Developing a Dengue Vaccine

Today's article about challenges of developing a dengue vaccine.

In the eighteenth century America, came to be called "break bone fever," ample evidence of the excruciating pain of the experience of patients. Dengue fever, according to the World Health Organization, is the rapid spread of the virus disease transmitted by mosquitoes throughout the world.

Over the past five decades, the incidence has increased 30 times. The disease is now endemic in over 100 countries by two-fifths of the world population is at risk. Not only increases the number of cases the disease spreads to new areas, but explosive outbreaks are occurring, the General Council takes note.

Overall, an estimated 50 million to 100 million people are infected each year and 5,00,000 of them - a very high percentage of children - to develop forms of deadly disease.

Over the years, dengue has become endemic across much of India, says U.C. Chaturvedi, a virologist who has studied the disease for many years. Most people who become infected will recover without any problem. But to keep the death rate down, it is essential that signs of severe forms of the disease, such as a rash and small bleeding spots on the skin, be recognised. Such people must be immediately admitted to a hospital that can provide supportive treatment, he says.

Without proper treatment, death rates can approach 10-30 per cent, he notes. But mortality can be kept to less than one per cent with sufficient medical care. In the process, however, hospitals can become heavily burdened when a large number of people become infected during outbreaks, he adds.

‘Major health problem'

“The spread of dengue virus throughout the tropics represents a major, rapidly growing public health problem with an estimated 2.5 billion people at risk of dengue fever and the life-threatening disease, severe dengue,” observed Daniel P. Webster of the John Radcliffe Hospital in the U.K. and others in a review paper published in the Lancet Infectious Diseases in 2009. A safe and effective vaccine, they said, was urgently needed.

But while vaccines are available against yellow fever and Japanese encephalitis, caused by closely related viruses, a vaccine against dengue has proved remarkably hard to develop. Nevertheless, a number of different approaches to producing vaccines against it are being tested, from live but weakened viruses to killed viruses, and giving bits of viral protein. Some of these are already in clinical trials.

Vaccine for dengue

Here's about vaccine for dengue.

No dengue vaccine is available. Recently, however, attenuated candidate vaccine viruses have been developed. Efficacy trials in human volunteers have yet to be initiated. Research is also being conducted to develop second-generation recombinant vaccine viruses. Therefore, an effective dengue vaccine for public use will not be available for 5 to 10 years.

Prospects for reversing the recent trend of increased epidemic activity and geographic expansion of dengue are not promising. New dengue virus strains and serotypes will likely continue to be introduced into many areas where the population densities of Ae. aegypti are at high levels. With no new mosquito control technology available, in recent years public health authorities have emphasized disease prevention and mosquito control through community efforts to reduce larval breeding sources. Although this approach will probably be effective in the long run, it is unlikely to impact disease transmission in the near future. We must, therefore, develop improved, proactive, laboratory-based surveillance systems that can provide early warning of an impending dengue epidemic. At the very least, surveillance results can alert the public to take action and physicians to diagnose and properly treat DF/DHF cases.