Chiangrai Times – French Drug Maker Sanofi has announced that its dengue vaccine has proved effective against three of the four dengue virus strains in clinical trials conducted in Thailand.
The mosquito-borne disease, also known as “breakbone fever,” is a threat to nearly three billion people in the world. Although the search for a dengue vaccine has been going on for nearly 70 years, it has intensified in the past two decades.
Sanofi’s reportedly successful vaccine depends on an antibody response. The positive results of the clinical trials in Thailand have already led the company to invest 350 million Euros in a new factory in France.
The Sanofi Pasteur dengue vaccine candidate is a live attenuated vaccine, given as 3 doses, 6 months apart (month 0, month 6, and month 12 of the trial).
The safety and efficacy trial was conducted in 4,002 children aged 4 to 11 years in Thailand, as a partnership between Sanofi Pasteur and the Mahidol University under the patronage of the Thai Ministry of Public Health in Muang district of the Ratchaburi Province.
Sanofi say the vaccine generated antibody response for all four dengue virus serotypes and early analysis of the trial results show evidence of protection against three of the four virus serotypes circulating in Thailand.
The company say they are still analysing the results to understand why the vaccine failed to protect against the fourth virus serotype “in the particular epidemiological context of Thailand”.
The most important news, they say, is the results confirm the “excellent safety profile” of the experimental vaccine.
The full data is now being reviewed by experts and public health officials, and the intention is to publish the results of the study in a peer-reviewed journal for scrutiny by the scientific community later this year.
The rate of dengue, a mosquito-borne infection found in tropical and sub-tropical regions, has risen dramatically around the world in recent decades, mostly in urban and semi-urban areas. It is also spreading geographically: a recent outbreak in Florida shows that dengue is now reaching continental USA outside the endemic areas of Hawaii and Puerto Rico.
There are currently 50 to 100 million people infected every year, and over 40% of the world’s population, that is over 2.5 billion people, are estimated to be at risk, says the World Health Organization (WHO).
There are four related but distinct viruses that cause dengue fever. The infection causes flu-like symptoms, and occasionally develops into hemorrhage and shock, known as severe dengue, a leading cause of serious illness and death among children in some Asian and Latin American countries.
There is currently no effective treatment for dengue fever, and the only way to control its spread at present is to control the mosquito.