distraction as they’re receiving the injection.

A purple insulin pen in an orange case
Renata Souza Luque

The kit also includes playful temporary tattoos to help kids figure out where their injections should go. Diabetics need to change the site of their injections regularly to prevent lumps of fat from developing under the skin, and for patients injecting themselves multiple times a day, keeping track of specific spots can be difficult. Kids can apply one of Thomy's temporary tattoos over their injection sites as a map for their shots. Each time they need an injection, they wipe off one of the tattoo's colored dots with alcohol and insert the needle in its place. When all the dots are gone, it's time to move on to a new area of the skin.

A child wipes at a temporary tattoo on his abdomen with a cloth.
Renata Souza Luque

Souza Luque originally created Thomy for her senior capstone project, and last year it was named a national finalist at the James Dyson Awards. Most recently, she presented the concept at the Design Indaba conference in Cape Town in late February.

[h/t Dezeen]


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