Back to basics in HIV prevention: focus on exposure

Pisani et al. (2003) advocate using evidence on the source of
incident HIV infections to prioritise resources [1]. The paper focuses on
HIV surveillance, and rightly argues that country-by-country monitoring of
behaviour and patterns of incident infection would better inform the
prioritisation of resources. However, it falls short when discussing the
broader implications of the distributions of new HIV infections presented,
as it does not acknowledge the limitations of current options to respond.

For example, in Cambodia, in part because of the successes of condom
promotion among sex workers, in 2002 over 60% of incident infection were
due to ‘heterosexual sex with a partner at higher risk of infection’, and
the authors call for prevention strategies to reduce transmission between
spouses who may previously have been exposed to HIV through buying and
selling sex. Likewise, substantial proportions of incident infection in
Honduras, Kenya and Russia were identified as being from heterosexual sex
with a partner at risk. However, although high levels of condom use can be
achieved in commercial and some casual sexual relationships, the desire to
conceive and the common association of condoms with a lack of intimacy
make their consistent use in long-term partnerships difficult to achieve.

In representative household surveys of women in 14 African countries, less
than 7% reported condom use in the last sex act with their main partner.
Surveys of sex-workers in 4 states of India and of street sex-workers in 5
cities of Vietnam generally found that less than 40% reported condom use
in their last non-commercial sex act (an exception is in Maharashtra
brothels, where 70% reported condom use)[2]. Similarly, only 17% of
injecting drug users in Togliatti, Russia reported condom use with their
regular partner [3].

This highlights the urgent need for additional prevention methods for
use in spousal and other long-term partnerships. Options include
microbicides - gels, creams, and suppositories - that when used vaginally
could reduce transmission of HIV (and potentially other sexually
transmitted infections)[4]. Over 60 products are at different stages of
development, including 17 in clinical trials. With sufficient funding one
could enter Phase III effectiveness trials later this year, and an
additional four could enter Phase II expanded safety trials in late
2003/2004 [5]. As microbicides could be promoted as a hygiene product for
use in spousal partnerships and could potentially allow conception, they
would be an important addition. Their development should be prioritised.

Charlotte Watts, Anna Foss

Health Policy Unit,
Department of Public Health and Policy,
London School of Hygiene and Tropical Medicine

References

1. Pisani E, Garnett GP, Brown T, Stover J, Grassley NC, Hankins C.
et al. Back to basics in HIV prevention: focus on experience. BMJ
2003;326: 1384-7.

2. Foss A, Watts C, Vickerman P, Kumaranayake, L. Are people using
condoms? Current evidence from Sub-Saharan Africa and Asia and the
implications for microbicides. Mimeo Report, HIVTools Research Group,
London School of Hygiene and Tropical Medicine June 2003.

3. Rhodes T, Lowndes CM, Judd A, Mikhailova L, Sarang A, Rylkov A.
et al. Explosive spread and high prevalence of HIV infection among
injecting drug users in Togliatti City, Russia. AIDS 2002;16: F25-F31.

4. Stone A. Microbicides: a new approach to preventing HIV and other
sexually transmitted infections. Nature Rev Drug Discov 2002;1(12): 977-
985.

5. Harrison P. Personal communication to Foss A. March 2003.

Competing interests:  
CW and AF receive partial salary support from research grants from the EU, the Programme for Appropriate Technologies in Health, and the UK MRC that support mathematical modelling of microbicide impact and its determinants