Are we underestimating HIV prevalence?

[Guest guest]

Dear Friends,

Most estimates of the number of persons infected with HIV are based on sentinel

surveys conducted on pregnant women who come in for ANC

checkups. However if HIV causes decreased fertility less women infected with the

virus would get pregnant. Thus the sentinel survey would give us lower estimates

than the actual.

A recent article presents data that shows that HIV may decrease

fertility and thus our surveys may be all wrong! I am posting the

abstract below: -

Abstract

Background: Most estimates of HIV prevalence have been based on sentinel

surveillance of pregnant women which may either under-estimate or over-estimate

the actual prevalence in adult female population.

One situation which can lead to either an underestimate or an overestimate of

the actual HIV prevalence is where there is a significant difference in

fertility rates between HIV positive and HIV-negative women.

Our aim was to compare the fertility rates of HIV-infected and HIV-uninfected

women in Cameroon in order to make recommendations on the appropriate

adjustments when using antenatal sentinel data to estimate HIV prevalence

Methods: Cross-sectional, population-based study using data

from 4493 sexually active women aged15 to 49 years who participated in the 2004

Cameroon Demographic and Health Survey.

Results: In the rural area, the age-specific fertility rates in both HIV

positive and HIV negative women increased from 15–19 years age bracket to a

maximum at 20–24 years and then decreased monotonically till 35–49 years.

Similar trends were observed in the urban area. The overall fertility rate for

HIV positive women was 118.7 births per 1000 woman-years (95% Confidence

Interval [CI] 98.4 to 142.0) compared to 171.3 births per 1000 woman-years (95%

CI 164.5 to 178.2) for HIV negative women.

The ratio of the fertility rate in HIV positive women to the fertility rate of

HIV negative women (called the relative inclusion ratio) was 0.69 (95% CI 0.62

to 0.75).

Conclusion: Fertility rates are lower in HIV-positive than HIV-negative women in

Cameroon. The findings of this study support

the use of summary RIR for the adjustment of HIV prevalence (among adult female

population) obtained from sentinel surveillance in antenatal clinics.

The article can be accessed at the link given below

http://www.biomedcentral.com/1471-2458/8/309/prepub

Regards,

Lt Col (Dr) Anil Paranjape, MD

Pune, India

e-mail: <anilvparanjape@...>