Diaphragms and lubricant are not effective HIV prevention for women, major trial shows

Latex diaphragms and lubricating gel provide no additional protection against HIV infection when the diaphragm and gel are used in conjunction with male condoms and after safer sex counselling, a large randomised controlled trial has found. The Methods of Improving Reproductive Health in Africa (MIRA) study included just under 5,000 sexually active women and the results are published in the July 13^th edition of The Lancet.

Although the investigators write that the findings of their study are “disappointing”, they nevertheless found that even though women in the diaphragm arm of their study reported significantly lower levels of condom use, they did not have an increased risk of infection with HIV. They were unable to say, however, due to the small number of women using diaphragms but not condoms, if diaphragms were providing some measure of protection against HIV.

It is estimated that up to 20% of the sexually active population in Zimbabwe and South Africa are HIV-positive. Women in these countries have double the risk of infection with HIV. This is because of a combination of power imbalances and cultural issues, meaning that women are often unable to negotiate the use of male condoms. Low-cost prevention methods that can be controlled by women are therefore urgently needed. As pharmaceutical interventions are still some years away, an international team of investigators designed a large randomised trial to see if a cervical diaphragm offered any protection against infection with HIV.

The diaphragm has a long history of use throughout the world as a method of contraception. The device is fitted internally, covering the cervix and prevents semen from entering the upper genital tract. It can be used without detection by sexual partners.

Evidence from observational studies suggests that use of a diaphragm can reduce the incidence of bacterial sexually transmitted infections, such as gonorrhoea and chlamydia, infections that are known to increase the risk of exposure to HIV resulting in infection with the virus. It is thought that the diaphragm may also protect against HIV infection in other ways. By covering the cervix, diaphragms prevent cells with a particular vulnerability to HIV from being exposed to semen.

Results

A total of 309 women seroconverted for HIV during the study, providing an incidence rate of 4% per 100 person years. The incidence rates were almost identical in the intervention group (4.1%) and the condom group (3.9%). The investigators therefore concluded that diaphragms and lubricant gel offered no additional protection against infection with HIV when provided in addition to condoms and HIV risk-reduction education.

Study design

Just under 5,000 sexually active women aged between 18 – 49 years in Durban, Johannesburg and Harare were recruited to the trial. They were screened for sexually transmitted infections and HIV at baseline and then randomised into one of two groups. Individuals in the intervention group were provided with a clinician-fitted latex diaphragm and water-based lubricant. They were also given a supply of male condoms and received safer-sex counselling. Women in the control group only received condoms and counselling. The study ran between 2003 and 2006 and at quarterly intervals the women were tested for HIV and other sexually transmitted infections and asked about their level of diaphragm and/or condom use.

No higher HIV incidence in diaphragm group despite much lower condom use

However, although HIV incidence rates were identical in the two arms of the study, the women randomised to use diaphragms reported significantly lower use of condoms (54% versus 85%, p

Lead investigator, Dr Nancy Padian was asked by aidsmap.com if the results of her study suggested that diaphragms may, by protecting cells vulnerable to HIV infection in the upper genital tract and cervix, help lower the risk of HIV infection even if condoms were not used. She replied: "The bottom line is that we don’t know, but we can’t rule it out. There weren’t enough women in the study who used diaphragms but did not use condoms to make statistically valid inferences. It’s unfortunate that we don’t have more definitive data because that question has enormous public health significance."

The investigators also noted that reported condom use increased significantly in both arms of the study from baseline (p

Adherence to diaphragm use was far from universal amongst women in the intervention arm. Approximately 70% reported consistent use, and the authors of an accompanying editorial note that this level of compliance is similar to that observed in studies examining the safety and efficacy of tenofovir as pre-exposure prophylaxis.

“We observed no protective benefit from providing the diaphragm and lubricant,” conclude the investigators, “women who cannot convince their male partners to use condoms are still in urgent need of a female-controlled method of protection.”