No added STD protection from spermicidal condoms
Condoms treated with the spermicide nonoxynol-9 (N-9) offer no greater protection against sexually-transmitted diseases than do regular condoms, according to recent study results.1
Family planning program administrators may want to consider these findings in choosing condom supplies for their facilities, notes Ronald Roddy, MPH, senior epidemiologist with Family Health International (FHI) in Research Triangle Park, NC, and the study's lead investigator.
"In my opinion, programs which have little funding should provide regular lubricated condoms because they are cheaper and have longer expiration times," Roddy asserts. "However, if the clientele of the program will actually use N-9 lubricated condoms more because of some physical quality, and they have data on it, they may want to spend the money for the N-9 condoms."
Individuals should use whichever condom they prefer but realize they probably won't get more protection if they buy the N-9 condoms, he says.
Researchers with FHI and Profamilia in Santo Domingo, Dominican Republic, enlisted 635 female sex workers who attended three local STD clinics for the randomized controlled trial. The study compared the cervical infection, trichomoniasis, and genital irritation rates of women assigned to the N-9 condom group with those in the plain silicone-lubricated condom group.
The investigators attempted to follow the women for 24 weeks or until gonorrheal or chlamydial cervicitis developed. Women were scheduled to return for follow-up visits every two weeks.
Of the 635 women in the study, 275 did not return to the clinic after enrollment. Loss to follow-up was 42% for the N-9 group and 45% for the plain condom group. About 17% of each group remained in the study for the full 24 weeks.
No significant difference occurred in rates of cervical infections between the women using N-9 or silicone-lubricated condoms, the researchers found. Looking separately at cervical infections and vaginal infections, N-9 condoms may have been slightly better for vaginal infections, but not by much, they say. There was no clear indication the N-9 condoms produced a greater rate of genital discomfort or problems. "This study did not find that women who used the N-9 condoms had more infections or more reported irritation," Roddy says. "That is consistent with N-9 film studies that I have done in Thailand and Cameroon."2 (For more on the Cameroon study, see STD Quarterly, a supplement to Contraceptive Technology Update, June 1997, p. 71.)
Keep in mind the loss to follow-up when evaluating the results, says Michael Rosenberg, MD, MPH, clinical professor of OB/GYN and epidemiology at the University of North Carolina and president of Health Decisions, both in Chapel Hill. "The marked loss to follow-up both reduces the number of analyzable subjects and raises the possibility of selection bias. Forty-three percent of subjects enrolled had no follow-up, and the character - istics of these and other women who did not complete the study suggest higher STD risk. Higher risk may translate to less effective condom use and a greater opportunity of demonstrating a difference between condom groups, assuming such a difference were present."
The study doesn't address the issue of how much N-9 is available to the cervix to prevent infection. "The authors point out that questions exist regarding distribution of spermicide within the vagina, particularly in regard to the cervix, the site of infection for gonorrhea and chla mydia," Rosenberg says. "The relatively small amounts may also contribute to the lack of symptoms of irritation in the spermicide-condom group."
Although spermicides are effective against common STD organisms, the amount on condoms is only about a third of that in vaginal spermicides, he notes. An earlier study found the concentration of active ingredient in spermicidal condoms was insufficient to minimize the risk of HIV transmission.3 Researchers in that trial found nearly 50% of the spermicide leached into the condom.
While condoms remain a key defense against HIV and STDs, researchers are studying new woman-controlled devices as well. Gel formulations of N-9 offer promise as the next step. FHI is researching an N-9 gel for gonorrhea and chlamydia protection, with the National Institutes of Health looking into an N-9 gel for HIV protection, Roddy says. Other products are in the pipeline in pre-clinical and Phase I testing, he reports.
References
1. Roddy RE, Cordero M, Ryan KA, et al. A randomised controlled trial comparing nonoxynol-9 lubricated condoms with silicone lubricated condoms for prophylaxis. STI 1998; 74:116-119.
2. Niruthisard S, Roddy RE, Chutivongse S. Use of nonoxynol-9 and reduction in rate of gonococcal and chlamydial cervical infections. Lancet 1992; 339:1,371-1,375.
3. Trap R, Trap B, Petersen CS. Evaluation of the amount of nonoxynol available in condoms for the inhibition of HIV using a method based on HPLC. Int J STD AIDS 1990; 1:449.
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