Reported on: September 11, 2012 14:19 PM
Reported in: Health
Dhaka, Sept 11 (UNB) - Scientists on Tuesday announced a major dengue vaccine breakthrough, with a candidate vaccine showing a 60%-90 % protection rate against three virus strains (DENV 1, 3 and 4) that causes the mosquito-borne disease.
The vaccine CYD-TDV was also found to be safe and welltolerated , with no side-effects on those who received it. No vaccine is now available to protect against dengue, and efforts to develop one have been hampered by the fact that dengue is caused by four viruses —DENV 1, 2, 3 and 4.
Dengue, which is now endemic in more than 100 countries, appears to be unique to humans. Hence, scientists cannot use animal models to test vaccine candidates.
Publishing their findings in the British medical journal The Lancet on Tuesday, Dr Derek Wallace from Sanofi Pasteursaid, "Our study constitutes the first-ever demonstration that a safe and effective dengue vaccine is possible. Further trials of CYD-TDV are currently under way in a number of different countries, and our hope is that the positive results of this trial will be confirmed by these larger studies, taking place in a wide range of epidemiological settings."
Researchers based in France and Thailand said they tested the effectiveness of CYD-TDV on a group of 4002 school children in Thailand - aged between four and 11 year old. Around 2,669 children were given the CYDTDV vaccine, while 1,333 were given a placebo. The vaccination schedule was three doses given six months apart (at 0, 6 and 12 months). Secondary tests then showed that the vaccine was effective against DENV 1, 3 and 4, but not on DENV 2, which appeared to be resistant to the effects of the vaccine in this trial.
Dr A C Dhariwal, head of India's National Vector Borne Disease Control Programme, said, "A vaccine will greatly benefit India where children are major victims of this disease. This candidate vaccine protects against dengue virus strain 1 which is the commonest and strains 3 and 4 which causes mild manifestations . However, it is the strain 2 that causes dengue hemorrhagic fever which is life threatening. And this vaccine does not protect against this strain."
Sanofi officials told TOI that phase III studies are presently going on involving over 31,000 volunteers in Latin America (Mexico, Colombia , Honduras, Puerto Rico and Brazil) and in Asia (the Philippines, Vietnam, Malaysia , Indonesia and Thailand).
Source: TNN/The Times of India