NPR reports on dengue vaccine progress

Nov 16 2010

NPR's "Shots" blog examines progress in the search for a vaccine to protect against the dengue virus.  

WHO "estimates that 2.5 billion people worldwide are at risk of getting dengue, and most of them are in Asia and Latin America," the blog writes. Annually, between 250,000 and 500,000 "severe cases of dengue and more than 20,000 deaths, typically from the worst permutation of the disease called dengue hemorrhagic fever [are reported], according to the World Health Organization. There is no treatment for any version of it," according to the blog, which also notes that cases have been detected in Florida and Texas.

The blog notes the recent launch of a Phase III clinical trial of an experimental dengue vaccine in Australia by drugmaker Sanofi-Aventis, which the blog writes "comes on the heels of what [the company] claims were several successful smaller trials in Asia and Latin America."

Finding a dengue vaccine has attracted the attention of other groups as well, according to the blog: "GlaxoSmithKline is conducting trials in Thailand, the United States, and Puerto Rico, while the U.S. government threw its hat into the ring with an announcement in August from the National Institutes of Health that it would start its own tests. And don't underestimate dark horse Brazil: its Instituto Butantan, best known for a snake farm where researchers milk snakes to make antivenoms, is now running its own trials with the NIH strains."

The post details the type of dengue vaccines currently in the works and includes comments by Jean Lang, who works on dengue vaccine development at Sanofi, and Peter Hotez of George Washington University, who is president of Sabin Vaccine Institute (Barclay, 11/13).

Meanwhile, "[s]cientists have released genetically modified mosquitoes in an experiment to fight dengue fever in the Cayman Islands, British experts said Thursday," the Associated Press reports. "It is the first time genetically altered mosquitoes have been set loose in the wild, after years of laboratory experiments and hypothetical calculations. But while scientists believe the trial could lead to a breakthrough in stopping the disease, critics argue the mutant mosquitoes might wreak havoc on the environment," the news service writes.

The article details how researchers tinkered with the DNA of mosquitoes to make them sterile in hopes of driving down the virus-carrying mosquito populations, and the studies that preceded the release of the mosquitoes into the wild. "[M]odeling estimates suggested an 80 percent reduction in mosquitoes should result in fewer dengue infections," according to the AP. "For years, scientists have been working to create mutant mosquitoes to fight diseases like malaria and dengue, which they say could stop outbreaks before they start," the news service adds.

The article also examines the potential environmental impacts of the GM mosquitoes and includes quotes by Luke Alphey, chief scientific officer of Oxitec Limited, the company that created the genetically-modified mosquitoes, Pete Riley, campaign director of GM Freeze, "a British non-profit group that opposes genetic modification," Andrew Read, a professor of biology and entomology at Pennsylvania State University, who was not involved in the research, and Yeya Toure, "who leads the World Health Organization's team on Innovative Vector Control Interventions" (11/12).

Concerns Mount About Deadly Dengue Outbreak In Brazil; Miami Reports First Case In 50 Years

As Brazil prepares to enter its "six-month rainy season" starting next month, during which "the frequent downpours will quickly turn trash piles, old tires, abandoned wells and even crumpled cigarette packs into containers of stagnant water where mosquitoes can breed," health officials there worry a recent spike in deadly dengue cases in the country will continue to grow, the AP reports in a separate article.

"The country saw a dramatic spike in the number of fatal cases this year: 592 were recorded from January through October, an increase of 90 percent over the 312 dengue deaths recorded during the same period last year, according to figures released Thursday by the Ministry of Health. And the resurgence of the Type 1 dengue strain largely absent in Brazil since the 1990s means that cases could continue to rise, officials say, stretching an overtaxed health care system," the news service writes. "To Brazil's north, neighboring Venezuela has also been confronting a dengue epidemic with about 100,000 diagnosed cases so far this year compared with 40,000 during the same period last year, according to recent Health Ministry figures," the news service adds.

The article examines the areas at greatest risk, including Rio de Janeiro - "where the recent closure of a major suburban hospital and the scheduled shuttering of two more has raised concerns that there might not be enough medical resources to deal with an epidemic" - and the efforts the Brazilian government is taking to educate the public about how to eliminate breeding grounds for mosquitoes to help contain the outbreak. The article includes comments by Luis Fernando Moraes, president of the Regional Council of Medicine of Rio de Janeiro, and Dan Epstein, a spokesman for the WHO (11/13).

In related news, a Miami health official on Friday confirmed its "first case of dengue fever in 50 years," Reuters reports. "The person diagnosed with the sometimes deadly mosquito-born virus has fully recovered after a brief hospitalization, said Liliana Rivera, a director at the Miami-Dade County Health Department.

Reuters writes that "[t]he case comes four months after officials announced more than 1,000 people in Key West, Florida, were believed to have been infected with dengue last year, marking its reemergence in the southeast U.S. state for the first time in decades." The piece notes that Florida health authorities have been on the watch for dengue outbreaks due to the recent dengue outbreaks in Latin America. Dengue "was largely eradicated in the United States in the 1940s but a few locally acquired cases have appeared, mostly along the Texas-Mexico border," according to Reuters (Gray, 11/12).