Monday, November 3, 2014

dengue vaccine CYD-TDV

Dengue vaccine tested on Indian adults, found safe
Kounteya Sinha,TNN | Nov 2, 2014, 09.30 PM IST
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LYON (FRANCE): The world's first dengue vaccine CYD-TDV has passed the crucial India test and could be available in the country as early as by the end of next year.

In an exclusive interview to TOI, the vaccine makers Sanofi Pasteur revealed that their first study of the vaccine on Indian adults (aged 18-45 years) across five sites in India — Delhi, Ludhiana, Bangalore, Pune and Kolkata found the vaccine "safe and immunogenic in Indian adults" with results comparable to other clinical studies in Asia.

The study showed that 87% of Indian adults in the trial were positive to dengue at enrolment, confirming the significant endemic nature of the vector borne disease in the country.

Sanofi also announced the results last week at the joint annual conference of Indian Society of Malaria and Other Communicable Diseases & Indian Association of Epidemiologists.

Dr Nicholas Jackson, Sanofi Pasteur's chief of research and development for the dengue vaccine program told TOI in an exclusive interview: "We are in contact with the Indian authorities to assess the best registration pathway for our vaccine. Based on the positive results we now have from two phase III studies conducted in 10 countries across Asia, Latin America and the Caribbean, we will prepare to submit the vaccine for licensure in endemic countries in the first quarter of 2015."


The Sanofi Pasteur vaccine research and development laboratory in Lyon, France. (Getty Images photo)

Dr Jackson added, "The Indian authorities requested us to perform a study in adults, which we did. This is highly significant as it is the first study of our vaccine in India on adults. The results will be an important part of our database as we consider additional clinical trials in India with our vaccine and the results will also play a part to support our licensure application in India."

Dengue is a threat to nearly half of the world's population. It is endemic in over 100 countries. One person is hospitalized every single minute with dengue.

"WHO has the target to reduce morbidity by 25% and mortality by 50% by 2020," he said adding, "We just completed a large epidemiology study in India. Around 2,591 persons were enrolled in a community-based, cross-sectional sero-prevalence study across eight geographically distinct urban, peri-urban and rural sites in India. In children aged 5 to 10 years, our study showed that 60% of children had evidence of prior exposure to dengue."
"At seven sites, this ranged from 58.2% to 80.1%. The highest seroprevalence was observed in Mumbai (80.1%), and lowest in Kalyani in eastern India (23.2%)," he said.


A dengue patient having treatment in ICU at a Delhi hospital. (Getty Images file photo)

In addition, Sanofi is also planning to conduct new cohort studies to further estimate the incidence of dengue disease in India.

Dr Jackson said, "This new study will be conducted in four sites from next year. We believe it is critical to understand well the burden of dengue disease in India. The results observed suggest dengue transmission intensity in these sites is comparable to other highly endemic countries of Southeast Asia and speaks to the significant burden of disease in children in India."

Earlier CYD-TDV — the first dengue vaccine candidate to reach phase 3 clinical testing has shown 88.5% efficacy after three doses against severe disease dengue haemorrhagic fever which leads to hospitalization for over half a million people (mostly children) every year.

Once administered, the vaccine also provided 67% protection against dengue-associated hospitalization.


Aedes aegypti mosquitoes that spread dengue virus. (AFP photo)

Researchers found that the vaccine gave low protection (35%) against DENV 2 strain, but more than 75% protection against DENV 3 and 4, and 50% against DENV 1.

The vaccine was generally well tolerated.

A total of 647 serious adverse events were reported, 402 (62%) in the vaccine group and 245 (38%) in the placebo group.

Overall, the vaccine has shown moderate protection (56%) against the disease in Asian children, according to new research published in Lancet last month.

There is no licensed vaccine available to treat or prevent dengue fever and efforts to develop one have been complicated by the fact that dengue is caused by four distinct dengue viruses, and a vaccine must target all four serotypes (DENV 1-4).

Lead author Dr Maria Rosario Capeding, from the Research Institute for Tropical Medicine in the Philippines said, "Our results suggest that vaccination with CYD-TDV can reduce the incidence of symptomatic dengue infection by more than half and importantly reduced severe disease and hospitalizations. This candidate vaccine has the potential to have a significant impact on public health in view of the high disease burden in endemic countries."


A woman covers her face as a municipal corporation worker in New Delhi fumigates the area to prevent mosquitos from breeding. (Getty Images file photo)

India alone accounted for around one-third of all infections. Of the 96 million apparent infections, Asia records 70% of the burden.

The vaccine will be a boon for India.

Scientists recently said that the number of people getting affected with dengue in India could actually be almost 300 times higher than what is officially reported by the country's ministry of health. The conclusion was made by none other than the Indian Council of Medical Research — the government's primary body for all medical and scientific research.

The new study published in American Journal of Tropical Medicine & Hygiene says that there are nearly 6 million more dengue cases in India than the official annual tally.

The government however says there is an annual average of 20,000 laboratory confirmed cases.

The study, led by researchers at Brandeis University's Schneider Institute for Health Policy in Waltham, Massachusetts, the INCLEN Trust International in New Delhi and the ICMR's Centre for Research in Medical Entomology (CRME) in Madurai calculated that dengue's economic burden on India totals $1.11 billion annually; roughly the same amount India spends each year on its national space program.

To calculate dengue's economic burden, the researchers found that the total direct medical cost to India was $548 million per year, or about $94.85 per patient. Given that the average dengue case lasts about two weeks that figure breaks down to $6.77 per patient per day. Dengue is therefore more expensive to treat in India than tuberculosis.

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