Myths on AIDS prevalence: Editorial of Economic Times

[Guest guest]

Myths on AIDS prevalence

[MONDAY, APRIL 23, 2007 02:09:17 AM]

HIV/AIDS figures in India will have to be drastically slashed as a

result of more accurate HIV data. But United Nation's Programme on

AIDS (UNAIDS) continues to stand by its exaggerated guesstimates that

distort the magnitude of the Indian epidemic.

In recent years, the joint UNAIDS has been forced to reduce estimates

of the number of persons living with an HIV infection (HIV

prevalence) in many countries in sub-Saharan Africa and the Caribbean

by half or more as a result of more accurate HIV data but as of 2007,

HIV prevalence estimates in many Asian countries remain grossly

overestimated — with India officially top of the world league.

There is a widespread misconception among vocal AIDS activists that

all official HIV prevalence estimates are grossly underestimated —

most news reports carry the inevitable: " However, most AIDS experts

believe that the actual HIV numbers are much higher than the official

estimate. "

In fact, the official numbers may be grossly overestimated. The

primary method for estimating HIV prevalence in a country like India

is to use serological survey data, testing blood collected from

selected samples for HIV antibodies. Major problems with this method

are the limited number of " sero-survey " studies that might be

representative of specific populations or subgroups, and the wide

variability in estimates of the size of groups with risky HIV

behaviour.

HIV sentinel surveillance (HSS) is the routine collection of blood

samples from specific " sentinel " populations to monitor the trend of

HIV infection rates in these sentinel populations. Although HSS

systems were not designed to provide data for making HIV prevalence

estimates, they have been used in India for this purpose primarily

because there were no other HIV data available.

However, HSS data are usually heavily biased by inclusion of mostly

urban " sentinel sites " where the highest HIV prevalence might be

found: this bias is significantly present in the Indian data. In late

2006, Lalit Dandona and colleagues released results of a well-

designed population-based (randomly selected cluster samples of urban

and rural populations) HIV sero-survey in the high HIV-prevalence

district of Guntur in Andhra Pradesh.

Their findings indicate that the official national Indian estimation

methods using data obtained from sentinel antenatal clinics and the

unique Indian assumptions regarding other sexually-transmitted

disease ratios had led to gross overestimation.

Based on their study and extrapolation to other states with high HIV

prevalence, they came up with a national estimate of three to 3.5

million. However, if Dandona's correction of almost 60% lower is

applied to the total national estimate of five to six million, the

revised national HIV prevalence estimate may be just a bit over two

million

UNAIDS will most likely try to argue that population-based type

surveys in Asian populations may underestimate HIV prevalence, and

this may in fact be the case. However, all of the population-based

HIV studies carried out in 2006 in India should cut by at least half

and possibly more the official estimates by UNAIDS or the Indian

National AIDS Control Organisation (NACO).

Projection of future HIV prevalence is even more uncertain than

estimation of current HIV prevalence. In the newly released 2006

revision of the estimates and projections of population by the UN

Population division, projected HIV prevalence in 2025 in India was

reduced to less than five million — a projected 20% decrease from the

current UNAIDS estimate of almost six million.

This is in stark contrast to the UNPOP's HIV projection for India in

their 2002 revision that forecast a marked future increase in HIV

prevalence. The most unrealistic projection for India came from the

US National Intelligence Council in 2002 when they projected that HIV

prevalence might be close to 20 million by 2010. Not to be outdone,

the UNAIDS Independent Commission in Asia has just said infections

could more than double in Asia in the next five years.

Unrealistically high HIV-prevalence estimates and projections in many

Asian countries are being exposed as, at best, naive efforts of well-

meaning AIDS programme advocates and, at worst, the work of

AIDS " experts " who ignore or deny the more credible lower estimates

and projections, to support their own political, social, economic, or

personal agendas. But for such a serious infection as HIV, a

prevalence of two to three million still represents a huge public

health problem for India.

Inflating HIV numbers may in the short term help UNAIDS to garner

more support for AIDS programmes, but can also result in an eventual

backlash and withdrawal of public and policymaker support when such

inflated numbers cannot be defended. Right now NACO is proposing a

five-fold increase in funding but this increase is based on grossly

inflated HIV estimates: only with the most accurate HIV estimates and

projections can limited resources be allocated to the right people in

the right places.

Chin

(Professor Chin is a former chief of the Surveillance, Forecasting,

and Impact Assessment unit of WHO's Global Program on AIDS)

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