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Earlier this month, French drug maker Sanofi announced that the world's first dengue vaccine would be available in the second half of 2015. The announcement came after the company's vaccines division, Sanofi Pasteur, published detailed results of the final landmark phase III clinical efficacy study in Latin America in The New England Journal of Medicine. Analyses showed 95.5 per cent protection against severe dengue and an 80.3 per cent reduction in the risk of hospitalisation during the period of the study. The study confirmed the results observed during the 25-month active surveillance period of the first phase III efficacy study conducted in Asia, highlighting the consistency of results across the world.
Dengue, also known as breakbone fever, is a mosquito-borne tropical disease caused by four distinct virus serotypes. The disease is a threat to almost half of the world's population. In some cases, the disease develops into dengue haemorrhagic fever, which leads to a sharp fall in blood platelets and can be life threatening. Currently, there is no specific treatment available for dengue. According to the World Health Organisation (WHO), there are almost 100 million cases of dengue the world over every year. But the figure of the overall number of people affected by the disease is not known. Last year, more than 500,000 people were hospitalised for dengue fever and 2.5 per cent of these cases proved fatal. WHO has set the target of reducing dengue mortality by 50 per cent and reducing morbidity by 25 per cent by 2020.
Based on data provided by the National Vector Borne disease Control Programme, 2013 saw 75,000 cases of dengue in India, with 167 deaths. India reports more cases of dengue than any other country. However, according to an online study by the American Journal of Tropical Medicine & Hygiene, the number of dengue cases in India are 282 times more than what are actually reported. The alarming number of cases reported also has an adverse effect on the Indian economy, imposing a burden of $1.1 billion every year.
This vaccine breakthrough is expected to come as a major relief for India. When Sanofi announced the landmark test results, medical experts were unsure of its successful implementation in the country. However, tests carried out by the Paris-based drug maker in five Indian cities - Delhi, Bengaluru, Kolkata, Ludhiana and Pune - have shown positive results. The vaccine, tested on adults aged 18-45, has been deemed safe. In India, where cleanliness and proper sanitation are woefully neglected, the vaccine will prevent millions of people from contracting the infection. "Dengue is a major health concern in India. Along with the loss of lives, the disease has major economic implications as well. This vaccine will hope to change that," says a Sanofi spokesperson.
For the vaccine to be successful, it has to work in different conditions and demographics. So will the vaccine work in India? According to Mukesh Mehra, senior consultant at Max Super Speciality hospital in New Delhi, the vaccine's initial test results are an indication that it will help in reducing the danger of dengue significantly. "The fact that Sanofi has been able to develop a vaccine for different regions is an outstanding achievement," says Mehra. "This vaccine was badly needed for a country like ours. Even if it does not guarantee 100 per cent prevention, it will act as a great immunity booster."
Given the disease's common flu-like symptoms, most dengue cases go undetected. A person with a strong immune system can easily overcome dengue. Only 10 per cent of patients infected by the virus get hospitalised. Mehra says that the real challenge will be to administer the vaccine to the high-risk population. "The government needs to formulate a policy to administer the vaccine to such a large population," he says.
However, the vaccine's high cost may prove to be the biggest hurdle. Although, Sanofi hasn't announced the price of the vaccine yet, Mehra feels that it will not come cheap. "Scale is one problem. But the cost is a bigger problem. Dengue needs to be controlled. The government must find a way out," says Mehra.
