Partner notification highly effective at finding new HIV cases, but a third who could be tested are missed

Systematically contacting and notifying the sexual partners of people newly diagnosed with HIV is a highly efficient way of detecting previously undiagnosed cases of HIV, an audit conducted by the British HIV Association (BHIVA) and the British Association for Sexual Health and HIV (BASHH) has found.

The proportion of contacts of newly diagnosed people who also had HIV was 21%, rising to 26.5% if the newly diagnosed person was their regular partner, Dr Michael Rayment of London’s Chelsea and Westminster Hospital told the 2013 BHIVA Autumn Conference in London.

Of 1399 notified partners of diagnosed people, 293 had HIV but, Dr Rayment added, if all at-risk partners had been contacted and tested, it is estimated that this figure would rise by nearly 50%, to 431 cases.

The BASHH/BHIVA audit

The audit was a case-note review of up to 40 newly diagnosed HIV patients at each of 169 HIV services, including 156 genito-urinary medicine (GUM) clinics, totalling 2964 participants in total.

Of these newly diagnosed people, 69% were men (63% gay men), 52% were white and 33% African, and only 0.5% were classed as people who inject drugs. In the 54% whose time of infection could be estimated, 24% had acquired HIV in the last six months.

Partner notification was at least initiated in 87.5% of new diagnoses – meaning that in one-in-eight cases it was not even started. This figure varied from 62% to 97% across the different clinics.

A total of 3211 contacts of the 2470 newly diagnosed people were audited. Note that this was not the total number of people notified, as the audit looked at up to five contacts per newly diagnosed person – so many contacts of people with a lot of partners were missed out and it was estimated that a total of 6400 partners were actually contacted. This could have biased the results.

A third of the newly diagnosed people (index cases) only had one contact and, of these, 88% were audited. Only 20% of the women and 24% of the heterosexual men had more than two contacts, whereas 48% of the gay men did and 29% had five or more.

Only 9% of the regular partners of index cases were not contacted, and only 41% of ex-partners and 34% of casual contactable partners were contacted.

Of the 3211 contacts, 16% were judged not to have been at any risk of HIV (519). Altogether, twice as many people (982) were named but not informed, and it was estimated that 31% of named contacts who had been at risk of HIV did not end up being informed they had been at risk.

Of those who were at risk, 1399 people – 52% – came in for an HIV test and, of these, 293 people (21%) turned out to have HIV, or one case per 10 index cases.

This means that, out of all the newly diagnosed people, 45% of contacts came for an HIV test, and 77% of regular partners. The proportion of contacts attending to test did not vary greatly by the type of index case, but was a little higher in gay contacts (50%) and contacts under 40 (52%).

HIV prevalence in tested contacts did not greatly vary between types of people. However, it was somewhat higher in black Africans (25%) and significantly higher (27%) in the 890 people who were the primary partner of the index case.

Of the 422 non-informed people who were judged to be ‘potentially contactable’, it is estimated that 138 (33%) had HIV, of whom 62, or 45%, were the regular partner of the index case.

Partner notification is an ongoing process. The proportion of at-risk partners who attended for a test was measured in this audit at three months after notification, but 93% had attended by six months after notification and 97% by one year after notification.

“Partner notification is a highly effective strategy for diagnosing HIV,” said Michael Rayment. He added, however, that up to a third of contactable partners remained undiagnosed, and that more effort needed to be put into diagnosing ex-partners and casual partners.