New Delhi: The annual number of dengue fever cases in India may be "almost 300 times greater" than officially reported, inflicting a massive $1.1 billion economic burden on the country each year in medical and other expenses, says a study.
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 Indian Council of Medical Research's (ICMR) Centre for Research in Medical Entomology (CRME) in Madurai, Tamil Nadu, is the first to use systematic empirical data to estimate both the disease burden and the direct and indirect costs of dengue in India.
Until now, the reported data indicated that there was an annual average of 20,000 laboratory confirmed cases. But the new estimated results were striking.
"We found that India had nearly six million annual clinically diagnosed dengue cases between 2006 and 2012 - almost 300 times greater than the number of cases that had been officially reported," claimed lead study author Donald Shepard, health economics professor at Brandeis University.
To determine the annual number of dengue patients in India, the researchers collected data on patients who had been hospitalized with the disease in Madurai, Tamil Nadu, during a three-year period (2009-2011).
They then used that data, along with less complete disease surveillance data from 18 other states and information from a panel of dengue experts, to calculate a national estimate for annual dengue cases, including ambulatory cases.
"We found that the overall annual economic cost of dengue in India is about $1.11 billion annually or $0.88 per year for every person in the country," said study co-author Yara Halasa, health economics researcher at Brandeis University.
"This study provides a valuable insight into the dengue disease burden in India. Dengue, in addition to inflicting pain and suffering, also extracts a significant social and economic toll on India," said Alan Magill, president of the American Society of Tropical Medicine and Hygiene which publishes the American Journal of Tropical Medicine and Hygiene that carried the paper.
“In recent decades, dengue outbreaks in India have become larger and more frequent, with a greater number of severe cases and deaths. Good data on the incidence and cost of the illness have been lacking due to gaps in how information on individual cases is collected and reported,” said Narendra Arora, executive director of INCLEN.
According to Brij Kishore Tyagi, senior investigator from CRME, “understanding the full extent of the economic and disease burden of dengue in India is necessary to help policymakers and public health officials prepare for and control future outbreaks of the disease”.
To estimate the cost of each dengue case, the researchers analysed the medical records of 1,541 dengue patients who had been treated in 10 public and private medical college hospitals across India from 2006 through 2011.
Gaps in those data were then filled in through a survey of 151 patients who had received care at a medical college hospital in Mumbai in 2012 and 2013.
India is believed to have more cases of dengue than any other country in the world.
In 2013, India's National Vector Borne Diseases Control Programme reported that the country had experienced an annual average of 20,474 dengue cases and 132 dengue-related deaths since 2007.
But infectious disease experts believe those official numbers likely reflect only a small fraction of actual cases.