New Delhi: While dengue continues to claim lives, a vaccine to tackle the deadly vector-borne disease continues to elude India.

An indigenous dengue vaccine developed by the International Centre for Genetic Engineering and Biotechnology (ICGEB) in collaboration with Sun Pharmaceutical Industries Ltd is in the pre-clinical trial stage. Sanofi Pasteur, the vaccine division of the multinational pharmaceutical company Sanofi, too has developed a vaccine, which is currently under review by the regulator.

Dengue is a mosquito-borne disease that has spread rapidly across the world. It is caused by four closely related viruses—dengue viruses 1-4.

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“Sanofi Pasteur’s dengue vaccine is the culmination of over two decades of scientific innovation and collaboration, as well as 25 clinical studies in 15 countries, involving 40,000 volunteers around the world. Currently approved in 17 countries, it has proven to be efficacious against all four sero-types that cause the disease," said a Sanofi Pasteur India spokesperson.

According to the spokesperson, pooled Phase III clinical study results among at-risk populations of 9+ years old, over a 25-month period, revealed that the vaccine can prevent eight out of 10 hospitalizations, nine out of 10 severe dengue cases and has an overall efficacy rate of 65.6%.

However, the Indian Council of Medical Research (ICMR) is doubtful about the Sanofi Pasteur vaccine and claims that the introduction of the vaccine has the potential to do more harm than good.

“The government had deferred a decision on the vaccine. As we are going with the World Health Organization’s (WHO) guidelines, we found data gaps in baseline seroprevalence of the vaccine," said Dr Soumya Swaminathan, director general at ICMR. “We have to see if the vaccine’s efficacy is 30 % to 50 % which we will come to know in another 6 to 8 months with the ongoing baseline seroprevalence survey," she added.

According to health experts, at least 50% of the population should possess serotype immunity for the introduction of the vaccine. However, ICMR and National Vector-Borne Disease Control Programme (NVBDCP) don’t have sufficient data on this aspect.

“The ICGEB has designed a vaccine that doesn’t seem to enhance the disease... it only protects from the disease. The ICGEB is working on this for the last 10 years," said Freddy Castro, general manager, corporate communications, Sun Pharma India. Sun Pharma and ICGEB have, however, not given any time frame for the vaccine to be available.

Deaths due to dengue have increased in the past three years. According to the data available with the directorate of NVBDCP, the deaths recorded in 2014 were 137, the number was 220 in 2015 and around 245 deaths took place in 2016 across the country. Similarly, the number of dengue cases has also seen an upward trajectory. The number of official cases reported in 2014 was 40,571, 99,913 in 2015 and 129,166 in 2016.

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The worst-hit states have been Delhi, Punjab and Haryana in North India and Tamil Nadu, Kerala, Karnataka in South India. Maharashtra, Assam and other north-eastern states are also bearing the brunt of the disease.

The country has witnessed over 18,700 cases of dengue this year. Officials in the Union health ministry are attributing early onset of monsoon as one of the factors for the spurt in cases. The maximum number of cases has been reported in Kerala with 9,104, followed by Tamil Nadu with 4,174 till 2 July.

According to the figures available with the health ministry, Karnataka has reported 1,945 cases, Gujarat has reported 616, Andhra Pradesh 606 and West Bengal 469 till 2 July. The national capital has already recorded around 100 cases.