News / Health

Vaccines in Development to Protect Against Dengue Fever

A boy tries to outrun a man fumigating for mosquitoes in an effort to combat dengue fever, on the streets of Lahore, Pakistan, September 20, 2011.
A boy tries to outrun a man fumigating for mosquitoes in an effort to combat dengue fever, on the streets of Lahore, Pakistan, September 20, 2011.
Jessica Berman

The World Health Organization estimates that 2.5 billion people - more two-fifths of the world's population - are at risk of infection with Dengue fever, a mosquito-borne illness that in its worst form can cause death. Until now, efforts to develop a vaccine against the disease have been unsuccessful. Researchers say a couple of experimental vaccines are showing promise.

Since Dengue fever was first identified a half century ago, the incidence of the disease has grown dramatically. The World Health Organization says Dengue fever today is endemic in more than 100 countries, and more than 50 million people are infected every year.  

Scott Halstead, senior advisor to the Dengue Vaccine Initiative, an international consortium of medical research groups, said that fluid treatments for the disease have reduced mortality from the most severe form of the illness. But Halstead added that the rainy season in many parts of the tropics and subtropics - when Dengue-carrying mosquitoes are breeding and biting - is still a time of special anxiety because there is no specific medication or cure for Dengue fever:  

“While the mortality rate, in reality, is relatively low because of the availability of good hospital treatment, this is almost unlike any other major infectious disease,” said Halstead.

In its worst form, Dengue fever, also known as "breakbone fever," can cause severe internal bleeding, circulatory failure, shock, coma and death.

There are four related, but distinct, types of the Dengue virus that are transmitted by the bite of the Aedes aegypti mosquito. The difficulty in developing a vaccine, according to Halstead, is that a person may develop immune system antibodies against one type of virus, but would have no immunity against the other types.  

Halstead said that sets the stage for more serious infection later on.

“The antibodies that are left over from the first infection interact with the second type of the virus, and what we say is it “enhances” the infection; it makes it more severe the next time you’re infected with a different type of virus,” said Halstead.

Experts say it’s usually a second infection with a different Dengue virus that leads to the most severe and sometimes fatal form of the disease - Dengue hemorrhagic fever.

Two promising vaccine candidates now are in the works to protect against all types of Dengue virus. Both vaccines contain the four types of live but weakened viruses, designed to stimulate the body's production of neutralizing antibodies against all Dengue types.

French drug maker Sanofi-Pasteur has reportedly invested nearly $1 billion to develop a vaccine that is proving highly effective in phase-three human clinical trials in Thailand, the last step before regulatory approval. A second vaccine, being developed by U.S. drug maker Inviragen, also has proved to be safe and effective in phase-one human trials.

Dan Stinchcomb, Inviragen’s chief executive officer, said that despite the millions of dollars it has spent so far to develop the Dengue vaccine, the company hopes to keep it affordable.

“Our intention is to try to produce the vaccine at low cost so that we can provide it with help of funding to the poorest in need of the vaccine,” said Stinchcomb.

Progress on both Dengue vaccine candidates was reported at the recent meeting of the American Society for Tropical Medicine and Hygiene in Philadelphia, Pennsylvania.

You May Like

African States Push to Keep Boko Haram Offline

Central African telecoms ministers working with Nigeria to block all videos posted by Boko Haram in effort to blunt Nigerian militant group's propaganda More

Falling Oil Prices, Internet-Savvy Youth Pose Challenge for Gulf Monarchies

Across the Gulf, younger generations are putting a strain on traditional politics More

Philippines Call Center Workers Face Challenges

Country has world’s largest business process outsourcing, or BPO, industry, employing some one-million workers More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Supreme Court Hears Hijab Discrimination Casei
X
Katherine Gypson
February 25, 2015 11:30 PM
The U.S. Supreme Court has heard opening arguments in a workplace religious discrimination case that examines whether a clothing store can refuse to hire a young woman for wearing the headscarf she says is a symbol of her Muslim faith. Katherine Gypson reports from the Supreme Court.
Video

