Though condoms and spermicides are widely recommended for “safer sex” practices, the products’ efficacy is more supposed than proven.
Investigators are less than certain that these agents can protect against the human immunodeficiency virus. They hedged in their responses to clinicians’ questions here at the Fourth International Conference on AIDS.
“Are they any blood or not? Are we making a mistake recommending them?” asked Dr. Donald Francis, a CDC AIDS adviser to the California state department of health, seeking a bottom-line assessment of condoms.
“I hate to be cagey, but we don’t really know,” replied Dr. Robert Nakamura, a professor of obstetrics and gynecology at Women’s Hospital, Los Angeles County-University of Southern California Medical Center, who’d reported results from in vitro testing of about 30 types of commercially available latex condoms.
All types were flawed. Smooth or textured, round-tipped or reservoir, straight-sided or tapered, with or without lubrication, with or without spermicide–none of the condoms tested were without flaws.
Products were rated on a scale based on the results of a variety of tests, including water leakage, tensile strength, air burst strength, and pinhole electrical conductivity. Though water leakage seemed most reflective of overall integrity, no single test was conclusive, and the relationship of any defect to a condom’s in vitro ability to block HIV transmission hasn’t been established, Dr. Nakamura noted. He declined to rate the various products.
Dr. David Cohn, director of disease control at the Denver Disease Control Service, reported a high rate of condom breakage among gay men participating in a CDC-sponsored longitudinal study of risk reduction. About 30% of men reporting condom use in anal sex had experienced at least one instance of breakage in the previous six months. Most noticed the breakage within the first five minutes, but one-third only after withdrawal.
Researchers found no correlation between condom breakage and penis size or ability to maintain an erection.
Dr. Nakamura said petroleum-based lubricants tend to weaken a condom, but water-soluble lubricants do not.
Dr. Cohn said his team encourages the use of nonoxynol-9 either inside or outside the condom as backup protection in case of breakage. The virucidal agent is the active ingredient in most commercially available spermicides. Findings that confirm the ability of nonoxynol-9 to inactivate HIV in vitro were reported by Dr. Lionel Resnick, chief of the retrovirology labs at Mount Sinai Medical Center in Miami Beach. He noted that the spermicide melts away the fragile viral envelope and that the concentration needed to inactivate cell-associated virus is higher than that for cell-free virus.
But when asked how the in vitro spermicide concentration compares with that “in common use,” Dr. Resnick said he hadn’t the “slightest idea.” Scientists “don’t know how much nonoxynol-9 gets absorbed, how quickly, [or] how pH variations or any number of other factors may alter in vitro effects.”
Another investigator who conducted similar nonoxynol-9 studies, however, was more sanguine about the possibility of extrapolating in vitro findings to clinical reality. Dr. Miroslav Malkovsky, senior scientist at the Medical Research Council clinical research center in Middlesex, England, reported on the ability of four spermicidal preparations–one condom lubricant and three vaginal jellies–to obliterate all evidence of HIV RNA activity on the Southern blot test. Viral concentrations were high, and the various preparations all worked in less than 30 seconds, he said.
But a team, whose scheduled poster presentation on the effect of nonoxynol-9 use on HIV transmission in Nairobi prostitutes was withdrawn, found no spermicide-related change in HIV serostatus, regardless of condom use.