The role of social marketing in sexually transmitted diseases/HIV protection in 4600 sexual contacts in urban Zimbabwe
In Zimbabwe, over 25% of adults are HIV positive . To curtail the epidemic, the government started promoting condom use, especially in non-marital relationships. Since 1996, Population Services International (PSI) has implemented a USAID/British Department for International Development-funded condom social marketing program that distributes subsidized Protector Plus condoms, and promotes their use through an extensive mass media advertising and promotion campaign. Protector Plus sales increased from 1.9 million in 1996, to 4.8 million in 1998, to 8.9 million in 1999. Considering that government distribution reportedly stagnated at 50 million condoms annually and commercial sales remain negligible (Chaganti and Boner, personal communication), the role of social marketing in HIV prevention appears to have increased.
We estimated the proportion of sex acts protected by social marketing condoms using data on over 4600 sexual contacts, obtained from a prospective cohort study of male workers in urban Zimbabwe.
Sexual contact-specific information is usually estimated using retrospective questions or prospective coital diaries . To avoid the problems encountered in such studies (e.g. recall problems and the non-completion of diaries), this study used a prospective cohort study with interviewer-administered daily questionnaires .
A 6 week prospective cohort survey of 222 male factory and blue-collar workers in Harare and Bulawayo, the two largest cities in Zimbabwe, was implemented by Target Research Inc. in October–November 1999. The sample consisted of purposely selected sexually active men aged 20–35 years. Informed consent was obtained verbally. To minimize dropout, respondents were paid Z$500 (US$10). A baseline questionnaire collected detailed background information. For 6 weeks, participants were visited each week day and interviewed about sexual contacts during the previous day. The observation period covered 9324 person-days, during which the respondents reported 4601 sexual contacts, of which 47.3% were with a spouse, 31.6% with a regular non-marital partner, and 21.1% with a casual partner (including commercial sex workers and other partners).
One quarter of the interviews (24.3%) were conducted in Bulawayo. A total of 79.3% of the men were in their 20s, and 45.5% were single. Most men had attended senior high school (83.3%), and had a medium–high socioeconomic status (60.4%). One in four men (27.5%) reported having had four or more casual partners in the past year; 92.3% had ever used condoms, but only 52.7% had used one in their last sex act.
Fig. 1 shows the percentage of all sexual contacts that, according to the respondents, were protected by condoms (Protector Plus, commercial, or free/public sector). Overall, 48.8% of all sexual contacts were protected: 34.6% by Protector Plus, 4.6% by commercial brands, and 9.6% by free condoms. Although national government condom distribution reportedly exceeds social marketing sales, a high use of social marketing condoms was expected for our sample, because urban workers can afford to purchase them. Nevertheless, we cannot rule out the possibility that intensive Protector Plus advertising may have caused some men to report using this brand incorrectly.
Distinguishing by partner type confirms  that sexual contacts with spouses were much less likely to be protected (11.0%) than those with regular non-marital partners (77.1%) or casual partners (90.8%). Sexual contacts for each partner type were much more likely to have been protected by social marketing condoms than commercial or free condoms. For example, the 90.8% of protected sexual contacts with casual partners consisted of 55.6% protected by the social marketing brand, compared with only 9.7% by commercial brands, and 25.