Video US Supreme Court Hears Hijab Discrimination Case

The U.S. Supreme Court has heard opening arguments in a workplace religious discrimination case that examines whether a clothing store can refuse to hire a young woman for wearing the headscarf she says is a symbol of her Muslim faith. Katherine Gypson reports from the Supreme Court.
Video

Video Falling Gas Prices Hurt Nascent Illinois Hydraulic Fracturing Industry

Falling oil prices are helping consumers purchase cheaper petroleum at the pump. But that’s made hydraulic fracturing or “fracking” less economically viable for the companies in the United States invested in the process. VOA’s Kane Farabaugh reports on one Midwestern town that was hoping to change its fortunes by cashing in on the next big U.S. oil boom.
Video

Video Fighting in Sudan's South Kordofan Fuels Mass Displacement

Heavy fighting in Sudan's South Kordofan state is causing hundreds of thousands to flee into uncertain conditions. Local aid organizations estimate as many as 400,000 civilians have been internally displaced since the conflict began more than three years ago, while another 250,000 have fled across the border to refugee camps in South Sudan. VOA's Adam Bailes reports.
Video

Video Lao Dam Project Runs Into Opposition

A Lao dam project on a section of the Mekong River is drawing opposition from local fishermen, international environmental groups and neighboring countries. VOA's Say Mony visited the region to investigate the concerns. Colin Lovett narrates.
Video

Video A Filmmaker Discovers Her Biracial Identity in "Little White Lie

Lacey Schwartz grew up in an upper middle-class Jewish family, in a town in upstate New York where almost everyone she knew was white. She assumed that she was, as well. Her recent documentary, Little White Lie, tells the story of how she uncovered the secret of her true racial background. VOA’s Carolyn Weaver has more on the film.
Video

Video Deep Under Antarctic Ice Sheet, Life!

With the end of summer in the Southern hemisphere, the Antarctic research season is over. Scientists from Northern Illinois University are back in their laboratory after a 3-month expedition on the Ross Ice Shelf, the world’s largest floating ice sheet. As VOA’s Rosanne Skirble reports, they hope to find clues to explain the dynamics of the rapidly melting ice and its impact on sea level rise.
Video

Video US-Cuba Normalization Talks Resume Friday

Negotiations aimed at normalizing diplomatic relations between the U.S. and Cuba resume Friday. On the table: lifting a half-century trade embargo and easing banking and travel restrictions. There's opposition in Congress, but some analysts say there may be sufficient political and economic incentives in both nations for a potential breakthrough this year. VOA's Mil Arcega reports.
Video

Video Pakistan's Deadline For SIM Registration Has Cellphone Users Scrambling

Pakistani cell phone users have until midnight Thursday to register their SIM cards, or their service will be cut off. While some privacy experts worry about government intrusion, many Pakistanis are just worried about keeping their phone lines open. VOA Deewa reporter Arshad Muhmand has more from Peshawar.
Video

Video Myanmar Warns Factory Workers to End Strikes

Outside Myanmar's main city Yangon, thousands of workers walked off their jobs earlier this month demanding a doubling of their wages, pay raises after a year and input from labor unions on industrial regulations. Since Friday, the standoff has grown more tense as police moved in to disrupt the sit-ins, resulting in clashes that injured people from both sides. VOA correspondent Steve Herman visited industrial zones which have become a focus of Myanmar's fledgling workers rights movement.
Video

Video Oscar Winners Do More Than Thank the Academy

The Academy Awards presentation is Hollywood’s night to reward the best movies from the previous year. It’s typically a lot of glitter, a lot of thank you’s, a lot of speeches. But many of this year’s speeches carried messages beyond the thank you's. VOA’s Carolyn Presutti takes a look.

All About America

Circumventing Censorship

An Internet Primer for Healthy Web Habits

As surveillance and censoring technologies advance, so, too, do new tools for your computer or mobile device that help protect your privacy and break through Internet censorship.
More