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Penn Medicine Kicks off Zika Vaccine Trial as Athletes Head to Rio 2016


This week, more than 10,000 athletes from 206 countries around the world will start competing in the 2016 Summer Olympics in Brazil. But with looming concerns about the Zika virus and other infectious diseases in the region, it won’t only be the athletes that will be under the microscope — it will also be the mosquitos.


Concerns over Zika and the risks it poses to pregnant women have prompted some public health advocates to call for the games to be postponed or moved. However, the World Health Organization (WHO) and other experts have declared the games safe, noting that because August is actually winter in Brazil there will be much less exposure to mosquitoes. In addition, athletes will spend most of their time in climate controlled environments and will have access to insect repellant and other precautions.

But that hasn’t stopped several athletes, male and female, from citing Zika as a serious enough threat to keep them from competing. Even soccer star Hope Solo expressed concern, telling Sports Illustrated that if the games had taken place in February (summertime in Brazil) she likely wouldn’t have attended. 

“I would never take the risk of having an unhealthy child," Solo told the magazine. As of this week, Solo is scheduled to compete.

But how concerned should Olympians and other attendees be about Zika?  Not enough to sit out the games, according to Stephen J. Gluckman, MD, medical director for Penn Global Medicine.

“Of course, if someone is very worried about how Zika could impact their family, they should stay home, but for most of the athletes and others attending the 2016 Olympics, the risk is actually very small and with the proper precautions, it can be managed,” he said

About 80 percent of people who become infected with Zika have no symptoms, while the rest tend to only have mild symptoms that last for several days to a week. In rare cases, though, the virus has been linked to a nervous system disorder that can cause muscle weakness and sometimes paralysis. It poses the biggest danger during pregnancy, when infection can cause a range of severe fetal abnormalities, including microcephaly, which causes infants to be born with abnormally small heads that can cause physical and mental disabilities.

It’s clear that the growing attention around Zika is not only because more are cases being reported, but because the number of cases are, in fact, on the rise.

“Sometimes is just takes the right combination of susceptible people, population density, and the availability of the vector, in this case, the Aedes mosquito, to cause infections to increase,” Gluckman said.

Zika is not a new disease, but until recently it has mostly been found in Micronesia and Africa. The first case of Zika was actually documented in Uganda in 1947 and it was officially recognized as a disease in 1952.

“The Olympics are just one reason so much attention has been focused on the Zika virus,” Gluckman said. “It’s also creeping closer to our own borders here in the United States, which is the source of a lot of the recent concerns.”

On Friday, Florida health officials confirmed four locally transmitted cases of Zika virus, marking the first time the virus has been found to be transmitted via infected mosquitoes within the United States. All other U.S.-based cases up to now have been in people who traveled to Zika-affected regions or who acquired the disease from sexual partners. Thus far, the outbreak has infected three men and one woman in Miami-Dade and Broward counties in Florida. Health officials are trapping and testing mosquitoes in the area and will continue to monitor for more infections.

The amount of uncertainty around Zika is one of the many reasons researchers at Penn are partnering with the Wistar Institute and Inovio/GeneOne Pharmaceuticals to develop a Zika vaccine.

This phase I clinical trial, which began in July, will be the first Zika vaccine study in humans. It will enroll approximately 40 participants (one-third of them at the Perelman School of Medicine at the University of Pennsylvania) who will receive a DNA vaccine injection. Unlike other common vaccines in which a virus protein is injected, this vaccine injects DNA into the skin, where a large amount of immune cells exist in the body. The DNA is then uptaken by cells that will produce a particular Zika virus protein. The hope is that antibodies against that Zika protein will develop to prevent infection.

“We do not inject the virus itself, so there is no risk of participants becoming infected with Zika from the vaccine,” said Pablo Tebas, MD, a professor of Infectious Diseases at the Perelman School of Medicine and a principal investigator on the trial.

“This is a phase 1 study, so our goal is to make sure that the vaccine is safe. As part of the study, we will start collecting information about how immunogenic it is, meaning how many antibodies the participants develop after the vaccination,” Tebas said. “We need to do these types of studies before opening larger studies in the Caribbean and other areas of the world with a higher risk of Zika infection in order to demonstrate that the vaccine is able to prevent real infections.”

The Olympics themselves are providing a unique opportunity for researchers to study Zika. In July, the U.S. Olympic Committee (USOC) announced a partnership with the U.S. National Institutes of Health (NIH) to study athletes and USOC staffers who will be traveling to Brazil in the hopes of answering some basic questions about Zika that could lead to a better understanding of the virus and its long-term effects. 

Zika isn’t the only health concern for travelers heading to South America. 

“Zika has some real risks, but for most travelers, they are much more likely to encounter other health challenges, especially food and water-borne diseases, traveler’s diarrhea, typhoid, or even malaria,” Gluckman said.

And the risks in Brazil, like most developing countries, are not uniform. If travelers stay along the coast and in major urban settings, the likelihood of contracting Zika or another disease are much lower than if they head to the interior of the country, where diseases such as yellow fever and malaria are still prevalent.

So what’s the biggest takeaway for athletes and others as they get ready to compete at Rio 2016?

“Be careful and take precautions, just like you would when traveling to any foreign country,” Gluckman advises.

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