Estimating HIV in India
Aug 02, 2007

India has eliminated HIV from 3.2 million of its people in a year! Well... sort of.

Analysis of a recent in-depth survey reveals a lower number -2.5 million people instead of 5.7 million people- living with HIV in India today. The new estimate ratchets India down from being the most populous HIV positive nation in the world to being the third - after South Africa and Nigeria.

As an epidemiologist and a former consultant to the World Bank for AIDS in India, I have experienced the perplexing task of estimating and projecting HIV in a population. In 1996, my Indian colleague and I made a bold and dismal prediction in the prominent medical journal Lancet where we wrote, “We fear there will be over 10 million infected persons by the end of the decade (year 2000).”

I am not embarrassed to say we were wrong. In fact, I am elated to discover that we had grossly overestimated the numbers. But our logic and reasoning was sound. The question we wrestled with while estimating the number of HIV people in a nation is whether HIV would enter the general population including middle class shopkeepers, housewives, and civil servants; or if it would remain on the fringes among high-risk groups such as commercial sex workers (prostitutes), and their clients such as truck drivers.

I spent several years researching the HIV epidemic in India a decade ago. On a dusty one-lane highway connecting Madras (now Chennai) to Bangalore, I watched trucks zoom by. Young lanky men with dark complexions, wearing colorful lungis (a loincloth wrapped around the waist) stopped at truck stops for meals, rest and a commercial sexual encounter.

The rate of HIV among commercial sex workers (CSWs) had already risen to 30 percent by 1992 with a potential parallel rise among truck drivers. As we doctored patients in the sexually transmitted disease and HIV clinic, we began to see young women – the wives of the truck drives - presenting with HIV.

A few cases of HIV among rural women, whose only risk factor was sexual contact with their husbands, was like a canary-in-a coalmine. We feared HIV was spreading into the general population - from the CSWs to their male clients, to the clients’ wives, and then to their children. We dreaded that a calamity was in the making in India – as has happened in Africa.

Imagine if HIV enters the general population of 1 billion people! If one percent of the population became infected, this would translate to 10 million people with HIV. In Africa, men and women have two or more occasional but regular sexual partners, and the speed at which HIV spread was alarming. If the pattern were to repeat in India the virus would spread like a brush fire, with HIV rates rising from 2% to 30% in the general population. However, if the virus circulated only within the high-risk groups then HIV would smolder like cinders with rates rising slowly in the general population, as seen in the United States.

The question that epidemiologists intensely debated was, “How will HIV spread in India?” My colleagues and I suggested it would be like in Africa, and so we came up with an estimate of 10 million. Recent survey data, however, show that the pattern is closer to that in the United States, with HIV remaining in pockets of high-risk populations with limited spread into the general population.

As I look back, I realize there are distinct advantages to being an unintentional alarmist. One garners greater attention from the media, politicians and international donor agencies when there is a potential brush fire in the backyard. With this attention, much has changed over the decade: unprecedented international support, energized non-government organizations, and tremendous governmental efforts for AIDS education, prevention, and treatment.

Luckily, even with the lower estimate, Bill Clinton and Bill Gates’s foundations are committed to funding their AIDS initiatives in India, and government official are steadfast in their efforts to control the spread of the virus.

Epidemiologists are like prophets who predict the future with limited information. When predicting a calamity, it is heartening if they are wrong!

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