In order to maximise confidence in its effectiveness, a vaginal microbicide ring for women would ideally need to be flexible, translucent and not too slippery, a focus group of women has told researchers. Many also said they would ideally like a ring that could be removed for sex or for cleaning, as long as drug levels were maintained for long enough while it was removed.
The forthcoming Conference on Retroviruses and Opportunistic Infections (CROI) in Boston will feature effectiveness results from the two big studies of a vaginal ring designed to prevent HIV, the ASPIRE Study and the Ring Study.
Both studies feature a flexible plastic ring that fits comfortably high up inside the vagina and provides sustained delivery of anti-HIV drugs over a period of time in order to stop HIV infection. Vaginal rings are already used in many countries to deliver hormonal contraception. In the ASPIRE and Ring studies, the drug used is dapivirine, a non-nucleoside HIV drug (NNRTI) that was never developed as a treatment.
Previous prevention studies have learned that the make-or-break factor that determines the success of a biomedical prevention method is not so much its intrinsic efficacy as whether people actually use it – and that is governed by perceptions that may have little to do with the scientific facts of the matter. HIV studies whose failure to produce a positive result was largely due to the views of participants include the VOICE and Fem-PrEP studies of a microbicide gel and oral PrEP. In addition, as the FACTS 001 study of a microbicide gel shows, even in situations where participants trust researchers and try and adhere as best they can to the method on trial, lifestyle issues may make it difficult.
In the ring studies, therefore, it may be perceptions of the rings rather than understanding of hard facts that makes the difference to participant adherence and therefore the success of the study.
To see what a group of women thought of vaginal rings and what factors influenced their beliefs about usability and efficacy, the researchers invited a focus group of 21 women with experience of using vaginal rings for contraception to give their opinions about different ring characteristics and what they meant to them.
The researchers asked the women to inspect and comment on four prototype placebo vaginal rings. They were all women with experience of contraceptive rings but were not asked to use the rings as part of the study. The rings were not replicas of the rings used in the HIV prevention studies, either, as the researchers wanted to capture perceptions of general rather than specific ring properties. They used four different prototype rings that varied in the hardness of the plastic used, whether it has a shiny or matte exterior, opacity versus translucence, and the diameter of the ring cylinder (the plastic ‘bore’, not the diameter of the whole ring).
It’s important to note that this was a group of women very different from the African women involved in the HIV ring studies. These were US women, two-thirds were of white ethnicity, all well-educated and pretty well off (half earned more than $36,000 a year). Only four had had a baby before. In addition the regimen for a contraceptive ring is different for an HIV ring: contraceptive rings are designed to be worn for 21 days a month but taken out during a woman’s period; HIV rings are designed to be worn all the time and replaced once a month or less.
The women were asked to give their opinions on how easy the different rings would be to put in; whether they could fall out; whether the user would be aware of them all the time; whether they would affect sex; whether their use could be concealed from a partner; and how long they would feel comfortable using them.
The most important quality for the women was flexibility, which involved a combination of a ring made with a softer plastic and using a thinner bore. A more rigid ring was experienced as difficult to put in. In order to insert their rings into the correct place, women used a variety of strategies. Most squeezed the ring till it was oval and inserted it longitudinally. A minority actually twisted it into a figure-of-eight shape. The more flexible rings were able to spring back into the proper shape spontaneously inside the vagina but not in such a way that they would be uncomfortable.
One woman said of the less flexible ring: “Since it’s harder to squeeze, it makes me feel like it’s kind of stiffer and less flexible so when it goes in, are you gonna feel it?”
Another added: “I think it would be hard to find a comfortable position for it…just because it’s so stiff and it wants to hold that round shape.”
Women referred to a ‘fingernail test’, meaning that they preferred a ring whose plastic was soft enough to be marked with a fingernail easily and did not spring back immediately.
Another important consideration was the surface appearance of the ring. Matte rings were preferred to shiny rings for two reasons, Firstly, women felt the shiny rings would be more difficult to insert without dropping and more likely to fall out or be expelled.
Secondly, although this was not a prompted question, many women thought the matte ring looked more like something that could actually deliver the drug: “It’s almost, like, a little more porous. Like when I touch it, I can picture the hormones, you know, coming out of it in contact with my body.”
Another preference was that the ring should be translucent rather than opaque. Translucence was associated in women’s minds with clarity of function: they somehow felt more confident that it would be dispensing the drug: “I’m definitely for a see-through…I can see the liquid, hormones, I like that. This looks like it’s gonna do what it’s gonna do.”
Flexibility or ‘spring’ also meant to the women that the ring would have a natural tendency to place itself in the right position. Women were very uncertain how important exact placing of the ring was. Some had been told that as long as it was securely in the vagina, exact placement was not crucial, while others had been told it had to fit exactly over the cervix like a diaphragm. Either instruction was a cause for anxiety; women told that exact placement was unimportant were less convinced of the ring’s consistent efficacy, while ones told it was important were worried they would place it incorrectly or that its position would shift during sex or other movement.
Another reason for preferring smaller-bore rings was because it was less likely to be noticed by the partner during sex. For these women, covert use was not important, but causing discomfort to their partner was. “My husband would complain about it…bothering with the super-sensitive underside, like there the head meets the shaft of the penis; it might get caught on the bottom of the ring.”
When asked to consider specifically the idea of a ring for HIV or STI prevention that had to be used all the time, and possibly for longer, women changed their minds slightly. They thought the wider-diameter and less flexible ring might be more durable and more effective for longer durations, and be able to contain more drug.
Many women discussed hygiene issues related to ring use. Some said they would feel the need to clean it regularly, noting that they regularly remove their contraceptive ring and rinse it off while showering. Some even removed it during sex, reasoning that as long as they replaced it immediately, adequate drug levels in their vagina would be be maintained.
Hygiene for ring users is clearly important and an issue that may affect adherence – depending on site, between 4 and 18% of participants in the Ring study reported removing their ring during their period or for cleaning. In a previous acceptability study in the US, 41% of women said they would prefer a ring that could be used episodically and 17% said they didn’t want to use one during their period.
This study reinforces findings that, in general, women are reasonably assured about the efficacy of vaginal rings and usually find that fears about ongoing discomfort are misplaced – but that researchers may underestimate women’s concerns that wearing a ring all the time could be unhygienic and some women’s feelings that the ring might impair sexual pleasure and acceptability to partners.
Morrow Guthrie K et al. The promise of intravaginal rings for prevention: user perceptions of biomechanical properties and implications for prevention product development. PLoS ONE 10(12): e0145642. doi: 10.1371/journal.pone.0145642. 2015.