Again, the ANC survey that UNAIDS depends upon is the culprit.
I think a lot of apologies are in order.

And why is it so easy to admit that AIDS figures in India have been
hugely overestimated, but when you do the same thing for the very
same survey type in AFRICA, the world's too small a place and
the sky will fall.

Alex

http://www.aidsmap.com/en/news/B046D04C-5A15-47E6-9A21-CE38CD88BC42.asp

Edwin J. Bernard, Wednesday, August 23, 2006

India's HIV prevalence rates have been grossly overestimated and
require substantial downwards revision, according to a late-breaker
presentation at the Sixteenth International Conference in Toronto
on Thursday August 17th. Population-based HIV prevalence
estimates in Andhra Pradesh, the south Indian state thought to
have the highest prevalence of HIV, were found to be
two-and-half times lower than estimates based on sentinel
screening at antenatal and sexual health clinics.

At the end of 2005, India's National AIDS Control Organisation
(NACO) estimated that there were 5.21 million people living with
HIV, although this figure had been criticised by some as an
underestimate.

Indeed, UNAIDS estimated that the number of people living
with HIV in India at the end of 2005 was closer to
5.7 million - higher than South Africa's estimated 5.5 million -
although it suggested a lower and upper range of 3.4 million
and 9.4 million, respectively.

NACO extrapolates data from the public health system - primarily
women testing for HIV during antenatal care, as well as anonymous
surveillance from sexual health clinics - in order to estimate HIV
prevalence in India, and until now no population-based study had
systematically examined the validity of this extrapolation.

Investigators from the Administrative Staff College of India and
the Institute of Medical Sciences in Hyderabad sampled 13,838
adults aged 15-49 from 66 rural and urban clusters that represented
the 4.5 million adults in the Guntur district of south India's
Andhra Pradesh state, which is thought to have the highest
HIV prevalence in India.

Demographic data were obtained from a total of 12,617 individuals
(91.2% of those sampled), and dried blood spots obtained at the
same time were tested for HIV antibodies, p24 antigen and HIV
RNA. The results were then compared with the HIV estimates
from NACO's sentinel surveillance data.

The investigators found that the adjusted HIV rate in adults was
1.72% (95% CI, 1.35-2.09%), with a slightly higher prevalence
in men (1.74%; 95% CI, 1.27-2.21%) than women (
1.70%; 95% CI, 1.36-2.04%). Prevalence was higher in urban
settings (1.89%; 955 CI, 1.39-2.39%) compared with rural
settings (1.64%, 95% CI, 1.10-2.18%).

Using a standard of living index (SLI), the investigators found
that HIV prevalence rates were twice as high in people who
were in the lower half of the SLI (i.e. poorer), compared with
those in the upper half (2.58% vs 1.20%, respectively).

Around 23% of pregnant pregnant women had accessed antenatal
care through the public health system in the previous two years.
Significantly, they discovered that very poor women were
over-represented, which resulted in an unusually high HIV prevalence
rate (3.61% versus 1.08% of pregnant women who did not use
the public health system). This would have skewed the
surveillance-based data which found antenatal clinic HIV
prevalence to be 3%.

The investigators calculated that their population-based estimate
for the Guntur district is 45,925 adults after adjusting for
underrepresented high-risk groups. In contrast, NACO's
surveillance-based estimate was 112,635 adults. In other
words, population-based HIV prevalence was two-and-a-half
times lower than the sentinel surveillance data.

By applying the investigator's population-based estimates to
the entire state of Andhra Pradesh, this results in a reduction
from 1.44 million adults living with HIV to just over half a million.

Lalit Dandona, of the Centre for Human Development in Hyderabad,
presenting, concluded that NACO's method for estimating HIV
prevalence grossly overestimates HIV in all south Indian states -
home to around three-quarters of India' HIV-positive
population - and which have a similar pattern of public health
system use by the poorest people. Therefore, NACO's current
HIV estimate of 5.21 million for India should be revised
downwards by a substantial amount.

Reference
Dandona L et al. A population-based study suggests
that the HIV estimate for India needs major revision.
Sixteenth International AIDS Conference, Toronto,
abstract ThLB0107, 2006.