Select Committee on Health Minutes of Evidence

Memorandum by John Imrie, Royal Free and University College Medical School (SH 102)


1.1  Background:

    —  Sexual behaviour, specifically the rate of partner change and the types of sexual active that people engage in, are essential factors in determining the transmission of STI and HIV.

    —  Behavioural surveillance involves monitoring and measuring patterns of sexual behaviour in populations in order to understand changes in STI and HIV incidence and prevalence.

    —  Behavioural surveillance is important in relation to prevention as it provides essential information to determine what types of interventions are needed and the follow-up data to gage their effectiveness.

1.2  Main sources of behavioural surveillance data:

    1.  Routine reporting from health services settings to the CDSC (eg KC-60).

    2.  Repeat cross-sectional and longitudinal studies (eg NATSAL)

    3.  Ad hoc and one-off studies of sample populations from the most affected groups (e.g. HIV positive gay men, African ethnic minorities) (eg Mayisha Study of African Communities in Camden and Islington).

  Routine surveillance data collected by CDSC is largely limited to demographic characteristics, likely route of STI transmission/sexual orientation and HIV status. Limited sexual behaviour, HIV status and HIV testing history data are collected in some programmes.

  Repeat cross-sectional studies—The frequency with which these studies are repeated in part indicates the degree to which changes in study populations' sexual behaviour is likely to impact on trends in STI and HIV epidemiology.

  Ad-hoc studies are used to study specific populations provide detailed information but are usually of limited longer term value because they only measure at one point in time and have limited ability to detect change over time.

1.3  Current sources of behavioural surveillance data according to population group:

1.3.1  General Population

    —  Routine data from CDSC (eg KC-60, Survey of Prevalent HIV Disease Seen in Clinics (SOPHID), Unlinked Anonymous Prevalence Monitoring Programme)

    —  Cross-sectional studies—National Survey of Sexual Attitudes and Lifestyles (NATSAL).

1.3.2  Homosexually Active Men

    —  Routine data from CDSC (eg KC-60, Survey of Prevalent HIV Disease Seen in Clinics (SOPHID), UA Prevalence Monitoring Programme)

    —  Three ongoing behavioural surveys (2 exclusively London focused, 1 nationally focused (ie England and Wales) that includes London).

    —  One London surveys includes anonymous saliva testing for HIV linked to self-completed questionnaires

    —  Several smaller studies examining limited populations (eg men with diagnosed HIV infection attending clinical services).

1.3.3  Sub-Saharan African Communities

    —  Routine data from CDSC (eg KC-60, Survey of Prevalent HIV Disease Seen in Clinics (SOPHID), UA Prevalence Monitoring Programme)

    —  Collection of ethnicity data in relation to HIV testing and STI diagnosis has been reported since 1996.

    —  Included in wider cross-sectional population surveys (ie NATSAL) however numbers recruited were too small to make generalisable comments.

    —  No ongoing behavioural surveillance studies in place.

1.3.4  Injecting drug users:

    —  UA Prevalence Monitoring Programme routinely collects basic behavioural data specifically regarding injecting practices and sharing of needles.

    —  Some qualitative studies have considered the sexual behaviour of IDU in relation to HIV transmission

    —  No ongoing behavioural surveillance studies in place, unlikely that they are needed.


2.1  Homosexually Active Men

  There is increasing prevalence of HIV in this group, partly due to better survival, but also due to continued transmission. Over the passed six years researchers have observed :

    —  Increases in new diagnoses of STI in homosexually active men, and particularly in men with diagnosed HIV infection and those of unknown serological status (see figure 1 and figure 2).

    —  No overall increase in the numbers of sexual partnerships either regular or casual.

    —  Nationally, a reduction in the proportion of men who report having engaged in anal intercourse (AI) in the last year, but this is not the case in London.

    —  Among men who report engaging in AI, an increase in the proportions who report routinely using condoms.

    —  Equally, among men who report engaging in AI, an increase in the proportions reporting having had unprotected anal intercourse (UAI), with both regular and casual partners. The proportion who report any AI in the last year ranges from about 70-82 per cent, while the proportion who report having had UAI exceeds 50 per cent in all of the surveys. There is considerable variation according to survey, recruitment site, age and HIV status.

    —  An increase in the proportion of men who report that they only engaged in sero-concordant (i.e. both partners of same HIV status) unprotected anal sex (UAI).

    —  The greatest changes in the behaviours carrying the greatest risk for transmission have been observed among the youngest men, usually the under 25's and among men with diagnosed HIV infection.

    —  The proportion of men who have ever had an HIV test is subject to considerable regional and age group variations. Nationally, among men aged less than 20 is less than one-third have ever tested. In London approximately two-thirds of men have ever tested compared to only about half in the North West region and in Wales. There has been a significant in increase in most areas, particularly in London, in the proportion who report that their last HIV test was within the last year.

    —  More homosexually active men are attending GUM services, however, the proportion who reported having an STI diagnosed in the last year is also rising. There is no uniform pattern nationally. In London, men with diagnosed HIV infection were nearly twice as likely to have had an STI diagnosed in the last year than either HIV negative or untested men.

    —  The prevalence of HIV in community sample of gay men in London has not changed significantly in the last two years. The community HIV prevalence in the Brighton pilot study was 12 per cent and almost 8 per cent in Manchester. However these prevalence figures should be interpreted with caution because of the relatively small samples recruited in the pilot site cities.


    —  Effective anti-HIV treatments have had a major impact on the lives of people living with HIV.

    —  Many people now feel better, and therefore feel more inclined to have sex.

    —  However the impact of anti-HIV drugs on the observed changes in sexual behaviour, particularly homosexually active men, is much less clear.

    —  Numerous studies internationally have shown conflicting results about whether the availability of effective treatments has lead to more reporting of higher risk sexual behaviours.

    —  One UK study has shown that men on treatments are less likely to report sexual behaviours that increase the likelihood of onward transmission.

    —  Among all homosexually active men other factors also seem to be involved, including: alcohol and recreational drug use, psycho-social factors including depression and low self-efficacy (ie belief in one's ability to perform a specific behaviour (use a condom) in a given situation) and prevention fatigue (ie tired of the same messages).

    —  In the case of men with diagnosed HIV difficulties around disclosure and assumptions about HIV status to sexual partners, previous negative sexual and lifetime experiences (including early initiation of homosexual sex, having ever been raped, or forced to non-consensual sex), ever having been involved in commercial sex and experience of sexual and erectile dysfunction appear to be associated with reporting having engaged in higher risk sexual activities with casual partners and with sero-discordant regular partners, and with a recent history if STI diagnosis.

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