Pre-emptive strike against STI-go-round

Antibiotics for sexual partners quells reinfection

By Owen Dyer

With STI rates threatening to explode in North America, and with no new treatments available to break the cycle of reinfection, the group decided to see what a new model of partner intervention could achieve. Their research is published in the February 17 issue of the New England Journal of Medicine (NEJM).

BUDDY SYSTEM
"The current standard approach to gonorrhea and chlamydial infection is to request that patients themselves notify their sexual partners, who are then expected to seek medical evaluation and treatment," write Baltimore specialists Emily Erbelding and Jonathan Zenilman in an accompanying NEJM editorial. "This has largely been a failure."

In light of this dismal record, the researchers set out to evaluate a novel technique for reaching the partners of patients diagnosed with these conditions. The plan was simple. Instead of demanding that sexual partners come in for an embarrassing interview, the researchers gave 'partner packets' of antibiotics to patients, or left them for pickup at the clinic reception.

The trial involved 1,860 heterosexual patients, who were randomized to either receive the partner packets or to standard partner referral requiring a medical evaluation. The primary measure of success was the reinfection rate among the original patients, and the partners themselves were never evaluated.

Persistent or recurrent infection was found in 121 of 931 patients assigned to standard partner referral (13%), and in 92 of 929 patients randomized to the 'expedited partner treatment' group (10%). In other words, patients given antibiotics for their partners with no questions asked were only 76% as likely to suffer recurrent infection as those processed in the normal way.

But almost all of the clinical benefit was seen in patients with gonorrhea, while chlamydia patients saw minimal gains. Among gonorrhea patients, expedited partner treatment led to recurrent or persistent infection rates of just 3%, compared to 11% in the standard referral group. The benefit for chlamydia patients was less spectacular — just 11% versus 13%.

ETHICAL HURDLES
In Canada, reported chlamydia rates are only about half those seen in the US, but there is little cause for complacency. After years of decline, rates started rising in the late 90s and are now on a clear upward path.

Dr Gerald Evans, director of internal medicine at Queen's University and chief of the division of infectious diseases at Kingston General Hospital, thinks the researchers' revolutionary approach to partner treatment could bring real clinical benefits. But he predicts the method will face numerous bureaucratic and ethical hurdles. "Here in Ontario, giving antibiotics to people without a medical assessment would generally be considered suboptimal treatment, and falls below the standards of many guidelines," he says.

Canada and the US have a similar approach to STIs. In the case of the most serious diseases, like syphilis and HIV, staff will often make the effort to locate partners themselves. This is particularly true of highly-organized STI clinics. But the strain on resources is immense, and in some areas such efforts are impossible.

It's precisely those areas with the fewest services for partners that have the highest rates of STIs, say the NEJM editorialists. In the US, no progress has been made towards goals set in 2000 by the Health Department for reducing infection rates.

Dr Evans says this selfsame manpower issue could hamper the efforts of the 'partner packet' system, were it to be initiated in clinics. "Tracking down partners is difficult and time-consuming, but the benefits of reaching more people must be set against the risks of preventable adverse drug reactions," he says. "Having said that, these antibiotics are generally pretty well tolerated, and I notice there were no adverse reactions in this particular trial. And of course, even an examination can't guarantee that the potential for adverse reactions will be spotted."

IMPERFECT SOLUTION
Dr Evans does have a couple of concerns about the approach. "Another issue is that we would miss the opportunity to screen partners for more serious conditions like HIV," he says. "A final concern is that if people didn't comply with treatment properly, we would be increasing antibiotic resistance for little gain. But in this case they used a single-dose formulation, which at least eliminates the problem of patients only taking half their course of antibiotics."

"I think this approach deserves further investigation, but ideally you'd want to measure the effect on the partners, as well as the patients who actually come in. Whatever happens, I think there would be some persuading to do before this approach became common in Canada."